KR100200847B1 - Optics power device with monitoring detector - Google Patents

Abstract

An optical output device employing a monitor photodetector comprising a substrate, a light source integrated on the substrate and generating and emitting light, and a monitor photodetection means provided around the apparatus so as to receive a part of the amount of light emitted from the light source. Is disclosed.

The disclosed optical output device includes diffraction means positioned on the optical axis of the emitted light to diffract light emitted from the light source into at least three light as the light detection means, and light for the monitor which receives some of the light diffracted by the diffraction means. And a detector. Therefore, the characteristics of the light emitted from the light source and precise light amount control are possible.

Description

Optical output device adopting monitor photodetector

1 is a schematic perspective view of one embodiment of an optical output device employing a conventional photodetector for a monitor.

2 is a schematic perspective view of another type of optical output device employing a conventional photodetector for a monitor.

3 is a side sectional view showing a first embodiment of an optical output device employing a photodetector for a monitor according to the present invention;

4 is a side sectional view showing a second embodiment of an optical output device employing a photodetector for a monitor according to the present invention;

Fig. 5 is a side sectional view showing a third embodiment of an optical output device employing a photodetector for a monitor according to the present invention.

6 is a side sectional view showing a fourth embodiment of an optical output device employing a photodetector for a monitor according to the present invention;

7 is a side sectional view showing a fifth embodiment of an optical output device employing a photodetector for a monitor according to the present invention;

8 is a side sectional view showing a sixth embodiment of an optical output device employing a photodetector for a monitor according to the present invention;

* Explanation of symbols for main parts of the drawings

20: substrate 20, 40: light source

24, 25: diffraction means 26: monitor photodetector

27: projection window 28: housing

30: reflector

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical output device employing a monitor photodetector, and more particularly, to a monitor photodetector made of an edger diode in which a monitor photodetector is improved to receive a part of the amount of light emitted from a light source. An optical output device.

In general, an optical output device employing an edge-emitting laser as a light source is one of the light emitted from the light source in the bidirectional direction used for its original function, and receives the light emitted in the other direction is emitted from the light source It was used as a means of controlling the amount of emitted light. In this case, the amount of light emitted in both directions from the light source is not necessarily proportional, and there is a problem in that the light output changes due to temperature change.

In addition, when a surface light laser (SEL) is used as a light source as a light output device, unlike a light source using an edge emitting laser, light is emitted in a vertical direction with respect to the stacked stack of semiconductor materials. . The light emitted in the vertical direction is close to circular light and has a high light density. Since the light source using this surface light laser and the photodetector which is an information detection means for the error signal among the optical signals detected using the light emitted from this light source can be integrated on the same board | substrate, it can be used for optical, such as an optoacoustic apparatus and a computer communication apparatus. It is attracting attention in the field of application. However, the light source using the surface light laser is different from the conventional light source using the edge-emitting laser light, the light is emitted in a direction perpendicular to the substrate, and one surface of the light emitting surface is coupled to the semiconductor substrate, so the photodetector for the monitor Countermeasures for the installation should be sought.

1 is a schematic perspective view of one embodiment of an optical output device employing a conventional photodetector for a monitor. The structure and principle of operation will be described with reference to this figure.

An optical output device employing the monitor photodetector includes a semiconductor light source (3) and a light source (3) which is a surface light laser including electrical means such as application of a forward bias voltage to emit light integrated on the substrate (1). And a photodetector for monitor 5 comprising a surface light laser comprising an annular shape and an electrical means to which a reverse bias voltage or voltage is not applied so as to absorb the self-emission emitted from the side of the light source 3. )

The photodetector 5 absorbs the differential light emitted from the light source 3, converts the light into an electrical signal, and feeds back to the electrode constituting the light source 3 to control the amount of light. However, the relationship between the self-emission emitted to the side and the amount of light emitted vertically varies not only with temperature, but also the emission amount is significantly smaller than that of the vertical emitted light, and the absorption rate of the side self-emission through the photodetector of the emitted self-emission Since this is not good, there is a difficulty in using it as a signal for controlling the amount of vertical divergent light.

2 is a schematic perspective view of another embodiment of an optical output device employing a conventional photodetector for a monitor.

