Optical receiving engine based on planar waveguide chip

Abstract

This application relates to an optical receiving engine based on a planar waveguide chip, belonging to the field of optical communication technology. The optical receiving engine based on a planar waveguide chip includes: an arrayed waveguide chip for receiving optical signals emitted from an optical fiber, wherein the output waveguide of the arrayed waveguide chip has a multimode waveguide structure, and light rays are output after passing through the output waveguide after being incident on the arrayed waveguide chip; different wavelengths of light correspond to different mode field distributions of the output waveguide; a detector coupled to the arrayed waveguide chip, wherein the photosensitive area of ​​the detector is determined based on the mode field distribution range of the output waveguide; and an amplifier connected to the detector. This can solve the problem of low coupling efficiency between existing arrayed waveguide chips and detectors. By optimizing the photosensitive area of ​​the detector, the photosensitive area can be matched with the light spot mode field of the waveguide chip, thereby improving the coupling efficiency.

Description

Technical Field

[0001] The present application relates to an optical receiving engine based on a planar waveguide chip, belonging to the technical field of optical communications. Background Art

[0002] With the advent of the 5G era, the demand for data transmission has exploded, and optical fiber communication technology has always attracted attention due to its high bandwidth characteristics. Optical transceiver devices are an important part of the overall optical communication link, and their function is to realize the conversion of optical and electrical signals.

[0003] Since the wavelength division multiplexing structure can effectively utilize the high bandwidth characteristics of optical fiber, wavelength division multiplexing devices can be used to couple multiple optical signals of different wavelengths into a single optical fiber. In order to realize the coupling and decoupling functions of light in optical fibers with wavelength division multiplexing structures, arrayed waveguide chips are usually used to realize the splitting processing of light in optical fibers.

[0004] At the optical receiving end, the array waveguide chip needs to have a wavelength-insensitive characteristic, that is, a flat-top transmission spectrum. In a typical way, the flat-top transmission spectrum is achieved by making the output waveguide of the array waveguide chip into a multimode waveguide structure. At this time, when the wavelength changes, the mode field distribution of the output waveguide of the array waveguide chip changes accordingly.

[0005] However, the array waveguide chip with a multi-mode waveguide structure cannot maintain the single mode field characteristics at the output end, which makes the coupling between the array waveguide chip and the detector difficult and the coupling efficiency is low. Summary of the invention

[0006] The present application provides an optical receiving engine based on a planar waveguide chip, which can solve the problem of low coupling efficiency between existing array waveguide chips and detectors. The present application provides the following technical solutions:

[0007] The optical receiving engine based on the planar waveguide chip includes:

[0008] An array waveguide chip for receiving optical signals emitted by an optical fiber, wherein the output waveguide of the array waveguide chip has a multimode waveguide structure, and light is incident on the array waveguide chip and output through the output waveguide; light with different wavelengths corresponds to different mode field distributions of the output waveguide;

[0009] a detector coupled to the array waveguide chip, wherein the photosensitive area of ​​the detector is determined based on the mode field distribution range of the output waveguide; and

[0010] An amplifier is connected to the detector.

[0011] Optionally, the normal direction of the light emitting surface of the arrayed waveguide chip points to the photosensitive area of ​​the detector.

[0012] Optionally, the arrayed waveguide chip is formed with a total reflection surface, which is used to totally reflect the light transmitted in the arrayed waveguide chip to the upper surface of the arrayed waveguide chip for emission; the center of the photosensitive area of ​​the detector coincides with the center of the output light field of the upper surface.

[0013] Optionally, the arrayed waveguide chip is supported by a support member so that a preset distance is between the detector and an area of ​​the upper surface of the arrayed waveguide chip for emitting light.

[0014] Optionally, the photosensitive area of ​​the detector includes the mode field distribution range of the output waveguide, and the size of the photosensitive area is less than or equal to a size threshold.

[0015] Optionally, the shape of the mode field distribution range is a rectangle, and accordingly, the photosensitive area of ​​the detector is a rectangle, and the ratio of the width to the height of the rectangle of the photosensitive area is equal to the ratio of the width to the height of the rectangle of the mode field distribution range.

