CN115469398A - Array waveguide grating with input port of asymmetric conical structure and communication device - Google Patents

Abstract

The invention discloses an arrayed waveguide grating with an asymmetric conical structure as an input port and a communication device, wherein the arrayed waveguide grating comprises a first input waveguide, a first free propagation region, an arrayed waveguide, a second free propagation region and a second output waveguide which are connected in sequence; the second output waveguide is connected with the second free propagation region through the second output port conical structure; the second free propagation region is connected with the array waveguide through a second array waveguide tapered port; the arrayed waveguide is connected with the first free propagation region through a first arrayed waveguide tapered port; the first input wave passes through the first input port conical structure to input the light source into a first free propagation region in a non-central region of a Rowland circle; the first input port tapered structure is an asymmetric tapered structure. The invention can improve the light-emitting uniformity of each channel of the arrayed waveguide grating with the port of the incident light source positioned at the center of the non-Rowland circle, namely improve the loss uniformity among output channels.

Description

Arrayed waveguide grating and communication device whose input port is an asymmetric tapered structure

technical field

The invention belongs to the field of waveguide technology, and in particular relates to an arrayed waveguide grating and a communication device whose input port is an asymmetric tapered structure.

Background technique

Optical interconnect technology has significant advantages in applications such as ultra-high speed, ultra-large capacity, ultra-long transmission distance and ultra-low crosstalk. At present, the direction of optical interconnection is mainly developing towards higher integration density and shorter transmission distance, and arrayed waveguide grating (Arrayed Waveguide Grating, AWG), as an important filter device based on planar waveguide integration technology, is based on photon It has a wide application value in the field of integrated technology.

The arrayed waveguide grating is mainly composed of a free propagation area composed of a slab waveguide, an array waveguide, and an input-output waveguide. It has the advantages of compact structure, small insertion loss, wide coverage band, and simple manufacturing process. Its working principle is: after the wide-spectrum optical signal is introduced into the free propagation area formed by the slab waveguide from the input port, the optical field is gradually broadened by diffraction and finally coupled into the arrayed waveguide. Since the lengths of the arrayed waveguides are arranged in an arithmetic sequence, the light coupled in produces an optical path difference between different arrayed waveguides, and thus the phase of the light at the output end of the arrayed waveguide is also distributed in an arithmetic sequence. The refractive index of light of different wavelengths is different when it is transmitted in the arrayed waveguide grating, so its phase difference is a function of wavelength. Optical signals with different phase differences will be interfered and superimposed at different positions of the Rowland arc after entering the free propagation area again, and light waves of the same wavelength will converge to the same position of the Rowland arc, which can be used as the port of the corresponding output waveguide.

The loss uniformity of the output light of each channel is an important indicator of the performance of the arrayed waveguide grating. For the traditional incident light source port position at the central point of the Rowland circle, the spectral response of the arrayed waveguide grating is Gaussian, and its 3dB bandwidth is usually only about 40% of the channel spacing. In order to optimize the uniformity of light output, a wide half-width of the peak can be obtained by combining the arrayed waveguide grating with other filter elements, such as Mach-Zehnder interferometer and arrayed waveguide grating cascade, or design a multi-mode interference structure at the input port ( Multiple-mode interference, MMI) to form high-order mode components to optimize the spectral shape. However, cascading other filtering elements often reduces the integration of the device. When using MMI, the width of MMI may be affected by the width of the input/output waveguide interval, which is reflected in the arrayed waveguide grating at the edge of the incident light source port. more obvious.

For the AWG whose incident light source port is not at the center of the Rowland circle and the light source is incident obliquely to the port, its spectral response is not Gaussian, and its light field distribution exhibits asymmetric characteristics at the receiving plane of the array waveguide. The asymmetric light field distribution can lead to the asymmetric characteristics of the spectral response of the arrayed waveguide grating output, which seriously affects the uniformity of the light emitted by each channel of the arrayed waveguide grating, and it is reflected in the output spectrum that the output spectrum intensity of different channels is large. difference.

Contents of the invention

In order to solve the deficiencies in the prior art, the purpose of the present invention is to provide an arrayed waveguide grating and a communication device with an input port of an asymmetric tapered structure, which can improve the performance of each channel of the arrayed waveguide grating with the port of the incident light source located at the center of the non-Rowland circle. The uniformity of light output, that is, to improve the uniformity of coupling loss.

