KR100960078B1 - Optical Isolator Using Surface Plasmon Resonance - Google Patents

Abstract

An optical isolator using surface plasmon resonance is disclosed. The total reflection element totally reflects the incident light input to the front surface. The metal thin film has a front surface disposed in contact with a rear surface of the total reflection element, and forms a surface plasmon resonance wave at the rear surface by incident light input at a surface plasmon resonance angle on the front surface of the total reflection element. The first incident waveguide is disposed to form a normal line perpendicular to the front surface of the total reflection element and a plasmon resonance angle, and the incident light input to one end is incident on the front surface of the total reflection element. The emission waveguide is disposed to be symmetrical with the first incident waveguide with respect to a normal line perpendicular to the front surface of the total reflection element, and the incident light reflected from the total reflection element is output. The second incident waveguide enters the first disturbing light into the rear surface of the metal thin film to change the surface plasmon resonance condition formed by the incident light input at the surface plasmon resonance angle so that the incident light is output to the emission waveguide. According to the present invention, the third incident waveguide receives the second disturbing light toward the rear surface of the metal thin film to satisfy the surface plasmon resonance condition for the reflected light traveling in the opposite direction to the incident light incident on the front surface of the total reflection element. By using light, the reflected light flowing in the reverse direction in the optical path can be suppressed, and the optical integrated circuit can be realized using only the optical device.

Optical isolator, surface plasmon resonance, metal thin film, total reflection element

Description

Optical isolator using surface plasmon resonance

The present invention relates to an optical isolator, and more particularly, to an optical isolator of the optical device concept using surface plasmon resonance.

Recently, due to the rapid increase in information volume due to the rapid development of information and communication, the demand for technology of ultra-high speed information and communication is increasing exponentially. One of the technologies currently being studied to accommodate this demand is optical integration. The optical integration that is currently being studied is quite advanced and has reached the point where most optical devices can be integrated on the same substrate. However, an optical isolator is still an optical element that has difficulty in integrating unit devices on the same substrate.

An optical isolator is an optical element that blocks unwanted light that bounces back and causes noise. That is, the optical isolator is a device that allows the light to pass only in the forward direction and blocks the light in the reverse direction. By using this, it is possible to obtain high quality transmission efficiency by eliminating inherent interference that may occur during the transmission of light. 1 shows a conventional optical isolator composed of a polarizer, an analyzer, a permanent magnet, a paradata rotor, and the like. However, the existing optical isolator is composed of a magnetic material, a paradata rotor, etc., and thus there is a problem that it is difficult to integrate the optical isolator on a substrate made of a material such as InP.

The technical problem to be solved by the present invention is to provide an optical isolator that can be integrated in a substrate made of a material such as InP.

In order to solve the above technical problem, a preferred embodiment of the optical isolator according to the present invention, the total reflection element for total reflection of the incident light input to the front; A metal film having a front surface disposed in contact with a rear surface of the total reflection element, and forming a surface plasmon resonance wave at the rear surface by incident light input at a surface plasmon resonance angle on the front surface of the total reflection element; A first incident waveguide disposed to form a normal line perpendicular to the front surface of the total reflection element and the plasmon resonance angle, and configured to allow the incident light input to one end to enter the front surface of the total reflection element; An emission waveguide disposed symmetrically with the first incident waveguide with respect to a normal line perpendicular to the front surface of the total reflection element, and outputting the incident light reflected from the total reflection element; A second incident waveguide for injecting a first disturbing light into a rear surface of the metal thin film to change the surface plasmon resonance condition formed by the incident light input at the surface plasmon resonance angle so that the incident light is output to the emission waveguide; And a third incident waveguide for removing the reflected light by satisfying a surface plasmon resonance condition for the reflected light traveling in a direction opposite to the incident light incident on the front surface of the total reflection element by injecting a second disturbing light into the rear surface of the metal thin film. Equipped.

Another preferred embodiment of the optical isolator according to the present invention for solving the above technical problem, the total reflection element for total reflection of the incident light input to the front; A metal thin film disposed to be spaced apart from the rear surface of the total reflection element by a incident light input at a surface plasmon resonance angle on the front surface of the total reflection element to form a surface plasmon resonance wave on a front surface opposite to the rear surface of the total reflection element; A first incident waveguide disposed to form a normal line perpendicular to the front surface of the total reflection element and the plasmon resonance angle, and configured to allow the incident light input to one end to enter the front surface of the total reflection element; An emission waveguide disposed symmetrically with the first incident waveguide with respect to a normal line perpendicular to the front surface of the total reflection element, and outputting the incident light reflected from the total reflection element; A second incident waveguide for injecting a first disturbing light into a rear surface of the metal thin film to change the surface plasmon resonance condition formed by the incident light input at the surface plasmon resonance angle so that the incident light is output to the emission waveguide; And a third incident waveguide for removing the reflected light by satisfying a surface plasmon resonance condition for the reflected light traveling in a direction opposite to the incident light incident on the front surface of the total reflection element by injecting a second disturbing light into the rear surface of the metal thin film. Equipped.

In order to solve the above technical problem, another preferred embodiment of the optical isolator according to the present invention, the total reflection element for total reflection of the incident light input to the front; A metal film having a front surface disposed in contact with a rear surface of the total reflection element, and forming a surface plasmon resonance wave at the rear surface by incident light input at a surface plasmon resonance angle on the front surface of the total reflection element; A first incident waveguide disposed to deviate by a predetermined angle from a normal line perpendicular to the front surface of the total reflection element and the plasmon resonance angle, and to enter the incident light input to one surface of the total reflection element; An emission waveguide disposed symmetrically with the first incident waveguide with respect to a normal line perpendicular to the front surface of the total reflection element, and outputting the incident light reflected from the total reflection element; And a second incident waveguide for removing the reflected light by satisfying a surface plasmon resonance condition for the reflected light incident to the rear surface of the metal thin film and traveling in a direction opposite to the incident light incident on the front surface of the total reflection element. .

In order to solve the above technical problem, another preferred embodiment of the optical isolator according to the present invention, the total reflection element for total reflection of the incident light input to the front; A metal thin film disposed to be spaced apart from the rear surface of the total reflection element by a incident light input at a surface plasmon resonance angle on the front surface of the total reflection element to form a surface plasmon resonance wave on a front surface opposite to the rear surface of the total reflection element; A first incident waveguide disposed to deviate from the normal line perpendicular to the front surface of the total reflection element and a predetermined angle with respect to the plasmon resonance angle, and to allow the incident light inputted at one end to the front surface of the total reflection element; An emission waveguide disposed symmetrically with the first incident waveguide with respect to a normal line perpendicular to the front surface of the total reflection element, and outputting the incident light reflected from the total reflection element; And a second incident waveguide for removing the reflected light by satisfying a surface plasmon resonance condition for the reflected light incident to the rear surface of the metal thin film and traveling in a direction opposite to the incident light incident on the front surface of the total reflection element. .

Another preferred embodiment of the optical isolator according to the present invention for solving the above technical problem, the total reflection element for total reflection of the incident light input to the first surface; A metal thin film having a front surface disposed in contact with the first surface of the total reflection element, and forming a surface plasmon resonance wave at the rear side by incident light input at a surface plasmon resonance angle on the front surface of the total reflection element; A normal line perpendicular to the first surface of the total reflection element by entering the incident light input to the second surface of the total reflection element, the incident light incident on the second surface of the total reflection element proceeds inside the total reflection element A first light input unit arranged to be incident on a second surface of the total reflection element while forming the plasmon resonance angle; The incident light is disposed to be symmetrical with the first light input unit with respect to a normal line perpendicular to the first surface of the total reflection element, and is reflected by the first surface of the total reflection element and exits the incident light emitted through the third surface of the total reflection element. An optical output unit for receiving the output through the other end; A second light input unit configured to change a surface plasmon resonance condition formed by incident light input to the surface plasmon resonance angle by injecting a first disturbing light into a rear surface of the metal thin film so that the incident light is output to the light output unit; And a third light input unit configured to remove the reflected light by satisfying a surface plasmon resonance condition for the reflected light traveling in a direction opposite to the incident light incident on the front surface of the total reflection element by injecting a second disturbing light into the rear surface of the metal thin film. Equipped.