[0016] Optionally, the shape of the mode field distribution range is elliptical, and accordingly, the photosensitive area of ​​the detector is elliptical, and the ratio of the major axis to the minor axis of the ellipse of the photosensitive area is equal to the ratio of the major axis to the minor axis of the ellipse of the mode field distribution range.

[0017] Optionally, the detector is connected to the amplifier by gold wire bonding.

[0018] Optionally, the arrayed waveguide chip includes a core layer and a cladding wrapped around the core layer, the ratio of the width to the height of the core layer is in the range of [3, 5]; the difference between the refractive index of the core layer and the refractive index of the cladding is in the range of [0.75%, 2.5%].

[0019] Optionally, the amplifier is a transimpedance amplifier.

[0020] The beneficial effects of the present application are as follows: by setting an array waveguide chip for receiving optical signals emitted by an optical fiber, the output waveguide of the array waveguide chip has a multi-mode waveguide structure, and light is incident on the array waveguide chip and output through the output waveguide; light with different wavelengths corresponds to different mode field distributions of the output waveguide; a detector coupled to the array waveguide chip, the photosensitive area of ​​the detector is determined based on the mode field distribution range of the output waveguide; and an amplifier connected to the detector; the problem of low coupling efficiency between the existing array waveguide chip and the detector can be solved; by optimizing the photosensitive area of ​​the detector, the photosensitive area can be matched with the light spot mode field of the waveguide chip, thereby improving the coupling efficiency.

[0021] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present application in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 and Figure 2 is a schematic diagram of the structure of an optical receiving engine based on a planar waveguide chip provided by an embodiment of the present application;

[0023] Figure 3 is a cross-sectional schematic diagram of an arrayed waveguide chip provided by an embodiment of the present application;

[0024] Figure 4 is a schematic diagram of a photosensitive area of ​​a detector provided by an embodiment of the present application;

[0025] Figure 5 It is a schematic diagram of a photosensitive area of ​​a detector provided in another embodiment of the present application. DETAILED DESCRIPTION

[0026] The specific implementation methods of the present application are further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application but are not intended to limit the scope of the present application.

[0027] Figure 1 and Figure 2 : is a schematic diagram of the structure of an optical receiving engine based on a planar waveguide chip provided by an embodiment of the present application. As shown in the figure, the optical receiving engine at least includes:

[0028] An array waveguide chip 1 for receiving an optical signal emitted by an optical fiber, wherein the output waveguide of the array waveguide chip 1 has a multimode waveguide structure, and light is incident on the array waveguide chip 1 and output through the output waveguide; light with different wavelengths corresponds to different mode field distributions of the output waveguide;

[0029] A detector 2 coupled to the array waveguide chip 1, wherein the photosensitive area of ​​the detector 2 is determined based on the mode field distribution range of the output waveguide; and

[0030] An amplifier 3 is connected to the detector 2.

[0031] Optionally, the photosensitive area of ​​the detector 2 is determined based on a variation range of a peak position in a mode field distribution of the output waveguide.

[0032] refer to Figure 3The cross-sectional view of the arrayed waveguide chip 1 shown in FIG. 1 includes a core layer 11 and a cladding layer 12 wrapped around the core layer 11. Optionally, in order to ensure the optical transmission quality and transmission efficiency of the arrayed waveguide chip 1, the core layer 11 is rectangular, and the ratio of the width to the height of the rectangle is in the range of [3, 5]; the difference between the refractive index of the core layer 11 and the refractive index of the cladding layer 12 is in the range of [0.75%, 2.5%].

[0033] Optionally, the array waveguide chip 1 and the detector 2 are coupled in the following ways, but not limited to:

[0034] The first (reference Figure 1 ): The normal direction of the light-emitting surface of the arrayed waveguide chip 1 points to the photosensitive area of ​​the detector 2. Optionally, the detector 2 is directly fixed on the light-emitting surface of the arrayed waveguide chip 1; or, air is spaced between the detector 2 and the light-emitting surface of the arrayed waveguide chip 1.