In order to achieve the above object, the technical scheme adopted in the present invention is:

In the first aspect, there is provided an arrayed waveguide grating whose input port is an asymmetric tapered structure, comprising: a first input waveguide, a first free propagation region, an array waveguide, a second free propagation region and a second output waveguide connected in sequence; The second output waveguide is connected to the second free propagation area through the tapered structure of the second output port; the second free propagation area is connected to the array waveguide through the second array waveguide tapered port; the array waveguide The tapered port of the first arrayed waveguide is connected to the first free propagation area; the first input waveguide inputs the light source into the first free propagation area in the non-central area of the Rowland circle through the tapered structure of the first input port; The tapered structure of the first input port is an asymmetric tapered structure, including a symmetrical trapezoidal structure connected with the first input waveguide, and a trapezoidal structure connected with the symmetrical trapezoidal structure and the first free propagation area.

Further, the trapezoidal structure is decomposed into a rectangle connected with a symmetrical trapezoidal structure and right-angled triangles located on both sides of the rectangle, wherein the side length of the side of the right-angled triangle away from the center of the Rowland circle on the first free propagation area is greater than The side length of the side of the right triangle near the center of the Rowland circle on the first free propagation area.

Further, the trapezoidal structure is decomposed into a first right-angled trapezoid connected with a symmetrical trapezoidal structure and right-angled triangles located on both sides of the first right-angled trapezoid, wherein the hypotenuse of the first right-angled trapezoid is connected with the symmetrical trapezoidal structure, away from The side length of the right-angled triangle at the center of the Rowland circle on the first free propagation area is longer than the side length of the side of the right-angled triangle near the center of the Rowland circle on the first free propagation area.

Further, the trapezoidal structure is decomposed into a second right-angled trapezoid connected to the symmetrical trapezoidal structure and a right-angled triangle located on one side of the second right-angled trapezoid, wherein the long right-angled side of the second right-angled trapezoid is connected to the symmetrical trapezoidal structure, A right triangle is a right triangle that is far from the center of the Rowland circle.

Further, the trapezoidal structure is decomposed into a quadrilateral with a right angle connected to a symmetrical trapezoidal structure and a right triangle located on one side of the quadrilateral with a right angle, wherein the right triangle is a right triangle away from the center of the Rowland circle.

Further, the arrayed waveguide grating is a single-port input-multiple-output arrayed waveguide grating, a multi-port input-multiple-output arrayed waveguide grating, a reflective arrayed waveguide grating or a symmetrical arrayed waveguide grating.

Further, the arrayed waveguide grating uses silicon nitride as the waveguide material, and silicon dioxide as the cladding material.

Further, the first input waveguide, the array waveguide and the second output waveguide are all strip waveguides.

Further, the tapered structures of the first arrayed waveguide tapered port, the second arrayed waveguide tapered port, and the second output port are symmetrical tapered structures.

A second aspect provides a communication device configured with the arrayed waveguide grating whose input port is an asymmetric tapered structure as described in the first aspect.

Compared with the prior art, the beneficial effects achieved by the present invention are as follows: the input waveguide of the present invention inputs the light source into the free propagation area in the non-central area of the Rowland circle through the tapered structure of the input port; the tapered structure of the input port is an asymmetrical tapered structure , including a symmetrical trapezoidal structure connected to the input waveguide, a trapezoidal structure connecting the symmetrical trapezoidal structure and a free propagation area; the asymmetric tapered structure proposed by the present invention, by designing the tapered structure as an asymmetrical structure at the light source input port The shape realizes the adjustment of light field distribution in the far field of the light source input into the free propagation region from the edge waveguide, thereby improving the loss uniformity among the channels of the arrayed waveguide grating whose input port of the light source is at a non-center position. This method is simple and easy, only needs to rationally optimize the asymmetric structure, and can be processed by using the existing planar waveguide manufacturing process, and is suitable for arrayed waveguide gratings whose input light source ports are located at non-central points of the Rowland circle.