Another preferred embodiment of the optical isolator according to the present invention for solving the above technical problem, the total reflection element for total reflection of the incident light input to the first surface; A surface plasmon resonance wave is disposed on the first surface of the total reflection element and spaced apart from the first surface by a incident light input at a surface plasmon resonance angle on the front surface of the total reflection element. Metal thin film to form; A normal line perpendicular to the first surface of the total reflection element by entering the incident light input to the second surface of the total reflection element, the incident light incident on the second surface of the total reflection element proceeds inside the total reflection element A first light input unit arranged to be incident on a second surface of the total reflection element while forming the plasmon resonance angle; The incident light is disposed to be symmetrical with the first light input unit with respect to a normal line perpendicular to the first surface of the total reflection element, and is reflected by the first surface of the total reflection element and exits the incident light emitted through the third surface of the total reflection element. An optical output unit for receiving the output through the other end; A second light input unit configured to change a surface plasmon resonance condition formed by incident light input to the surface plasmon resonance angle by injecting a first disturbing light into a rear surface of the metal thin film so that the incident light is output to the light output unit; And a third light input unit configured to remove the reflected light by satisfying a surface plasmon resonance condition for the reflected light traveling in a direction opposite to the incident light incident on the front surface of the total reflection element by injecting a second disturbing light into the rear surface of the metal thin film. Equipped.

Another preferred embodiment of the optical isolator according to the present invention for solving the above technical problem, the total reflection element for total reflection of the incident light input to the first surface; A metal thin film having a front surface disposed in contact with the first surface of the total reflection element, and forming a surface plasmon resonance wave at the rear surface by incident light input at a surface plasmon resonance angle on the front surface of the total reflection element; A first light input unit arranged to deviate from a normal angle perpendicular to the front surface of the total reflection element and a predetermined angle with respect to the plasmon resonance angle, and incident the incident light input to one surface to the front surface of the total reflection element; An optical output unit disposed to be symmetrical with the first light input unit with respect to a normal line perpendicular to the front surface of the total reflection element, and outputting the incident light reflected from the total reflection element; And a second light input unit configured to remove the reflected light by satisfying a surface plasmon resonance condition for the reflected light incident to the back surface of the metal thin film and traveling in a direction opposite to the incident light incident on the front surface of the total reflection element. .

Another preferred embodiment of the optical isolator according to the present invention for solving the above technical problem, the total reflection element for total reflection of the incident light input to the first surface; A surface plasmon resonance wave is disposed on the first surface of the total reflection element and spaced apart from the first surface by a incident light input at a surface plasmon resonance angle on the front surface of the total reflection element. Metal thin film to form; A first light input unit arranged to deviate from a normal angle perpendicular to the front surface of the total reflection element and a predetermined angle with respect to the plasmon resonance angle, and incident the incident light input to one surface to the front surface of the total reflection element; An optical output unit arranged to be symmetrical with the first light input unit with respect to a normal line perpendicular to the front surface of the total reflection element, and outputting the incident light reflected from the total reflection element; And a second light input unit configured to remove the reflected light by satisfying a surface plasmon resonance condition for the reflected light incident to the back surface of the metal thin film and traveling in a direction opposite to the incident light incident on the front surface of the total reflection element. .

According to the optical isolator using the surface plasmon resonance according to the present invention, it is possible to suppress the reflected light flowing in the reverse direction in the optical path by using light, to implement an optical integrated circuit using only optical elements, pure optical computer through optical integration The production of may be possible.

Hereinafter, exemplary embodiments of an optical isolator according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a diagram showing the configuration of the first embodiment of the optical isolator according to the present invention.

Referring to FIG. 2, the first embodiment 200 of the optical isolator according to the present invention is implemented with a Kretschmann structure, and includes a prism 210, a metal thin film 220, a first light input unit 230, and a light. An output unit 240, a second light input unit 250, and a third light input unit 260 are provided.

The first surface of the metal thin film 220 is in contact with the bottom surface of the prism 210, and the first light input unit 230 and the light output unit 240 are in contact with the remaining two surfaces of the prism 210 or spaced a predetermined distance apart. Are arranged. When monochromatic light, such as a laser, is incident on the prism 210 having a high refractive index through the first light input unit 230, the incident light is totally reflected at the bottom of the prism 210, and thus the light output is located opposite to the first light input unit 230. Reach to section 240. However, when the incident angle of incident light becomes a specific surface plasmon resonance angle based on a normal perpendicular to the bottom surface of the prism 210 (ie, the surface in contact with the metal thin film 220) with respect to the metal thin film 220 of a given thickness, the surface Plasmon resonance occurs and the light directed to the light output unit 240 is rapidly reduced. The surface plasmon resonance coincides with the incident light in a direction parallel to the interface between the prism 210 and the metal thin film 220 and the surface plasmon resonance wave (first SPR wave) traveling along the second surface of the metal thin film 220. (I.e., optical conditions occur when the moment of the TM mode light wave (Transverse Magnetic light wave) becomes equal to the moment of the Surface Plasmon Wave propagating in the metal thin film 220). Therefore, the first light input unit 230 should be disposed such that incident light is input to the prism 210 at a surface plasmon resonance angle with respect to a normal line perpendicular to the bottom surface of the prism 210. In addition, the light output unit 240 should also be disposed such that the incident light totally reflected from the bottom of the prism 210 faces the light output unit 240 at a surface plasmon resonance angle with respect to a normal perpendicular to the bottom of the prism 210. do. Under such optical conditions, the photon energy incident to the prism 210 is substantially all the surface plasmon resonance wave flowing through the second surface of the metal thin film 220 (that is, the metal thin film 220 and the dielectric (air in this embodiment)). Vibration of charge density occurring at the interface between them). This surface plasmon resonance occurs only when the TM polarized wave, a component perpendicular to the interface, is incident. When surface plasmon resonance occurs as described above, the energy of light directed toward the light output unit 240 becomes almost zero.

The second light input unit 250 is disposed in contact with the second surface of the metal thin film 220 or spaced a predetermined distance apart. In this case, a thin film made of a dielectric material having a refractive index lower than the refractive index of the prism 210 may be in contact with the second surface of the metal thin film 220. In this state, when the first disturbing light such as a laser enters the second surface of the metal thin film 220 through the second light input unit 250, the electrons generated by the plasmon resonance on the second surface of the metal thin film 220 are formed. It affects the collective vibration and changes the surface plasmon resonance conditions. As a result, the condition in which the light energy after reflection is rapidly decreased at a specific angle as a result of surface plasmon resonance is changed to increase the light energy reaching the light output unit 240. As such, when the first disturbing light is applied to the second surface of the metal foil film 220, the incident light is totally reflected at the bottom surface of the prism 210 and directed toward the light output unit 240. In this case, the second light input unit 250 may include a first light input unit with respect to a plane that bisects an angle between the first light input unit 230 and the light output unit 240 so that the incident direction of the first disturbing light coincides with the incident direction of the incident light. It is preferably arranged at an angle toward 230. In addition, the incident angle of the first disturbed light inputted through the second light input unit 250, the wavelength of the disturbed light, and the intensity of the disturbed light are based on the normal perpendicular to the second surface of the metal thin film 220. The surface plasmon resonance angle corresponding to the incident light and the intensity of the incident light are determined experimentally.

At this time, the reflected light from the light output unit 240 to the first light input unit 230 is present, and such reflected light causes problems such as crosstalk of signals and generation of noise. In order to solve this problem, the present invention eliminates the reflected light directed toward the first light input unit 230 by satisfying the surface plasmon resonance condition for the reflected light. Accordingly, as described above, in the state where the light is output from the light output unit 240 by the first disturbing light, the third light input unit 260 disposed in contact with the second surface of the metal thin film 220 or spaced a predetermined distance apart. The second disturbing light, such as a laser, is incident on the second surface of the metal thin film 220 through. In this case, the third light input unit 260 may be configured such that the light output unit (260) is divided into a plane that bisects the angle between the first light input unit 230 and the light output unit 240 so that the incident direction of the second disturbing light coincides with the incident direction of the reflected light. Preferably at an angle toward 240). In addition, the incident angle of the second disturbing light, the wavelength of the second disturbing light, and the intensity of the second disturbing light are input through the third light input unit 260 based on a normal perpendicular to the second surface of the metal thin film 220. Is determined experimentally based on the refractive index of the surface, the surface plasmon resonance angle corresponding to the reflected light, and the intensity of the reflected light. As such, when the surface plasmon resonance condition for the reflected light is satisfied by the second disturbing light, a surface plasmon resonance wave (second SPR wave) traveling along the second surface of the metal thin film 220 in the opposite direction to the first SPR wave is generated. Therefore, the reflected light incident on the bottom surface of the prism 210 is removed.

FIG. 3 is a graph illustrating calculation of light waves by finite difference time domain (FDTD) method when surface plasmon resonance is induced in a surface plasmon resonator having a Kretschmann structure. Referring to FIG. 3, when a monochromatic light 310 such as a laser input to the first light input unit 230 is incident toward a medium having a high refractive index, such as a prism 210, the incident light 310 is formed on the bottom surface of the prism 210. When the incident angle of the incident light 310 based on the normal of the bottom surface of the prism 210 becomes a specific angle, the surface plasmon resonance wave 320 is induced and the light is above the critical angle. Nevertheless, the light energy 330 reflected from the bottom surface of the prism 210 toward the light output unit 240 is rapidly reduced.