[0035] The second (reference Figure 2 ): The array waveguide chip 1 is formed with a total reflection surface 13, which is used to fully reflect the light transmitted in the array waveguide chip 1 to the upper surface 14 of the array waveguide chip 1 for emission; the center of the photosensitive area of ​​the detector 2 coincides with the center of the output light field of the upper surface 14. Figure 2 The optical signal inside the array waveguide chip 1 (indicated by the dotted arrow) passes through the total reflection surface 13 of the array waveguide chip 1, emerges from the upper surface 14, and after being refracted at the interface between the array waveguide chip 1 and the air layer, points to the center of the photosensitive area of ​​the detector 2.

[0036] Optionally, since the total reflection surface 13 has edges and corners, in order to prevent the detector 2 from being directly mounted on the upper surface 14 and possibly coming into contact with the total reflection surface 13 and causing damage, in this embodiment, the array waveguide chip 1 is supported by a support member 4 so that a preset distance is separated between the detector 2 and the area on the upper surface 14 of the array waveguide chip used for emitting light.

[0037] The total reflection surface 13 may be formed by polishing the end surface of the arrayed waveguide chip 1; or, may be formed by a reflector disposed on the end surface of the arrayed waveguide chip 1. This embodiment does not limit the arrangement of the total reflection surface 13.

[0038] Optionally, the detector 2 and the amplifier 3 may be connected by gold wire bonding.

[0039] Optionally, the amplifier 3 may be a trans-impedance amplifier (TIA), or of course, may be other types of amplifiers, which is not limited in this embodiment.

[0040] In this embodiment, the photosensitive area of ​​the detector 2 is determined based on the mode field distribution range of the output waveguide in the following manner: the photosensitive area of ​​the detector 2 includes the mode field distribution range, and the size of the photosensitive area is less than or equal to the size threshold.

[0041] Optionally, the photosensitive area of ​​the detector 2 is greater than or equal to the mode field distribution range of the output waveguide.

[0042] The size threshold is determined according to the maximum detection bandwidth of the detector 2. Since the maximum detection bandwidth of the detector 2 is fixed, and the larger the photosensitive area of ​​the detector 2, the smaller the corresponding bandwidth, therefore, in order to ensure the maximum detection bandwidth requirement of the detector 2 in this embodiment, the photosensitive area of ​​the detector 2 is less than or equal to the size threshold.

[0043] Optionally, refer to Figure 4 , the shape of the mode field distribution range of the output waveguide is a rectangle, and accordingly, the photosensitive area of ​​the detector is a rectangle, and the ratio of the width to the height of the rectangle of the photosensitive area is equal to the ratio of the width to the height of the rectangle of the mode field distribution range. For example: if the ratio of the width to the height of the rectangle of the mode field distribution range is 2:1, then the ratio of the width to the height of the rectangle of the photosensitive area is 2:1. At this time, the photosensitive area of ​​the detector 2 can detect the mode field distribution of the output waveguide corresponding to each wavelength.

[0044] Alternatively, refer to Figure 5 , the shape of the mode field distribution range is an ellipse, and accordingly, the photosensitive area of ​​the detector is an ellipse, and the ratio of the major axis to the minor axis of the ellipse of the photosensitive area is equal to the ratio of the major axis to the minor axis of the ellipse of the mode field distribution range. For example: if the ratio of the major axis to the minor axis of the ellipse of the mode field distribution range is 2:1, then the ratio of the major axis to the minor axis of the ellipse of the photosensitive area is also 2:1. At this time, the photosensitive area of ​​the detector 2 can detect the mode field distribution of the output waveguide corresponding to each wavelength.

[0045] In this embodiment, the size of the photosensitive area of ​​the detector 2 is determined based on the size of the mode field distribution range of the output waveguide. The size of the photosensitive area of ​​the detector 2 does not need to be fixed to a size threshold, which can not only ensure the detection accuracy, but also reduce the area of ​​the photosensitive area of ​​the detector 2 in some scenarios, thereby increasing the maximum detection bandwidth of the detector 2.