The optical output device employing the photodetector for the monitor includes a semiconductor substrate 11, a light source 13 made of a surface light laser formed on the substrate 11, and an upper surface of the light source 13. It consists of the monitor photodetector 15 which monitors the quantity of light emitted from (13). The photodetector 15 is provided on the upper surface of the light source 13 in a predetermined thickness so as to absorb some incident light and transmit the remaining light. At this time, the light for the monitor is detected using the absorbed light. In this case, the amount of light detected for the monitor is sufficient, and there is no problem in performing its function. However, the amount of light that passes through the monitor and enters the optical recording / reproducing medium is reduced, and noise is generated by light that is reincident from the outside. There was.

Accordingly, an object of the present invention is to improve the efficiency and the efficiency of the light emitted for the original function, and to improve the efficiency of the light received through the monitor photodetector to overcome the disadvantages as described above.

The present invention to achieve the above object,

An optical output device employing a monitor photodetector comprising a substrate, a light source integrated on the substrate and generating and outputting light, and a monitor photodetection means provided therein so as to receive a portion of the amount of light emitted from the light source. To

The light detecting means includes diffraction means positioned on an optical axis of the emitted light so as to diffract the light emitted from the light source into at least three lights, and a photodetector for monitor that receives some of the light diffracted by the diffraction means. It is characterized by.

Hereinafter, with reference to the accompanying drawings will be described embodiments of the present invention;

3 is a side sectional view showing a first embodiment of an optical output device employing a photodetector for a monitor according to the present invention.

As shown, the light output device includes a substrate 20, a light source 22 positioned on the substrate 20, diffraction means 24 for diffracting the light emitted from the light source 22, and the diffraction. It is roughly classified as a photodetector 26 which receives a portion of the light diffracted in the means 24.

The light source 22 is fixed to the mount 21, which is fixed to the substrate 20 by a corner emission laser, and serves as a heat sink. A part of the light 22a which is emitted upward from the light 22a and 22b emitted from both light sources 22 is used by an optical pickup device of the scanning device, etc., and receives the remaining part of the light to be emitted from the light source. Adjust the amount of light

The diffraction means 24 is arranged on the optical axis of the light source 22, and diffracts the incident light 22a into at least three lights, such as zero order diffracted light and ± first order diffracted light. Of the diffracted light, zero-order light is used for its original function, and rotational ± 1-order light is used for the monitor. Here, the diffraction means 24 is composed of a diffraction grating having a predetermined diffraction pattern formed on at least one surface thereof. The diffraction means 24 itself is conventional in the field of optical applications, and the detailed description thereof is well illustrated in pages 424 to 434 of HECHT OPTICS (2nd Edition).

The light source 22 and the diffraction means 24 are enclosed in a housing 28 through which light can pass through the light exit surface.

The photodetector 26 is formed on the inner wall around the projection window 27 of the housing 28 to receive the diffracted light emitted from the light source 22 and diffracted by the diffraction means 24. It is preferable that two monitor photodetectors 26 are provided and disposed on both sides of the projection window, respectively, to receive the + 1st diffraction light and the -1st diffraction light diffracted by the diffraction means 24, respectively. The monitor photodetector 26 is a conventional photodetector that receives incident light and photoelectrically converts the incident light. The monitor photodetector 26 itself is well known in the field of optical applications, and is well represented on pages 205 to 210 of the November 1989 issue of electronic components.

In this way, the light output of the light source 22 can be accurately controlled by receiving light proportional to the light used for its original function in the light source 22 through the monitor photodetector 26. Of course, a light output control circuit (not shown) is provided between the photodetector 26 and the light source 22.

The see-through window 27 is a general name for all materials that are transmitted in a straight line and diffraction-transmitted with respect to incident light. That is, it may be made of a material such as glass, transparent plastic.

In particular, the hologram device may be a hologram device configured to vary a direction of light emitted from the light source and a transmission direction of light reflected and incident from the outside thereof. When the hologram element is employed, the reflected light can be prevented from being returned to the light source, so that the light emitted from the light source is not affected by the reflected light. In addition, an error signal can be detected by receiving light diffracted by the hologram element without employing a beam splitter.