4A is a graph showing the progress of light waves after incident the first disturbing light onto the second surface of the metal thin film 220 when the surface plasmon resonance is induced in the first embodiment 200 of the optical isolator according to the present invention. to be. Referring to FIG. 4A, after the surface plasmon resonance wave is formed on the metal thin film 220 by the incident light 410, the first disturbing light 420 input to the second light input unit 250 is the bottom surface of the prism 210. When incident on the second surface of the metal thin film 220 positioned at, it affects the collective vibration of electrons, thereby changing the surface plasmon resonance condition. Therefore, the light energy 430 toward the light output unit 240 reduced by the surface plasmon resonance is increased.

4B illustrates a third light input unit in a state where surface plasmon resonance conditions are changed by the first disturbing light in the first embodiment 200 of the optical isolator according to the present invention, and the light energy toward the light output unit 240 is increased. It is a graph showing the progress of light waves after the second disturbing light is incident from 260. Referring to FIG. 4B, when the surface plasmon resonance condition for the reflected light is satisfied by the second disturbing light, the reflected light is all changed to the second SPR wave and the reflected light traveling in the opposite direction to the incident light is removed. In this case, the second disturbing light does not affect the surface plasmon resonance condition for the incident light.

Fig. 5 shows the construction of a second embodiment of an optical isolator according to the present invention.

Referring to FIG. 5, the second embodiment 500 of the optical isolator according to the present invention is implemented in an auto structure, and includes a prism 510, a metal thin film 520, a support 530, and a first light input unit. 540, an light output unit 550, a second light input unit 560, and a third light input unit 570.

The first surface of the metal thin film 520 is spaced apart by a predetermined distance in parallel with the bottom surface of the prism 510, the support 530 is disposed on the second surface of the metal thin film 520, the metal thin film 520 Fix it. The support part 530 is preferably made of a transparent material (eg, thin glass) so that the first disturbed light input to the second light input part 560 may be incident on the metal thin film 520. If the thickness of the metal thin film 520 is sufficiently thick or the material of the metal thin film 520 is hard, it is not necessary to employ the support part 530. Meanwhile, a dielectric material having a lower refractive index than the prism 510 may be inserted into the space between the metal thin film 520 and the prism 510. At this time, the dielectric material to be inserted is manufactured in the form of a thin plate, one surface is in contact with the bottom surface of the prism 510 and the other surface is in contact with the first surface of the metal thin film 520. The first light input unit 540 and the light output unit 550 are disposed in contact with the other two surfaces of the prism 510 or spaced apart from each other by a predetermined distance. The second light input unit 560 is disposed in contact with the metal thin film 520 (the support unit 530 when the support unit 530 is disposed) or spaced a predetermined distance apart. In this case, the second light input unit 560 includes a first light input unit with respect to a plane that bisects an angle between the first light input unit 540 and the light output unit 550 such that the incident direction of the first disturbing light coincides with the incident direction of the incident light. It is preferably arranged at an angle toward 540.

As described with reference to FIG. 2, the first light input unit 540 of the second embodiment 500 of the optical isolator according to the present invention has a surface plasmon with respect to a normal line in which incident light is perpendicular to the bottom surface of the prism 510. It should be arranged to be input to the prism 510 to form a resonance angle. In addition, the light output unit 550 should also be disposed such that the incident light reflected from the bottom surface of the prism 510 forms the surface plasmon resonance angle with respect to a normal perpendicular to the bottom surface of the prism 510 and faces the light output unit 550. do. When the incident light input through the first light input unit 540 enters the prism 510 having a high refractive index in such an arrangement state, all photon energy is spaced apart from the bottom surface of the prism 510 by surface plasmon resonance. The light output through the light output unit 550 is rapidly reduced by changing to a surface plasmon resonance wave (first SPR wave) flowing through the first surface of the thin metal film 520.

In this state, when the first disturbed light such as a laser enters the second surface of the metal thin film 520 through the second light input unit 560, electrons generated by surface plasmon resonance on the second surface of the metal thin film 520. This affects the group vibration of the surface, changing the surface plasmon resonance conditions. Accordingly, the condition in which the light energy after the initial reflection is rapidly reduced at a specific angle is changed as a result of surface plasmon resonance, thereby increasing the light energy reaching the light output unit 550. When the first disturbing light is applied to the second surface of the metal thin film 520 as described above, the incident light is totally reflected at the bottom surface of the prism 510 to be directed to the light output part 550. In this case, the incident angle of the first disturbed light, the wavelength of the disturbed light, and the intensity of the disturbed light, which are input through the second light input unit 560 based on a normal perpendicular to the second surface of the metal thin film 520, may be determined by the refractive index of the metal thin film 520. The surface plasmon resonance angle corresponding to the incident light and the intensity of the incident light are determined experimentally.

At this time, the reflected light from the light output unit 550 to the first light input unit 540 is present, and the reflected light causes problems such as crosstalk of signals and generation of noise. In order to solve this problem, the present invention eliminates the reflected light directed to the first light input unit 540 by satisfying the surface plasmon resonance condition for the reflected light. Accordingly, as described above, in the state where the light is output from the light output unit 550 by the first disturbing light, the third light input unit 570 is disposed in contact with the second surface of the metal thin film 520 or spaced a predetermined distance apart. The second disturbance light, such as a laser, is incident on the second surface of the metal thin film 520 through. In this case, the third light input unit 570 may include a light output unit (2) for a plane that bisects an angle between the first light input unit 540 and the light output unit 550 such that the incident direction of the second disturbing light coincides with the incident direction of the reflected light. 550 is preferably disposed at an angle toward the (550). In addition, the incident angle of the second disturbing light, the wavelength of the second disturbing light, and the intensity of the second disturbing light, which are input through the third light input unit 570 based on a normal perpendicular to the second surface of the metal thin film 520, are measured by the metal thin film 520. ) Is experimentally determined based on the refractive index of), the surface plasmon resonance angle corresponding to the reflected light, and the intensity of the reflected light. As such, when the surface plasmon resonance condition for the reflected light is satisfied by the second disturbing light, the surface plasmon resonance wave traveling in the opposite direction to the first SPR wave along the second surface of the prism 510 and the metal thin film 520 (second SPR). Wave) is generated, and the reflected light incident on the bottom surface of the prism 510 is removed.

Fig. 6 is a diagram showing the configuration of the third embodiment of the optical isolator according to the present invention. The third embodiment of the optical isolator according to the present invention shown in FIG. 6 is modified to integrate the optical isolator of the Crechmann structure shown in FIG. 1 into an on-chip by a semiconductor manufacturing process.

Referring to FIG. 6, a third embodiment 600 of an optical isolator according to the present invention includes a first incident waveguide 610, a total reflection element 620, a metal thin film 630, an emission waveguide 640, and a second waveguide 640. The incident waveguide 650 and the third incident waveguide 660 are formed. Each waveguide consists of an optical signal transmission material such as an optical fiber or an optical waveguide.

One end of the first incident waveguide 610 receives incident light through a light source or an optical path. The total reflection element 620 is a device that totally reflects the incident light, and typically has a total reflection mirror. At this time, the angle formed by the normal perpendicular to the surface of the first incident waveguide 610 and the total reflection element 620 should be the surface plasmon resonance angle so as to cause surface plasmon resonance. The metal thin film 630 is formed on the rear surface of the total reflection element 620. The metal thin film 630 is formed by a general thin film deposition process. When incident light having a specific wavelength is input to the entire surface of the total reflection element 620 through the first incident waveguide 610, the metal thin film is the same as the first embodiment 200 of the optical isolator according to the present invention shown in FIG. Free electrons present on the rear surface (ie, the surface not facing the total reflection element 620) form the surface plasmon resonance wave. Therefore, the incident light reflected by the total reflection element 620 and outputted to the emission waveguide 640 exhibits a rapidly decreasing characteristic under surface plasmon resonance conditions. In this case, the emission waveguide 640 is disposed to form an angle equal to an incident angle of incident light based on a normal line perpendicular to the front surface of the total reflection element 620.