[0046] Of course, the optical receiving engine based on the planar waveguide chip provided in this embodiment may also have other components, such as: a substrate with electrical functions and mechanical support functions, etc., which are not listed one by one in this embodiment.

[0047] In summary, the optical receiving engine based on the planar waveguide chip provided in the present embodiment is provided with an array waveguide chip for receiving the optical signal emitted by the optical fiber, the output waveguide of the array waveguide chip has a multimode waveguide structure, and the light is incident on the array waveguide chip and then output through the output waveguide; the mode field distribution of the output waveguide corresponding to the light with different wavelengths is different; the detector coupled with the array waveguide chip, the photosensitive area of ​​the detector is determined based on the mode field distribution range of the output waveguide; and the amplifier connected to the detector; the problem of low coupling efficiency between the existing array waveguide chip and the detector can be solved; because by optimizing the photosensitive area of ​​the detector, the photosensitive area can be matched with the light spot mode field of the waveguide chip, thereby improving the coupling efficiency.

[0048] In addition, the photosensitive area of ​​the detector in this embodiment includes the mode field distribution range of the output waveguide, and the size of the photosensitive area is less than or equal to the size threshold, which can not only reduce the junction capacitance of the detector, but also enhance the matching degree with the mode field of the array waveguide chip and improve the coupling efficiency; increasing the coupling tolerance can achieve installation without precise alignment and reduce the difficulty of installation.

[0049] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0050] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. An optical receiving engine based on a planar waveguide chip, characterized in that: The optical receiving engine comprises: An array waveguide chip for receiving optical signals emitted by an optical fiber, wherein the output waveguide of the array waveguide chip has a multimode waveguide structure, and light is incident on the array waveguide chip and output through the output waveguide; light with different wavelengths corresponds to different mode field distributions of the output waveguide; a detector coupled to the array waveguide chip, wherein the photosensitive area of ​​the detector is determined based on the mode field distribution range of the output waveguide; and an amplifier connected to the detector; The detector is connected to the amplifier via gold wire bonding; The arrayed waveguide chip comprises a core layer and a cladding layer wrapped around the core layer, the ratio of the width to the height of the core layer is in the range of [3, 5]; the difference between the refractive index of the core layer and the refractive index of the cladding layer is in the range of [0.75%, 2.5%].

2. The optical receiving engine according to claim 1, characterized in that: The normal direction of the light emitting surface of the array waveguide chip points to the photosensitive area of ​​the detector.

3. The optical receiving engine according to claim 1, characterized in that: The array waveguide chip is formed with a total reflection surface, which is used to totally reflect the light transmitted in the array waveguide chip to the upper surface of the array waveguide chip for emission; the center of the photosensitive area of ​​the detector coincides with the center of the output light field of the upper surface.

4. The optical receiving engine according to claim 3, characterized in that: The array waveguide chip is supported by a support member so that a preset distance is provided between the detector and an area on the upper surface of the array waveguide chip for emitting light.

5. The optical receiving engine according to any one of claims 1 to 4, characterized in that: The photosensitive area of ​​the detector includes the mode field distribution range of the output waveguide, and the size of the photosensitive area is less than or equal to a size threshold.

6. The optical receiving engine according to claim 5, characterized in that: The shape of the mode field distribution range is a rectangle. Accordingly, the photosensitive area of ​​the detector is a rectangle, and the ratio of the width to the height of the rectangle of the photosensitive area is equal to the ratio of the width to the height of the rectangle of the mode field distribution range.

7. The optical receiving engine according to claim 5, characterized in that: The shape of the mode field distribution range is an ellipse. Accordingly, the photosensitive area of ​​the detector is an ellipse, and the ratio of the major axis to the minor axis of the ellipse of the photosensitive area is equal to the ratio of the major axis to the minor axis of the ellipse of the mode field distribution range.

8. The optical receiving engine according to any one of claims 1 to 4, characterized in that: The amplifier is a transimpedance amplifier.

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