4 is a side sectional view showing a second embodiment of an optical output device employing a photodetector for a monitor according to the present invention.

As mentioned through the first embodiment, the optical output device includes a substrate 20, a light source 22 fixed on the substrate 20 and emitting light in both corner directions, and in this light source 22 Diffraction means 24 for diffracting the emitted light, and a projection window which surrounds the light source 22 and the diffraction means 24 and transmits a part of the light 22a emitted from the light source 22 ( And a housing 28 having a 27, and a photodetector 26 for a monitor formed inside the housing 28. Here, the members having the same function as those mentioned in the first embodiment used the same reference numerals as those shown in FIG.

As shown, the photodetector 26 is formed on the same substrate 20 as the light source 22, and the photodetector 26 receives a portion of the light diffracted by the diffraction means 24. In order to form the reflector 30 at a predetermined position on the inner surface of the housing. A planar mirror may be used as the reflector 30, and a concave mirror configured to collect light to the photodetector 26 may be used.

When the photodetector 26 is formed on the substrate 20 as described above, the design of the light output control circuit (not shown) formed between the light source 22 and the photodetector 26 is easy.

Of course, the projection window 27 may be a hologram element as described above.

5 is a side sectional view showing a third embodiment of an optical output device employing a monitor photodetector according to the present invention.

As shown in the figure, a light source 40 made of a surface light laser integrated on the substrate 20, diffraction means 24 for diffracting the light 40a emitted from the light source 40, and the diffraction means 24 ) Is roughly classified into a photodetector for monitor 26 that receives light diffracted by The light source 40, diffraction means 24 and photodetector 26 are also enclosed in a housing 28 having a projection window 27.

The light source 40 includes at least one P-type reflector layer 43 and an N-type reflector layer 47, and an active region 47 is formed between the reflector layers 43 and 47. At both ends, a first electrode layer 41 made of a p-type or n-type metal layer and a second electrode layer 49 made of a metal layer of a different type from the first electrode layer 41 are formed. The forward bias voltage is applied to the first and second electrode layers 41 and 49 of the light source 40 to be driven. The high-density laser light close to circular light is emitted in the vertical direction by the voltage applied in this way. The reflectance of the P-type reflector layer 43 is designed to be lower than that of the N-type reflector layer 47 so that most of the emitted light is emitted to the upper surface.

The housing 28 is formed in a portion in which the projection window 27 facing the light source 40 to direct the light emitted from the light source 40 in the vertical direction to the outside. This projection window 27 is a generic term for all materials which are subjected to straight transmission and diffraction transmission with respect to incident light. That is, it may be made of a material such as glass, transparent plastic. In particular, the hologram device may be a hologram device configured to vary a direction of light emitted from the light source 40 and a transmission direction of light reflected and reflected from the outside thereof. When the hologram element is employed, the reflected light can be prevented from being returned to the light source 40, so that the light emitted from the light source 40 is not affected by the reflected light.

The diffraction means 24 are arranged on the optical axis between the light source 40 and the housing 28 to diffract the light emitted from the light source 40 into at least zero order and ± first order diffracted light. The zero-order diffracted light diffracted through this diffraction means 28 is used for its original function, and the diffracted ± first-order diffracted light is used to adjust the light output of the light source 40 toward the photodetector.

The photodetector 26 is formed inside the periphery of the projection window 27 of the housing 28 and includes at least one of diffraction light and +1 order diffraction light diffracted by the diffraction means 24. It is supposed to receive light. Preferably, the photodetectors 26 are provided in pairs to receive + 1st diffraction light and -1st diffraction light, respectively, for use in monitors.

Therefore, when the surface light laser is used as the light source, the light characteristics of the emitted light can be improved by receiving light proportional to the light output and adjusting the light output.

6 is a side sectional view showing a fourth embodiment of an optical output device employing a photodetector for a monitor according to the present invention.

As mentioned through the third embodiment, the light source 40 of the surface light laser and the light emitted from the light source 40 to diffract the light emitted from the light source 40 into at least three lights Diffraction means 24 disposed on the optical axis of 40a, a monitor photodetector 26 for receiving light diffracted by the diffraction means 24, the light source 40 and diffraction means 24; And a housing 28 enclosing the photodetector 26 and having a projection window 27.