In this state, when the first disturbing light input through the second incident waveguide 650 is applied to the rear surface of the metal thin film 630, the surface plasmon resonance condition is changed by affecting the collective vibration of electrons. Accordingly, a condition in which the light energy after the initial reflection is rapidly reduced at a specific angle is changed as a result of surface plasmon resonance, thereby increasing the light energy reaching the emission waveguide 640. On the other hand, the second incident waveguide 650 has a first incident waveguide (with respect to a plane dividing the angle between the first incident waveguide 610 and the outgoing waveguide 640 so that the incident direction of the first disturbing light coincides with the incident direction of the incident light). It is preferably arranged at an angle toward 610. In addition, the incident angle of the first disturbed light, the wavelength of the first disturbed light, and the intensity of the first disturbed light input through the second incident waveguide 650 with respect to the normal line perpendicular to the back surface of the metal thin film 630 are the refractive indices of the metal thin film 630. The surface plasmon resonance angle corresponding to the incident light and the intensity of the incident light are determined experimentally.

At this time, the reflected light from the exiting waveguide 640 toward the first incident waveguide 610 is present, and the second disturbing light is incident on the rear surface of the metal thin film 630 through the third incident waveguide 660 to the surface of the reflected light. By satisfying the plasmon resonance condition, the reflected light directed to the first incident waveguide 610 may be removed. Therefore, as described above, in the state in which light is output from the emission waveguide 640 by the first disturbing light, the third incident waveguide 660 is disposed in contact with the rear surface of the metal thin film 630 or spaced a predetermined distance apart. The second disturbing light such as a laser is incident on the rear surface of the metal thin film 630. In this case, the third incident waveguide 660 is an emission waveguide 640 with respect to a plane that bisects an angle between the first incident waveguide 610 and the emission waveguide 640 so that the incident direction of the second disturbing light coincides with the incident direction of the reflected light. It is preferably arranged at an angle toward. In addition, the incident angle of the second disturbing light, the wavelength of the second disturbing light, and the intensity of the second disturbing light, which are input through the third light input unit 660 with respect to a normal line perpendicular to the back surface of the metal thin film 630, are determined by the refractive index of the metal thin film 630. The surface plasmon resonance angle corresponding to the reflected light and the intensity of the reflected light are determined experimentally. As such, when the surface plasmon resonance condition for the reflected light is satisfied by the second disturbing light, a surface plasmon resonance wave (second SPR wave) is generated along the entire surface of the metal thin film 630 in the opposite direction to the first SPR wave. As a result, all of the reflected light incident on the total reflection mirror 620 is removed.

Fig. 7 is a diagram showing the configuration of the fourth embodiment of the optical isolator according to the present invention. The fourth embodiment of the optical isolator according to the present invention shown in FIG. 7 is modified to integrate the optical isolator of the auto structure shown in FIG. 5 into an on-chip by a semiconductor manufacturing process.

Referring to FIG. 7, the fourth embodiment 700 of the optical isolator according to the present invention includes a first incident waveguide 710, a total reflection element 720, a metal thin film 730, an emission waveguide 740, and a second incident wave. It consists of a waveguide 750 and a third incident waveguide 760. Since this embodiment is manufactured by a semiconductor manufacturing process, it is not necessary to include the supporting portion of the second embodiment of the optical isolator according to the present invention. In the fourth embodiment 700 of the optical isolator according to the present invention, the structure of the first incident waveguide 710, the total reflection element, the emission waveguide 740, the second incident waveguide 750, and the third incident waveguide 760 and Since the interconnection relationship is the same as that of the third embodiment 600 of the optical isolator according to the present invention described with reference to FIG. 6, the detailed description is omitted. However, the arrangement structure of the metal thin film 730 of the fourth embodiment 700 of the optical isolator according to the present invention is different from the third embodiment 600 of the optical isolator according to the present invention described with reference to FIG. This is explained in detail.

The metal thin film 730 is formed spaced apart from the rear surface of the total reflection element 720 by a predetermined distance. In this case, after depositing the intermediate layer to a thickness corresponding to the distance between the total reflection element 720 and the metal thin film 730 on the rear surface of the total reflection element 720, the metal thin film 730 is deposited, the method of removing the intermediate layer by etching The metal thin film 730 can be formed. Furthermore, when the intermediate layer is formed of a dielectric material having a refractive index lower than that of the first incident waveguide 710, there is an advantage in that the intermediate layer does not need to be removed. The second incident waveguide 750 and the third incident waveguide 760 are disposed in contact with the rear surface of the metal thin film 730.

When incident light having a specific wavelength is input to the entire surface of the total reflection element 720 through the first incident waveguide 710, the metal thin film is the same as the second embodiment 500 of the optical isolator according to the present invention illustrated in FIG. 5. Free electrons present on the front surface (ie, the surface opposite to the total reflection element 720) of 730 form a surface plasmon resonance wave. Therefore, the light energy reflected by the total reflection element 720 and output to the emission waveguide 740 is rapidly reduced under surface plasmon resonance conditions. In this state, when the first disturbing light is input through the second incident waveguide 750 formed in contact with the rear surface of the metal thin film 730, the group plasmon resonance condition is changed by affecting the collective vibration of electrons and thus the emission waveguide 740. The light energy reaching) is increased. As described above, the light is emitted from the emission waveguide 740 by the first disturbing light, and then, on the rear surface of the metal thin film 730 to remove the reflected light from the emission waveguide 740 toward the first incident waveguide 710. The second disturbing light, such as a laser, is incident on the rear surface of the metal thin film 730 through the third incident waveguide 760 in contact. When the surface plasmon resonance condition for the reflected light is satisfied by the second disturbing light, a surface plasmon resonance wave that travels in a direction opposite to the surface plasmon resonance wave generated by the incident light is generated along the front surface of the metal thin film 730, and thus As a result, the reflected light incident on the total reflection element 720 is removed.

As described above, the first to fourth embodiments of the optical isolator according to the present invention operate as an optical isolator by applying a separate disturbing light to satisfy the surface plasmon resonance with respect to the reflected light while the surface plasmon resonance condition is changed. Done. However, in the first to fourth embodiments of the optical isolator according to the present invention, the first disturbing light is applied so that incident light is directed to the output end, but the energy of the light output through the output end is considerably reduced compared to the energy of the incident light. have. Therefore, a configuration is needed to increase the light energy directed to the output stage. This can be done by connecting a separate amplifier to the output stage or by connecting the resonators to the input and output stages. Hereinafter, embodiments in which various types of resonators are connected to the input and output terminals of the third and fourth embodiments of the optical isolator according to the present invention will be described.

8 is a diagram showing the configuration of the fifth embodiment of the optical isolator according to the present invention. A fifth embodiment of the optical isolator according to the present invention combines a triangular resonator with a third embodiment of the optical isolator according to the present invention shown in FIG.

Referring to FIG. 8, the fifth embodiment 800 of the optical isolator according to the present invention includes a main waveguide 810, a resonant waveguide 820, total reflection elements 830, 832, and 834, a metal thin film 840, It consists of a first external waveguide 850 and a second external waveguide 860.

Incident light is input to one end of the main waveguide 810, and incident light reflected by the total reflection element 830 is output to the other end. In addition, a partial region of the main waveguide 810 forms an optical coupling region in which incident light input through the input terminal is coupled to the resonance waveguide 820. The resonant waveguide 820 includes a plurality of optical waveguides arranged in a triangular shape, and one optical waveguide among the optical waveguides forming three sides of the triangular resonant waveguide 820 is disposed in parallel with the main waveguide 810. In the optical waveguide disposed in parallel with the main waveguide 810, an optical coupling region is formed in which incident light that has been traveling around the resonance waveguide 820 is coupled to the main waveguide 810. The remaining two optical waveguides correspond to the first incident waveguide 610 and the emission waveguide 640 of the third embodiment of the optical isolator shown in FIG. 6. The total reflection elements 830, 832, and 834 are disposed in a vertex region that is a point where optical waveguides forming three sides of the triangular resonant waveguide 820 are connected to each other. Meanwhile, among the total reflection elements 830, 832, and 834 installed in the resonance waveguide 820, the optical waveguides disposed in parallel with the optical waveguides constituting the main waveguide 810 are disposed in the vertex region to which two other optical waveguides are connected. The metal thin film 840 is deposited on the rear surface of the total reflection element 830. Therefore, an angle formed by a normal perpendicular to the surface of the total reflection element 830 disposed at the vertex region to which each of the remaining two optical waveguides and the optical waveguides is connected must be a surface plasmon resonance angle to cause surface plasmon resonance.

In this state, the incident light input through the input terminal of the main waveguide 810 is optically coupled to the triangular resonance waveguide 820 through the optical coupling region, and is incident on the metal thin film 840 by the incident light input to the resonance waveguide 820. The free electrons present form a surface plasmon resonance wave. Therefore, the incident light input to the resonant waveguide 820 circulates in the resonant waveguide 820 such that there is no light output through the output terminal of the main waveguide 810. At this time, when the first disturbing light is incident on the rear surface of the metal thin film 840 through the first external waveguide 850, the surface plasmon resonance condition is changed by affecting the collective vibration of electrons. As a result, the optical coupling condition between the main waveguide 810 and the resonance waveguide 820 is changed to output light through the output terminal of the main waveguide 810.