Description of drawings

FIG. 1 is a schematic structural diagram of an arrayed waveguide grating with an input port of an asymmetric tapered structure provided by an embodiment of the present invention;

Fig. 2 is a structural schematic diagram of the input port of the asymmetric tapered structure in Fig. 1;

Fig. 3 is the deformation structure one of Fig. 2;

Fig. 4 is the deformation structure two of Fig. 2;

Fig. 5 is the deformation structure three of Fig. 2;

Fig. 6 is a comparison diagram of the spectral response of arrayed waveguide gratings with different shapes of incident ports;

In the figure: 1. The first input waveguide; 2. The first output waveguide; 3. The tapered structure of the first input port; 4. The tapered structure of the first output port; 5. The first free propagation area; 6. The first array 7. Arrayed waveguide; 8. Second arrayed waveguide tapered port; 9. Second free propagation area; 10. Tapered structure of the second output port; 11. Tapered structure of the second input port; 12. The second output waveguide; 13, the second input waveguide; 14, the trapezoidal structure; 141, the rectangle; 142, the right triangle away from the center of the Rowland circle; 143, the right triangle close to the center of the Rowland circle; 144, the first right trapezoid; 145. A second right-angled trapezoid; 146. A quadrilateral with one right angle; 15. A symmetrical trapezoidal structure.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings. The following examples are only used to illustrate the technical solution of the present invention more clearly, but not to limit the protection scope of the present invention.

Embodiment one:

As shown in Figure 1, an arrayed waveguide grating whose input port is an asymmetric tapered structure includes: a first input waveguide 1, a second input waveguide 13, a first free propagation region 5, an arrayed waveguide 7, a second free propagation Area 9, the first output waveguide 2, the second output waveguide 12; the second output waveguide 12 is connected with the second free propagation area 9 through the second output port tapered structure 10; the first output waveguide 2 is connected through the first output port tapered The structure 4 is connected to the first free propagation area 5; the second free propagation area 9 is connected to the arrayed waveguide 7 through the second arrayed waveguide tapered port 8; the arrayed waveguide 7 is connected to the first free propagation area through the first arrayed waveguide tapered port 6 5 connection; the first input waveguide 1 enters the light source into the first free propagation area 5 through the first input port tapered structure 3 in the non-central area of the Rowland circle; the second input waveguide 13 passes through the second input port tapered structure 11 in the Rowland circle The non-central area of the circle feeds the light source into the second free propagation area 9 .

The first input port tapered structure 3 and the second input port tapered structure 11 have the same structure, both of which are asymmetrical tapered structures. As shown in Figures 1 and 2, the first input port tapered structure 3 is taken as an example for illustration. The first input port tapered structure 3 includes a symmetrical trapezoidal structure 15 connected to the first input waveguide 1, a symmetrical trapezoidal structure 15 connected Trapezoidal structure 14 with first free propagation zone 5 . The trapezoidal structure 14 is deconstructed into a rectangle 141 connected with the symmetrical trapezoidal structure 15 and right-angled triangles on both sides of the rectangle, wherein the side length of the side of the right-angled triangle 142 away from the center of the Rowland circle on the first free propagation area 5 is greater than The side length of the side of the right triangle 143 close to the center of the Rowland circle on the first free propagation area 5 .

In this embodiment, the input port of the light source is located at the edge waveguide, and the port is an arrayed waveguide grating with an asymmetric tapered structure. The arrayed waveguide grating may be a single-input multi-output arrayed waveguide grating, a multi-input multi-output arrayed waveguide grating, a reflective arrayed waveguide grating, and the like.

The arrayed waveguide grating uses silicon nitride as the waveguide material (refractive index near 535nm wavelength is 2.036) with a thickness of 180nm, silicon dioxide as the cladding material (refractive index is 1.44) with a thickness of 3μm, and the working band of the arrayed waveguide is: 525-540nm The range, the arrayed waveguide grating is 1×8, and the wavelength interval between the output channels is 1.8nm.

Both the input/output waveguide and the array waveguide are strip waveguides. The junction of the waveguide and the free transmission area is connected with a tapered waveguide. The tapered structure of the output waveguide and the arrayed waveguide is a symmetrical tapered waveguide whose width gradually expands linearly, while the input port is an asymmetric tapered structure.

As shown in FIG. 1 and FIG. 3 , the side and the opposite side of the trapezoidal structure 14 on the free transmission area may not be parallel. The trapezoidal structure 14 is deconstructed into a first right-angled trapezoid 144 connected with the symmetrical trapezoidal structure 15 and right-angled triangles positioned on both sides of the first right-angled trapezoidal 144, wherein the hypotenuse of the first right-angled trapezoidal 144 is connected with the symmetrical trapezoidal structure 15, The side length of the side of the right triangle 142 away from the center of the Rowland circle on the first free propagation area 5 is longer than the side length of the side of the right triangle 143 near the center of the Rowland circle on the first free propagation area 5 . Therefore, the opening of the asymmetric tapered structure in the direction away from the center of the Rowland circle is asymmetrically enlarged, and is larger than the opening in the direction close to the center of the Rowland circle.