The monitor photodetector 26 is located on the same substrate 20 as the light source 40 and is diffracted by the diffraction means 24 at a predetermined position on the inner surface around the projection window 27 of the housing 28. It was further provided with a reflector 30 for directing the light to the monitor photodetector 26. The reflector 30 may be a planar mirror, or may be a concave mirror configured to focus the ± diffraction light diffracted by the diffraction means 24 on the photodetector 26.

The monitor photodetector 26 may be provided with a weight, and receives + 1st diffraction light and -1st diffraction light, respectively. This received light is proportional to the amount of light passing through the projection window 27.

The photodetector 26 may be a conventional light receiving element, but preferably a surface light laser. In the case of employing this surface light laser, light is received by providing reverse bias voltages to the electrode layers formed on the upper and lower surfaces, or by electrical means for applying no voltage.

When the monitor photodetector is provided on the same substrate as described above, the arrangement of the light output control circuit for controlling the light source from the information received by the photodetector is easy.

7 is a side sectional view showing a fifth embodiment of an optical output device employing a photodetector for a monitor according to the present invention.

As shown, it is composed of a light source 40, a housing 28, a photodetector 26 and a diffraction means 24. The light source 40, the housing 28, and the photodetector 26 follow the fourth embodiment mentioned through FIG. 5.

The diffraction means 24 is formed on the light exit surface of the light source 40. That is, the diffraction pattern was formed to replace the diffraction means 24 employed as a separate member.

The diffraction pattern is formed through etching or deposition on the light exit surface of the surface light laser. In particular, when forming a diffraction pattern through vapor deposition, it is preferable to deposit an oxide film such as SiO ₂ .

Therefore, the structure of the optical output device employing the monitor photodetector 26 can be simplified, and the amount of light emitted from the light source 40 can be accurately monitored.

8 is a side sectional view showing a sixth embodiment of an optical output device employing a monitor photodetector according to the present invention.

As shown, it is composed of a light source 40, a housing 28, a photodetector 26 and a diffraction means 24. The light source 40, the housing 28, and the photodetector 26 follow the fifth embodiment mentioned through FIG. 6.

The diffraction means 24 is formed on the light exit surface of the light source 40. That is, the diffraction pattern 30 was formed to replace the diffraction means 24 employed as a separate member.

The diffraction pattern is formed through etching or deposition on the light exit surface of the surface light laser.

Therefore, the arrangement of the light output control circuit provided between the photodetector and the light source can be facilitated, and the structure thereof can be simplified by forming the diffraction means integrally.

The optical output device employing the photodetector for the monitor made in this way is a very useful invention that can be applied to various optical applications such as optical recording / reproducing apparatus, optical communication, computer system, etc., because the characteristics of the emitted light and precise light quantity control are possible. .

Claims (6)

A photo-sensing device comprising a substrate, a light source integrated on the substrate and generating and outputting light, and a light detecting means for monitor provided around the light source to receive a part of the amount of light emitted from the light source. Diffraction means positioned on an optical axis of the emitted light so as to diffract light emitted from the light source into at least three lights; And a monitor photodetector for receiving a part of light diffracted by the diffraction means. The monitor photodetector of claim 1, further comprising a projection window through which light emitted from the light source passes, and a housing configured to surround the light source, a photodetector for monitoring, and diffraction means. Light output device which we adopted. The monitor according to claim 2, wherein the photodetector is disposed on the same substrate as the light source, and further includes a reflector on the inner surface of the housing to direct the light diffracted by the diffraction means to the photodetector. Optical output device employing photodetector. 3. An optical output device employing a photodetector for a monitor according to claim 2, wherein the projection window of said housing is a hologram element in which a diffraction pattern is formed in a predetermined direction. The photodetector for a monitor according to claim 1, wherein the light source is a surface light laser configured to emit light in a direction perpendicular to the laminated structure, and the diffraction means is located on an optical axis of the light emitted from the surface light laser. Light output device which adopted. The monitor of claim 1, wherein the light source is a surface light laser configured to emit light in a direction perpendicular to the laminated structure, and the diffraction means is integrally formed on the light exit surface of the surface light laser. Light output device which we adopted.