As described above, the third incident waveguide is disposed in the same manner as the third embodiment of the optical isolator according to the present invention described with reference to FIG. 6 while the light is output from the output terminal of the main waveguide 810 by the first disturbing light. When the second disturbing light is incident on the rear surface of the metal thin film 840 through 860 to satisfy the surface plasmon resonance condition for the reflected light traveling in the opposite direction of the incident light that traverses the resonance waveguide 820, the metal thin film 840 A surface plasmon resonance wave is generated that runs along the front of the plane. Therefore, all of the reflected light in the resonance waveguide 820 is changed to the surface plasmon resonance wave, it is possible to remove the reflected light.

9 is a diagram showing the configuration of a sixth embodiment of an optical isolator according to the present invention. The sixth embodiment of the optical isolator according to the present invention combines a triangular resonator with the fourth embodiment of the optical isolator according to the present invention shown in FIG.

9, the sixth embodiment 900 of the optical isolator according to the present invention differs only from the position of the metal thin film 940 and the position where the surface plasmon resonance wave is generated. It is the same as the fifth embodiment 800 of the optical isolator according to the present invention described with reference to FIG. That is, the metal thin film 940 has two other optical waveguides except for the optical waveguides arranged in parallel with the optical waveguides constituting the main waveguide 910 among the total reflection elements 930, 932, and 934 installed in the resonance waveguide 920. It is deposited at a point spaced a certain distance from the rear surface of the total reflection element 930 disposed in the vertex region to be connected. The first external waveguide 950 and the second external waveguide 960 are disposed in contact with the rear surface of the metal thin film 940. At this time, in the state in which the light is output from the output terminal of the main waveguide 910 by the first disturbing light, the second arrangement is the same as the fifth embodiment 800 of the optical isolator according to the present invention described with reference to FIG. When the second disturbing light is incident on the rear surface of the metal thin film 940 through the external waveguide 960, a surface plasmon resonance wave traveling along the front surface of the metal thin film 940 is generated. Therefore, the reflected light in the resonant waveguide 920 is changed to the surface plasmon resonance wave, it is possible to remove the reflected light.

As described above, the fifth and sixth embodiments of the optical isolator according to the present invention described with reference to FIGS. 8 and 9 can minimize the amount of energy reduction of the output light to the input light by the triangular resonator. In addition, the fifth and sixth embodiments of the optical isolator according to the present invention described with reference to FIGS. 8 and 9 may be fabricated on-chip by photonic integrated circuit (PIC) technology on the same wafer. In the above description of the embodiments, the triangular resonant waveguide has been described as an example, but the shape of the resonant waveguide may be configured in various ways such as a circle and a rectangle. Furthermore, the resonator may be implemented in various forms. Hereinafter, embodiments in which the resonator of various forms are applied to the third embodiment of the optical isolator according to the present invention shown in FIG. 6 will be described. In this case, only the optical coupling principle of the resonator unit is described for convenience of description, and the remaining description is omitted. Resonators applied to the embodiments described below may also be applied to the fourth embodiment of the optical isolator according to the present invention illustrated in FIG. 7.

10 is a diagram showing the configuration of a seventh embodiment of an optical isolator according to the present invention. A seventh embodiment of the optical isolator according to the present invention has a structure in which a Mach-Zehnder electrooptic modulator is coupled to a third embodiment of the optical isolator according to the present invention shown in FIG. 6. The Mach-Gender electro-optic modulator is a structure in which two waveguides are arranged in parallel with each other, and the light incident on the input portion of the modulator made on the electro-optic material is merged into two pieces of light through two different waveguide paths. In this case, when a voltage is applied to one path, the refractive index changes in the portion, and thus light passing through the path causes a phase change to cause reinforcement or destructive interference with light passing through the other path.

Referring to FIG. 10, a seventh embodiment 1000 of an optical isolator according to the present invention is a light of one optical waveguide 1010 of two optical waveguides 1010 and 1015 constituting a Mach-gender electro-optic modulator. The resonance waveguide 1020 having the total reflection elements 1030, 1032, and 1034 disposed at each vertex in the coupling region is optically coupled. The incident light input to the input terminal of the Mach-Gender electro-optic modulator is merged into two pieces of light through two different optical waveguides 1010 and 1015 and then output to the output terminal. At this time, the incident light incident through the one optical waveguide 1010 is coupled to the optical waveguide constituting the resonant waveguide 1020 disposed in parallel with the optical waveguide 1010 is input to the resonant waveguide 1020. The branched light input to the resonant waveguide 1020 is reflected by the total reflection elements 1030, 1032, and 1034 disposed at the vertices of the resonant waveguide 1020, thereby circulating in the resonant waveguide 1020.

In this state, when the first disturbed light input through the first external waveguide 1050 is incident on the rear surface of the metal thin film 1040, the plasmon resonance condition is influenced by the collective vibration of electrons generated in the metal thin film 1040. Will change. As such, when the surface plasmon resonance condition is changed, the coupling condition of the optical waveguide 1010 constituting the shape of the Mach-gender electro-optic modulator to the resonance waveguide 1020 is changed. When the resonance condition is changed, the light coupled from the resonant waveguide 1020 to one optical waveguide 1010 constituting the form of a Mach-gender electro-optic modulator causes constructive or destructive interference with light passing through the other optical waveguide 1015. Light is output through the output of the gender electro-optic modulator. In this case, when the second disturbing light enters the rear surface of the metal thin film 1040 through the second external waveguide 1060, the reflected light in the resonance waveguide 1020 changes into a surface plasmon resonance wave which travels along the rear surface of the metal thin film 1040. It is possible to remove the reflected light.

Fig. 11 shows the construction of an eighth embodiment of an optical isolator according to the present invention.

Referring to FIG. 11, an eighth embodiment 1100 of an optical isolator according to the present invention includes a main waveguide 1110, an optical coupling unit 1120, a resonance waveguide 1130, and total reflection elements 1140, 1142, 1144, and 1146. ), A metal thin film 1150, a first external waveguide 1160, and a second external waveguide 1070.

An incident light is input to one end of the main waveguide 1110, and the incident light that is wound around the resonance waveguide 1130 is coupled to the main waveguide 1110 and then output to the other end. In addition, an optical coupling region in which the input incident light is coupled to the optical coupling unit 1120 is formed in the main waveguide 1110. The optical coupling unit 1120 distributes incident light input to one end of the main waveguide 1110 to the other end of the main waveguide 1110 and the resonance waveguide 1130. In addition, the optical coupling unit 1120 distributes the optical signal circulated in the resonance waveguide 1130 to the other end of the main waveguide 1110 and the resonance waveguide 1130. By constructing a multi-mode interference coupler (MMIC) using the self-imaging phenomenon by the optical coupling unit 1120, the size of the overall optical isolator can be reduced, and the optical coupling unit 1120 ) And other devices can be easily implemented on a single wafer.

The resonance waveguide 1130 has an optical coupling region that is optically coupled with the optical coupling unit 1120 to receive the branched light coupled to the resonance waveguide 1130 from the incident light input through one end of the main waveguide 1110, and has a plurality of optical coupling regions. An optical waveguide is arranged in a rectangular shape. In this case, one optical waveguide among the optical waveguides constituting four sides of the rectangular resonance waveguide 1130 is connected to the optical coupler 1120. The total reflection elements 1140, 1142, 1144, and 1146 are disposed in the vertex region, which is a point where the optical waveguides constituting the four sides of the rectangular resonance waveguide 1130 are connected to each other. Meanwhile, the total reflection element 1140 installed at one of the vertices of the total reflection mirrors 1140, 1142, 1144, and 1146 installed in the resonant waveguide 1130, except for the optical waveguide coupled to the optical coupling unit 1120, is connected to three other optical waveguides. ), A metal thin film 1150 is deposited.

When branched light having a specific wavelength is incident on the front surface of the total reflection element 1140 on which the metal thin film 1150 is deposited through the resonant waveguide 1130 at the surface plasmon resonance angle, free electrons present on the rear surface of the metal thin film 1150 Form a surface plasmon resonance wave. In this case, when the first disturbing light is incident on the rear surface of the metal thin film 1150 through the first external waveguide 1160, the first sway light affects the collective vibration of electrons generated in the metal thin film 1150, thereby changing the surface plasmon resonance condition. The optical coupling condition between the main waveguide 1110 and the resonant waveguide 1130 is changed by the changed surface plasmon resonance condition so that light is output through the other end of the main waveguide 1110. At this time, when the second disturbing light is incident on the rear surface of the metal thin film 1150 through the second external waveguide 1160, the reflected light in the resonance waveguide 1130 is changed into a surface plasmon resonance wave traveling along the rear surface of the metal thin film 1150. The reflected light can be removed.