As shown in FIG. 1 and FIG. 4 , the trapezoidal structure 14 is cut off on one side close to the center of the Rowland circle, and the cut-off part has the shape of a right triangle close to the center of the Rowland circle. The trapezoidal structure 14 is deconstructed into a second right-angled trapezoid 145 connected with the symmetrical trapezoidal structure 15 and a right-angled triangle on one side of the second right-angled trapezoidal 145, wherein the long right-angled side of the second right-angled trapezoid 145 is connected with the symmetrical trapezoidal structure 15 , the right triangle is a right triangle 142 away from the center of the Rowland circle, and a right triangle 143 close to the center of the Rowland circle is cut off.

As shown in FIG. 1 and FIG. 5 , the trapezoidal structure 14 synthesizes the structures in FIG. 3 and FIG. 4 . The trapezium structure 14 is deconstructed into a quadrilateral 146 connected with the symmetrical trapezoidal structure 15 with a right angle and a right triangle on one side of the quadrilateral, wherein the right triangle is a right triangle 142 away from the center of the Rowland circle, and a right angle near the center of the Rowland circle Triangle 143 is cut away.

As shown in Figure 4, the total length of the side length of the side of the asymmetric tapered structure on the free transmission region is 3 μm; The vertical distance is 10 μm; the side length of the long right-angled side of the second right-angled trapezoid 145 is set to 1.55 μm, and the side length of the side connecting the right-angled triangle 142 far away from the center of the Rowland circle and the first free propagation area 5 is 1.65 μm, close to the Rowland circle The length of the side connecting the central right-angled triangle 143 and the first free propagation region 5 is 0.2 μm, that is, the side length of the side of the asymmetric tapered structure on the free transmission region is: 1.65 μm + 1.55 μm −0.2 μm = 3 μm . The length of the side shared by the symmetrical trapezoidal structure 15 and the trapezoidal structure 14 is 1.55 μm, the height of the symmetrical trapezoidal structure 15 is 12 μm, and the side length of the symmetrical trapezoidal structure 15 connected to the first input waveguide 1 is the same as the width of the first input waveguide, The same is 0.5 μm. The tapered structure of the ports of other output channels is a traditional tapered (symmetrical trapezoidal) structure, the side length of the side on the free transmission area is 1.2 μm, and the side length of the side connected to the waveguide is 0.5 μm. The total length is 12 μm.

As shown in Fig. 6, the spectral response of the arrayed waveguide grating (dotted line) with the traditional tapered structure at the light source incident interface and the spectral response (solid line) of the asymmetric tapered structure arrayed waveguide grating at the light source incident interface are respectively contrast. The input port structure (the first input port tapered structure 3 and the second input port tapered structure 11) of the arrayed waveguide grating whose incident end of the light source is a traditional tapered structure is a symmetrical trapezoidal structure; the output port tapered structure (No. The first output port conical structure 4 and the second output port conical structure 10) are a symmetrical trapezoidal structure. Wherein, the incident interface of the light source is an asymmetric tapered arrayed waveguide grating. The incident interface of the arrayed waveguide grating adopts the asymmetric tapered structure shown in Fig. 4, and its structural parameters are the parameters described in the structure shown in Fig. Except for the different parameters of the incident end interface, all other structural parameters of the two arrayed waveguide gratings (the light source incident end interface is an arrayed waveguide grating with a traditional tapered structure, and the light source incident end interface is an asymmetric tapered structure arrayed waveguide grating) are the same. It can be seen from Figure 6 that the spectral output response of arrayed waveguide gratings with symmetrically tapered incident ports is quite different. In the 0.525 to 0.54 μm band, the display shows a gradual decrease in intensity response from short wavelengths to long wavelengths. The relative intensity difference between the maximum output and the minimum output in the channel is 0.17, while the spectral output of the arrayed waveguide grating with an asymmetric tapered input port is relatively uniform. In the 0.525 to 0.54 μm band, the relative intensity difference between the maximum output and the minimum output in the channel is only 0.04.

The asymmetric tapered structure proposed by the present invention realizes the adjustment of the light field distribution at the far field of the light source input into the free propagation area from the edge waveguide by designing the tapered structure as an asymmetrical structural shape at the light source input port, thus The loss uniformity among channels of the arrayed waveguide grating in which the input port of the light source is not at the center is improved. This method is simple and easy, only needs to rationally optimize the asymmetric structure, and can be processed by using the existing planar waveguide manufacturing process, and is suitable for arrayed waveguide gratings whose input light source ports are located at non-central points of the Rowland circle.