The above-described embodiments generate a surface plasmon resonance wave on the metal film by incident light incident at the surface plasmon resonance angle so as not to generate an output light, thereby injecting a first disturbing light to the rear surface of the metal film from outside, thereby causing plasmon resonance. The optical isolators apply the principle of eliminating the reflected light traveling in the opposite direction to the incident light by causing the second light to enter the rear surface of the metal thin film from the outside after changing the condition. However, in contrast, the incident angle of the incident light incident on the total reflection element is configured to be close to the surface plasmon resonance angle (for example, the angle of incidence is set within a range of ± 5 ° to the surface plasmon resonance angle), and the rear surface of the metal thin film The optical isolator may be configured to remove the reflected light by satisfying the plasmon resonance condition for the reflected light incident by the disturbed light and traveling in the opposite direction to the incident light.

12 is a diagram showing the configuration of a ninth embodiment of an optical isolator according to the present invention.

Referring to FIG. 12, a ninth embodiment 1200 of an optical isolator according to the present invention is implemented in a Kretschmann structure, and includes a prism 1210, a metal thin film 1220, a first light input unit 1230, and a light. An output unit 1240 and a second light input unit 1250 are provided. The ninth embodiment 1200 of the optical isolator according to the present invention shown in FIG. 12 is characterized by the incident angle of the incident light and the disturbance light as compared with the first embodiment 200 of the optical isolator according to the present invention shown in FIG. 2. Only the input structure is different, the basic operation principle is the same. That is, the incident angle of the incident light is such that the angle deviates from the surface plasmon resonance angle with respect to the incident light (that is, the incident angle (θr) = surface plasmon resonance angle ± 5 °, provided that the incident angle (θr) ≠ surface plasmon resonance angle). The first light input unit 1230 is disposed. In addition, the surface plasmon for the reflected light is incident by entering the disturbing light to the rear surface of the metal thin film 1220 through the second light input unit 1250 disposed at the position facing the light output unit 1240 with respect to the metal thin film 1220. By satisfying the resonance condition, the reflected light is converted into a surface plasmon resonance wave traveling along the second surface of the metal thin film 1220.

FIG. 13 is a diagram showing the configuration of a tenth embodiment for an optical isolator according to the present invention.

Referring to FIG. 13, the tenth embodiment 1300 of the optical isolator according to the present invention has an auto structure, and includes a prism 1310, a metal thin film 1320, a support 1330, and a first light input unit. 1340, an optical output unit 1350, and a second optical input unit 1360. The tenth embodiment 1300 for the optical isolator according to the present invention shown in FIG. 13 is a comparison of the ninth embodiment 1200 for the optical isolator according to the present invention shown in FIG. 12. Only the location is different, the basic operation principle is the same. That is, the metal thin film 1320 is positioned to be spaced apart from the bottom surface of the prism 1310 to some extent, and the support 1330 is selectively provided on the second surface of the metal thin film 1320 to support the metal thin film 1320. do. In addition, the reflected light traveling in the opposite direction to the incident light by the disturbing light input through the second light input unit 1360 is converted into a surface plasmon resonance wave flowing on the first surface of the metal thin film 1320.

14 is a diagram showing the configuration of the eleventh embodiment of the optical isolator according to the present invention. An eleventh embodiment of the optical isolator according to the present invention is modified so that the optical isolator of the Crechmann structure shown in FIG. 12 can be integrated into an on-chip by a semiconductor manufacturing process.

Referring to FIG. 14, an eleventh embodiment 1400 of an optical isolator according to the present invention includes a first incident waveguide 1410, a total reflection element 1420, a metal thin film 1430, an emission waveguide 1440, and a second It consists of an incident waveguide 1450. Each waveguide consists of an optical signal transmission material such as an optical fiber or an optical waveguide.

One end of the first incident waveguide 1410 receives incident light through a light source or an optical path. The other end of the first incident waveguide 1410 is connected at a predetermined angle with respect to a normal line perpendicular to the front surface of the total reflection element 1420. At this time, the angle formed by the normal perpendicular to the surface of the first incident waveguide 1410 and the total reflection element 1420 is an angle deviated to some extent from the surface plasmon resonance angle (that is, the angle of incidence (θr) = surface plasmon resonance angle ± 5 °, However, the angle of incidence (θr) ≠ surface plasmon resonance angle) should be obtained. The metal thin film 1430 is formed on the rear surface of the total reflection element 1420. When incident light having a specific wavelength is input to the entire surface of the total reflection element 1420 through the first incident waveguide 1410, the total reflection is output by the total reflection element 1420 and output to the emission waveguide 1440. At this time, the reflected light toward the total reflection element 1420 is generated from the emission waveguide 1440, and the second incident waveguide disposed to face the emission waveguide 1440 on the basis of the metal thin film 1430 to remove the reflected light. 1450 is applied to the rear surface of the metal thin film 1430 to disturb the surface plasmon resonance conditions for the reflected light. When disturbed light is applied to the rear surface of the metal thin film 1430, the reflected light is changed into a surface plasmon resonance wave transmitted through the rear surface of the metal thin film 1430.

Fig. 15 shows the construction of a twelfth embodiment of an optical isolator according to the present invention. The twelfth embodiment of the optical isolator according to the present invention is modified to integrate the optical isolator of the auto structure shown in FIG. 13 into an on-chip by a semiconductor manufacturing process.

Referring to FIG. 15, a twelfth embodiment 1500 of an optical isolator according to the present invention includes a first incident waveguide 1510, a total reflection element 1520, a metal thin film 1530, an emission waveguide 1540, and a second incident light. A waveguide 1550 is provided. The twelfth embodiment 1500 of the optical isolator according to the present invention shown in FIG. 15 is compared with the eleventh embodiment 1400 of the optical isolator according to the present invention shown in FIG. 14. Only the location is different, the basic operation principle is the same. That is, the metal thin film 1530 is positioned to be spaced apart from the bottom surface of the total reflection element 1520 to some extent. In addition, the reflected light traveling in the opposite direction to the incident light by the disturbed light input through the second incident waveguide 1550 is converted into a surface plasmon resonance wave flowing on the first surface of the metal thin film 1530.

The ninth to twelfth embodiments of the optical isolator according to the present invention as described above are applied to the fifth to eighth embodiments of the optical isolator according to the present invention described with reference to Figs. By applying the resonator, the light energy directed to the output terminal can be increased.

Although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the specific preferred embodiments described above, and the present invention belongs to the present invention without departing from the gist of the present invention as claimed in the claims. Various modifications can be made by those skilled in the art, and such changes are within the scope of the claims.

1 is a view showing the configuration of a conventional optical isolator,

FIG. 2 shows a first embodiment of an optical isolator according to the invention using a Kretschmann structure, FIG.

FIG. 3 is a graph illustrating the calculation of light waves by finite difference time domain (FDTD) method when surface plasmon resonance is induced in a first embodiment of an optical isolator having a Kretschmann structure.

4A is a graph showing the progress of light waves after incident the first disturbing light onto the second surface of the metal thin film 220 when the surface plasmon resonance is induced in the first embodiment 200 of the optical isolator according to the present invention. ,

4B illustrates a third light input unit in a state where surface plasmon resonance conditions are changed by the first disturbing light in the first embodiment 200 of the optical isolator according to the present invention, and the light energy toward the light output unit 240 is increased. A graph showing the progress of the light waves after the second disturbing light is incident from 260,

FIG. 5 shows a second embodiment of an optical isolator according to the present invention using an Otto structure; FIG.

FIG. 6 is a view showing a third embodiment in which the first embodiment of the optical isolator according to the present invention shown in FIG. 2 is modified to be integrated on-chip by a semiconductor manufacturing process;

FIG. 7 is a view showing a fourth embodiment of the optical isolator according to the present invention, in which the second embodiment of the optical isolator according to the present invention is modified to be integrated into an on-chip by a semiconductor manufacturing process.

8 is a view showing a fifth embodiment of the optical isolator according to the present invention formed by coupling a triangular resonator to a third embodiment of the optical isolator according to the present invention;

9 is a view showing a sixth embodiment of the optical isolator according to the present invention formed by coupling a triangular resonator to a fourth embodiment of the optical isolator according to the present invention;

FIG. 10 shows a seventh embodiment of an optical isolator according to the present invention in which a Mach-Zehnder electrooptic modulator is coupled to a third embodiment of an optical isolator according to the present invention.

11 is a view showing an eighth embodiment of the optical isolator according to the present invention made by coupling an optical coupler to a third embodiment of the optical isolator according to the present invention;

12 shows a ninth embodiment of an optical isolator according to the present invention using a Crechmann structure;

FIG. 13 shows a tenth embodiment of an optical isolator according to the present invention using an auto structure;

FIG. 14 is a view showing an eleventh embodiment in which a ninth embodiment of the optical isolator according to the present invention shown in FIG. 12 is modified to be integrated on-chip by a semiconductor manufacturing process, and FIG.

FIG. 15 is a view showing a twelfth embodiment of the optical isolator according to the present invention, in which the tenth embodiment of the optical isolator according to the present invention is modified to be integrated on-chip by a semiconductor manufacturing process. .

Claims (23)

A total reflection element for total reflection of incident light input to the front surface; A metal film having a front surface disposed in contact with a rear surface of the total reflection element, and forming a surface plasmon resonance wave at the rear surface by incident light input at a surface plasmon resonance angle on the front surface of the total reflection element; A first incident waveguide disposed to form a normal line perpendicular to the front surface of the total reflection element and the plasmon resonance angle, and configured to allow the incident light input to one end to enter the front surface of the total reflection element; An emission waveguide disposed symmetrically with the first incident waveguide with respect to a normal line perpendicular to the front surface of the total reflection element, and outputting the incident light reflected from the total reflection element; A second incident waveguide for injecting a first disturbing light into a rear surface of the metal thin film to change the surface plasmon resonance condition formed by the incident light input at the surface plasmon resonance angle so that the incident light is output to the emission waveguide; And A third incident waveguide for removing the reflected light by satisfying a surface plasmon resonance condition for a reflected light traveling in a direction opposite to the incident light incident on the front surface of the total reflection element by injecting a second disturbing light into the rear surface of the metal thin film; Optical isolator using surface plasmon resonance, characterized in that. A total reflection element for totally reflecting the incident light input to the front surface; A metal thin film disposed to be spaced apart from the rear surface of the total reflection element by a incident light input at a surface plasmon resonance angle on the front surface of the total reflection element to form a surface plasmon resonance wave on a front surface opposite to the rear surface of the total reflection element; A first incident waveguide disposed to form a normal line perpendicular to the front surface of the total reflection element and the plasmon resonance angle, and configured to allow the incident light input to one end to enter the front surface of the total reflection element; An emission waveguide disposed symmetrically with the first incident waveguide with respect to a normal line perpendicular to the front surface of the total reflection element, and outputting the incident light reflected from the total reflection element; A second incident waveguide for injecting a first disturbing light into a rear surface of the metal thin film to change the surface plasmon resonance condition formed by the incident light input at the surface plasmon resonance angle so that the incident light is output to the emission waveguide; And A third incident waveguide for removing the reflected light by satisfying a surface plasmon resonance condition for a reflected light traveling in a direction opposite to the incident light incident on the front surface of the total reflection element by injecting a second disturbing light into the rear surface of the metal thin film; Optical isolator using surface plasmon resonance, characterized in that. The method according to claim 1 or 2, A main waveguide having an optical coupling region in which the incident light is input at one end and the incident light is output at the other end, and at least a portion of the incident light is split between the one end and the other end; And A resonant waveguide having an optical coupling region optically coupled with the optical coupling region of the main waveguide and receiving a branched optical signal branched from the main waveguide, wherein the plurality of optical waveguides are arranged in a polygonal shape; The first incident waveguide and the exiting waveguide are integrally formed with two first optical waveguides adjacent to each other among a plurality of optical waveguides constituting the resonance waveguide, Of the plurality of optical waveguides constituting the resonant waveguide, the branched light signal input to the resonant waveguide is totally reflected at a vertex region of the optical waveguide except for the first optical waveguide so that the branched light signal circulates in the resonance waveguide. Optical isolator using a surface plasmon resonance, characterized in that the total reflection element is disposed. The method according to claim 1 or 2, A main waveguide having an optical coupling region in which the incident light is input at one end and the incident light is output at the other end, and at least a portion of the incident light is split between the one end and the other end; An auxiliary waveguide disposed in parallel with the main waveguide, one end of which is optically coupled to one end of the main waveguide, and the other end of which is optically coupled to the other end of the main waveguide; And A resonant waveguide having an optical coupling region optically coupled with the optical coupling region of the main waveguide and receiving a branched optical signal branched from the main waveguide, and having a plurality of optical waveguides arranged in a polygonal shape; The first incident waveguide and the exiting waveguide are integrally formed with two first optical waveguides adjacent to each other among a plurality of optical waveguides constituting the resonance waveguide, Of the plurality of optical waveguides constituting the resonant waveguide, the branched light signal input to the resonant waveguide is totally reflected at a vertex region of the optical waveguide except for the first optical waveguide so that the branched light signal circulates in the resonance waveguide. Optical isolator using a surface plasmon resonance, characterized in that the total reflection element is disposed. The method according to claim 1 or 2, A main waveguide having an optical coupling region in which the incident light is input at one end and the incident light is output at the other end, and at least a portion of the incident light is split between the one end and the other end; A resonant waveguide having an optical coupling region optically coupled to the optical coupling region of the main waveguide and receiving a branched optical signal branched from the main waveguide, and having a plurality of optical waveguides arranged in a polygonal shape; And An optical coupling unit disposed in an optical coupling region of the main waveguide and the resonance waveguide and distributing the incident light input to one end of the main waveguide to the other end of the main waveguide and the resonance waveguide; The first incident waveguide and the exiting waveguide are integrally formed with two first optical waveguides adjacent to each other among a plurality of optical waveguides constituting the resonance waveguide, Of the plurality of optical waveguides constituting the resonant waveguide, the branched light signal input to the resonant waveguide is totally reflected at a vertex region of the optical waveguide except for the first optical waveguide so that the branched light signal circulates in the resonance waveguide. Optical isolator using a surface plasmon resonance, characterized in that the total reflection element is disposed. 3. The method of claim 2, An optical isolator using surface plasmon resonance, wherein a dielectric material having a refractive index lower than that of the first incident waveguide is disposed between the total reflection element and the metal thin film. The method according to claim 1 or 2, The second incidence waveguide is the first incidence waveguide with respect to a plane which bisects an angle between the first incidence waveguide and the outgoing waveguide so that the incidence direction of the first disturbing light coincides with the incidence direction of the incidence light to the total reflection element. Optical isolator using surface plasmon resonance, characterized in that arranged at an angle toward. The method according to claim 1 or 2, The third incident waveguide is angled toward the exit waveguide with respect to a plane that bisects an angle between the first incident waveguide and the exiting waveguide so that the incident direction of the second disturbing light coincides with the incident direction of the reflected light to the total reflection element. Optical isolator using surface plasmon resonance, characterized in that arranged in the form. A total reflection element for total reflection of incident light input to the front surface; A metal film having a front surface disposed in contact with a rear surface of the total reflection element, and forming a surface plasmon resonance wave at the rear surface by incident light input at a surface plasmon resonance angle on the front surface of the total reflection element; A first incident waveguide disposed to deviate from the normal line perpendicular to the front surface of the total reflection element and a predetermined angle with respect to the plasmon resonance angle, and to allow the incident light inputted at one end to the front surface of the total reflection element; An emission waveguide disposed symmetrically with the first incident waveguide with respect to a normal line perpendicular to the front surface of the total reflection element, and outputting the incident light reflected from the total reflection element; And A second incident waveguide for removing the reflected light by satisfying a surface plasmon resonance condition for the reflected light incident to the back surface of the metal thin film and traveling in a direction opposite to the incident light incident on the front surface of the total reflection element; Optical isolator using surface plasmon resonance. A total reflection element for total reflection of incident light input to the front surface; A metal thin film disposed to be spaced apart from the rear surface of the total reflection element by a incident light input at a surface plasmon resonance angle on the front surface of the total reflection element to form a surface plasmon resonance wave on a front surface opposite to the rear surface of the total reflection element; A first incident waveguide disposed to deviate from the normal line perpendicular to the front surface of the total reflection element and a predetermined angle with respect to the plasmon resonance angle, and to allow the incident light inputted at one end to the front surface of the total reflection element; An emission waveguide disposed symmetrically with the first incident waveguide with respect to a normal line perpendicular to the front surface of the total reflection element, and outputting the incident light reflected from the total reflection element; And A second incident waveguide for removing the reflected light by satisfying a surface plasmon resonance condition for the reflected light incident to the back surface of the metal thin film and traveling in a direction opposite to the incident light incident on the front surface of the total reflection element; Optical isolator using surface plasmon resonance. The method according to claim 9 or 10, A main waveguide having an optical coupling region in which the incident light is input at one end and the incident light is output at the other end, and at least a portion of the incident light is split between the one end and the other end; And A resonant waveguide having an