The invention has a simple structure, no additional devices, and is easy to design and process; the integration degree of the devices will not be reduced; for the arrayed waveguide grating whose input light source is not at the center of the Rowland circle, the channel loss uniformity can be effectively improved through this design.

Embodiment two:

Based on the arrayed waveguide grating whose input port is an asymmetric tapered structure as described in Embodiment 1, this embodiment provides a communication device configured with the input port described in Embodiment 1 having an asymmetric tapered structure. Arrayed Waveguide Grating.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, some improvements and modifications can also be made. It should also be regarded as the protection scope of the present invention.

Claims (10)

1. An arrayed waveguide grating whose input port is an asymmetric tapered structure, is characterized in that, comprising: sequentially connected first input waveguide (1), first free propagation region (5), array waveguide (7), second free propagation region (9) and second output waveguide (12); The second output waveguide (12) is connected to the second free propagation area (9) through a second output port tapered structure (10); The second free propagation region (9) is connected to the arrayed waveguide (7) through a second arrayed waveguide tapered port (8); The arrayed waveguide (7) is connected to the first free propagation region (5) through a first arrayed waveguide tapered port (6); The first input waveguide (1) inputs the light source into the first free propagation area (5) in the non-central area of the Rowland circle through the first input port tapered structure (3); The first input port tapered structure (3) is an asymmetric tapered structure, including a symmetrical trapezoidal structure connected to the first input waveguide (1), and a Trapezoidal structure (14). 2. The arrayed waveguide grating whose input port is an asymmetric tapered structure according to claim 1, wherein the trapezoidal structure (14) is decomposed into a rectangle (141) connected with a symmetrical trapezoidal structure (15). ) and right-angled triangles located on both sides of the rectangle (141), wherein the side length of the right-angled triangle (142) away from the center of the Rowland circle on the first free propagation area (5) is larger than that of the right-angled triangle (143 ) is the side length of the side on the first free propagation area (5). 3. The arrayed waveguide grating whose input port is an asymmetric tapered structure according to claim 1, wherein the trapezoidal structure (14) is decomposed into a first right angle connected to the symmetrical trapezoidal structure (15) Trapezoid (144) and right triangles located on both sides of the first right trapezoid (144), wherein the hypotenuse of the first right trapezoid (144) is connected to the symmetrical trapezoidal structure (15), and the right triangle (142) away from the center of the Rowland circle The side length of the side on the first free propagation area (5) is greater than the side length of the side of the right triangle (143) near the center of the Rowland circle on the first free propagation area (5). 4. The arrayed waveguide grating whose input port is an asymmetric tapered structure according to claim 1, characterized in that, the trapezoidal structure (14) is decomposed into a second right angle connected to the symmetrical trapezoidal structure (15) Trapezoid (145) and a right triangle located on one side of the second right trapezoid (145), wherein the long right side of the second right trapezoid (145) is connected to the symmetrical trapezoid structure (15), and the right triangle is a right angle away from the center of the Rowland circle Triangle (142). 5. The arrayed waveguide grating whose input port is an asymmetric tapered structure according to claim 1, wherein the trapezoidal structure (14) is decomposed into a right-angled trapezoidal structure (15) connected with A quadrilateral (146) and a right triangle on one side of the quadrilateral (146) with one right angle, wherein the right triangle is a right triangle (142) away from the center of the Rowland circle. 6. The input port according to claim 1 is an arrayed waveguide grating with an asymmetric tapered structure, wherein the arrayed waveguide grating is a single-port input multi-port arrayed waveguide grating, a multi-port input multi-port output arrayed waveguide grating , reflective arrayed waveguide grating or symmetrical arrayed waveguide grating. 7 . The arrayed waveguide grating whose input port is an asymmetric tapered structure according to claim 1 , wherein the arrayed waveguide grating uses silicon nitride as a waveguide material, and silicon dioxide as a cladding material. 8. The arrayed waveguide grating whose input port is an asymmetric tapered structure according to claim 1, characterized in that the first input waveguide (1), the arrayed waveguide (7) and the second output waveguide (12) are strips shaped waveguide. 9. The arrayed waveguide grating whose input port is an asymmetric tapered structure according to claim 1, characterized in that the first arrayed waveguide tapered port (6), the second arrayed waveguide tapered port (8), the second The output port tapered structure (10) is a symmetrical tapered structure. 10. A communication device, characterized in that the communication device is configured with the arrayed waveguide grating whose input port is an asymmetric tapered structure according to any one of claims 1 to 9.

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