optical coupling region optically coupled with the optical coupling region of the main waveguide and receiving a branched optical signal branched from the main waveguide, and having a plurality of optical waveguides arranged in a polygonal shape; The first incident waveguide and the exiting waveguide are integrally formed with two first optical waveguides adjacent to each other among a plurality of optical waveguides constituting the resonance waveguide, Of the plurality of optical waveguides constituting the resonant waveguide, the branched light signal input to the resonant waveguide is totally reflected at a vertex region of the optical waveguide except for the first optical waveguide so that the branched light signal circulates in the resonance waveguide. Optical isolator using a surface plasmon resonance, characterized in that the total reflection element is disposed. The method according to claim 9 or 10, A main waveguide having an optical coupling region in which the incident light is input at one end and the incident light is output at the other end, and at least a portion of the incident light is split between the one end and the other end; An auxiliary waveguide disposed in parallel with the main waveguide, one end of which is optically coupled to one end of the main waveguide, and the other end of which is optically coupled to the other end of the main waveguide; And A resonant waveguide having an optical coupling region optically coupled with the optical coupling region of the main waveguide and receiving a branched optical signal branched from the main waveguide, wherein the plurality of optical waveguides are arranged in a polygonal shape; The first incident waveguide and the exiting waveguide are integrally formed with two first optical waveguides adjacent to each other among a plurality of optical waveguides constituting the resonance waveguide, Of the plurality of optical waveguides constituting the resonant waveguide, the branched light signal input to the resonant waveguide is totally reflected at a vertex region of the optical waveguide except for the first optical waveguide so that the branched light signal circulates in the resonance waveguide. Optical isolator using a surface plasmon resonance, characterized in that the total reflection element is disposed. The method according to claim 9 or 10, A main waveguide having an optical coupling region in which the incident light is input at one end and the incident light is output at the other end, and at least a portion of the incident light is split between the one end and the other end; A resonant waveguide having an optical coupling region for receiving a branched optical signal branched from the main waveguide, and having a plurality of optical waveguides arranged in a polygonal shape; And An optical coupling portion optically coupled to the optical coupling region of the main waveguide and the optical coupling region of the resonance waveguide, respectively, to distribute the incident light input to one end of the main waveguide to the other end of the main waveguide and the resonance waveguide; Include, The first incident waveguide and the exiting waveguide are integrally formed with two first optical waveguides adjacent to each other among a plurality of optical waveguides constituting the resonance waveguide, The branched optical signal is circulated in the resonance waveguide by reflecting the branched optical signal input to the resonance waveguide in a vertex region of the plurality of optical waveguides constituting the resonance waveguide, except for the first optical waveguide. Optical isolator using a surface plasmon resonance, characterized in that the total reflection element is disposed. The method of claim 10, An optical isolator using surface plasmon resonance, wherein a dielectric material having a refractive index lower than that of the first incident waveguide is disposed between the total reflection element and the metal thin film. The method according to claim 9 or 10, The second incident waveguide forms an angle toward the emission waveguide with respect to a plane that bisects an angle between the first incident waveguide and the emission waveguide so that the incident direction of the disturbed light coincides with the incident direction of the reflected light to the total reflection element. An optical isolator using surface plasmon resonance characterized in that the arrangement. A total reflection element that totally reflects incident light input to the first surface; A metal thin film having a front surface disposed in contact with the first surface of the total reflection element, and forming a surface plasmon resonance wave at the rear surface by incident light input at a surface plasmon resonance angle on the front surface of the total reflection element; A normal line perpendicular to the first surface of the total reflection element by entering the incident light input to the second surface of the total reflection element, the incident light incident on the second surface of the total reflection element proceeds inside the total reflection element A first light input unit arranged to be incident on a second surface of the total reflection element while forming the plasmon resonance angle; The incident light is disposed to be symmetrical with the first light input unit with respect to a normal line perpendicular to the first surface of the total reflection element, and is reflected by the first surface of the total reflection element and exits the incident light emitted through the third surface of the total reflection element. An optical output unit for receiving the output through the other end; A second light input unit configured to change a surface plasmon resonance condition formed by incident light input to the surface plasmon resonance angle by injecting a first disturbing light into a rear surface of the metal thin film so that the incident light is output to the light output unit; And And a third light input unit configured to remove the reflected light by satisfying a surface plasmon resonance condition for the reflected light traveling in a direction opposite to the incident light incident on the front surface of the total reflection element by injecting a second disturbing light into the rear surface of the metal thin film. Optical isolator using surface plasmon resonance, characterized in that. A total reflection element that totally reflects incident light input to the first surface; A surface plasmon resonance wave is disposed on the first surface of the total reflection element and spaced apart from the first surface by a incident light input at a surface plasmon resonance angle on the front surface of the total reflection element. Metal thin film to form; A normal line perpendicular to the first surface of the total reflection element by entering the incident light input to the second surface of the total reflection element, the incident light incident on the second surface of the total reflection element proceeds inside the total reflection element A first light input unit arranged to be incident on a second surface of the total reflection element while forming the plasmon resonance angle; The incident light is disposed to be symmetrical with the first light input unit with respect to a normal line perpendicular to the first surface of the total reflection element, and is reflected by the first surface of the total reflection element and exits the incident light emitted through the third surface of the total reflection element. An optical output unit for receiving the output through the other end; A second light input unit configured to change a surface plasmon resonance condition formed by incident light input to the surface plasmon resonance angle by injecting a first disturbing light into a rear surface of the metal thin film so that the incident light is output to the light output unit; And And a third light input unit configured to remove the reflected light by satisfying a surface plasmon resonance condition for the reflected light traveling in a direction opposite to the incident light incident on the front surface of the total reflection element by injecting a second disturbing light into the rear surface of the metal thin film. Optical isolator using surface plasmon resonance, characterized in that. A total reflection element that totally reflects incident light input to the first surface; A metal thin film having a front surface disposed in contact with the first surface of the total reflection element, and forming a surface plasmon resonance wave at the rear surface by incident light input at a surface plasmon resonance angle on the front surface of the total reflection element; A first light input unit arranged to deviate from a normal angle perpendicular to the front surface of the total reflection element and a predetermined angle with respect to the plasmon resonance angle, and incident the incident light input to one surface to the front surface of the total reflection element; An optical output unit arranged to be symmetrical with the first light input unit with respect to a normal line perpendicular to the front surface of the total reflection element, and outputting the incident light reflected from the total reflection element; And And a second light input unit configured to remove the reflected light by satisfying a surface plasmon resonance condition for the reflected light incident to the rear surface of the metal thin film and traveling in a direction opposite to the incident light incident on the front surface of the total reflection element. Optical isolator using surface plasmon resonance. A total reflection element that totally reflects incident light input to the first surface; A surface plasmon resonance wave is disposed on the first surface of the total reflection element and spaced apart from the first surface by a incident light input at a surface plasmon resonance angle on the front surface of the total reflection element. Metal thin film to form; A first light input unit arranged to deviate from a normal angle perpendicular to the front surface of the total reflection element and a predetermined angle with respect to the plasmon resonance angle, and incident the incident light input to one surface to the front surface of the total reflection element; An optical output unit arranged to be symmetrical with the first light input unit with respect to a normal line perpendicular to the front surface of the total reflection element, and outputting the incident light reflected from the total reflection element; And And a second light input unit configured to remove the reflected light by satisfying a surface plasmon resonance condition for the reflected light incident to the rear surface of the metal thin film and traveling in a direction opposite to the incident light incident on the front surface of the total reflection element. Optical isolator using surface plasmon resonance. The method according to claim 16 or 17, The second light input unit is configured to bisect the angle between the first light input unit and the light output unit so that the incident direction of the first disturbing light coincides with the incident direction of the incident light to the total reflection element. Optical isolator using surface plasmon resonance, characterized in that arranged at an angle toward the input. The method according to claim 16 or 17, The third light input unit is arranged in two directions such that the angle between the first light input unit and the light output unit is bisected so that the incident direction of the second disturbing light coincides with the incident direction of the reflected light to the total reflection element. Optical isolator using surface plasmon resonance, characterized in that arranged at an angle toward. The method of claim 18 or 19, The second light input part is angled toward the light output part with respect to a plane that bisects an angle between the first light input part and the light output part so that the incident direction of the disturbed light coincides with the incident direction of the reflected light to the total reflection element. Optical isolator using surface plasmon resonance, characterized in that arranged in the form. The method according to any one of claims 16 to 19, The total reflection element is an optical isolator using surface plasmon resonance, characterized in that the prism.

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