Silicon photonic chip, optical engine, and coupling method

Abstract

The present invention relates to a silicon photonic chip, which has a first input waveguide and a second input waveguide on the same side, the spacing between the first input waveguide and the second input waveguide is 20μm, the first input waveguide divides part of the light into a first MPD, and the second input waveguide divides part of the light into a second MPD. An optical engine, a laser chip is coupled with the first input waveguide or the second input waveguide in the silicon photonic chip. A light engine coupling method, fixing the silicon photonic chip; a chip mounter mounts the laser chip, and sets the chip mounter so that the optical axis of the laser chip is aligned with the symmetry line of all mark points, determines the input waveguide close to the laser chip, and writes the MPD corresponding to the input waveguide close to the laser chip into a program. After writing, only the value of the corresponding MPD is read, and then coupling and fixing the laser chip are performed. The beneficial effect is: using an ordinary low-precision chip mounter to achieve the required high-precision mounting, reducing production costs.

Description

Technical Field

[0001] The present invention relates to the technical field of optical engines, and in particular to a silicon photonic chip, an optical engine, and a coupling method. Background Art

[0002] Traditional light engine structure such as Figure 1 As shown, it includes: a laser chip, a DR4 silicon photonic chip, a collimating lens, an optical isolator and a converging lens. The DR4 silicon photonic chip has an input waveguide and four output waveguides. The input waveguide is distributed at 0°, and the four output waveguides are distributed parallel to each other. The laser chip is coupled with the input waveguide in the DR4 silicon photonic chip. The laser chip is fixed on a ceramic heat sink. The laser chip and the input waveguide are coupled with a collimating lens, an optical isolator and a converging lens in sequence along the direction of light propagation. In order to couple the lens, the input waveguide will split the light to the MPD to monitor the optical power coupled to the input waveguide. Due to the large insertion loss of the silicon photonic chip, in order to ensure that sufficient optical power enters the MZM modulator, the light usually split to the MPD is about 2%, and the rest of the light is split into an input of a first 1×2 coupler, and the first 1×2 coupler has two outputs. Each is coupled with the input of a second 1×2 coupler, that is, the number of second 1×2 couplers is two, and each output of each second 1×2 coupler is coupled with an output waveguide through an MZM modulator, that is, other light is divided into four output waveguides in equal proportions, and the four output waveguides of the DR4 silicon photonic chip are coupled with the same multi-channel optical fiber array; due to the large insertion loss of the silicon photonic chip itself, high-power laser chips (above 70mW) are usually used, and the lens is required to have a higher coupling efficiency, so the laser chip and the input waveguide patch error in the DR4 silicon photonic chip is required to be within ±10μm. If it exceeds 10μm, the coupling efficiency will decrease, so a high-precision patch machine (patch error ±10μm) is required to patch the laser chip, and the high-precision patch machine is expensive, resulting in high production costs. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a silicon photonic chip, an optical engine, and a coupling method to overcome the deficiencies in the above-mentioned prior art.

[0004] The technical solution of the present invention to solve the above technical problems is as follows:

[0005] A silicon photonic chip has a first input waveguide and a second input waveguide distributed in parallel on the same side. The spacing between the first input waveguide port and the second input waveguide port is 20 μm. The first input waveguide distributes part of the light to a first MPD, and the rest of the light is distributed in equal proportions to four output waveguides. The second input waveguide distributes part of the light to a second MPD, and the rest of the light is distributed in equal proportions to four output waveguides. The outer sides of the first input waveguide and the outer sides of the second input waveguide each have at least two mark points, and all the mark points are symmetrically distributed about the symmetry line of the first input waveguide and the second input waveguide.

[0006] The beneficial effects of the present invention are:

[0007] Since the silicon photonic chip has a first input waveguide and a second input waveguide distributed in parallel on the same side, and the spacing between the first input waveguide port and the second input waveguide port is 20μm, when it is used in a light engine and coupled with a laser chip, the placement machine with an accuracy range of -20μm to 20μm can be set to align the target position of the laser chip optical axis patch with the symmetry line of all mark points. That is, with the help of the mark point, the target position of the laser chip optical axis patch can be better determined. At this time, theoretically, the target position of the laser chip optical axis patch is relative to the first input waveguide and the second input waveguide. The guide is pre-biased by 10μm, but due to the accuracy error of the placement machine, the laser chip can only be closer to one of the first input waveguide or the second input waveguide, and the actual distance to the closer input waveguide does not exceed 10μm, that is, the coupling efficiency requirement is met, thereby achieving the required high-precision placement regardless of whether it is an ordinary low-precision placement machine or a high-precision placement machine, so as to provide more selectivity. For example, a low-precision placement machine with an accuracy of ±20μm, a low-precision placement machine with an accuracy of ±15μm, and a high-precision placement machine with an accuracy of ±10μm are used, which is conducive to reducing production costs.

[0008] On the basis of the above technical solution, the present invention can also be improved as follows.

[0009] Furthermore, the outer side of the first input waveguide has two mark points, and the outer side of the second input waveguide has two mark points.

[0010] Further, the number of output waveguides is four.

[0011] Furthermore, the first input waveguide and the second input waveguide are respectively coupled to the two inputs of the 2×2 coupler, the two outputs of the 2×2 coupler are each coupled to the input of a 1×2 coupler, and each output of each 1×2 coupler is coupled to an output waveguide via an MZM modulator.

[0012] Based on the above technical solution, the present invention also provides an optical engine, including: a laser chip and a silicon photonic chip, the target position of the laser chip optical axis patch is aligned with the symmetry line of all mark points, and the laser chip is coupled to the first input waveguide or the second input waveguide in the silicon photonic chip.

[0013] A further beneficial effect of the above method is that an ordinary low-precision placement machine (placement accuracy of ±20μm) can also achieve high-precision placement effect (placement error of ±10μm), thereby reducing production costs.

[0014] Furthermore, a collimating lens, an optical isolator and a converging lens are sequentially coupled between the laser chip and the first input waveguide or the second input waveguide along the light propagation direction.

[0015] Furthermore, the multiple output waveguides of the silicon photonic chip are coupled to the same multi-channel optical fiber array.

[0016] Furthermore, the laser chip is fixed on a ceramic heat sink.

[0017] Based on the above technical solution, the present invention further provides a light engine coupling method for coupling the above light engine, comprising the following steps:

[0018] S1, fixed silicon photonic chip;

[0019] S2. Use a chip mounter with an accuracy range of -20μm to 20μm to mount the laser chip, and set the chip mounter to align the target position of the laser chip optical axis with the symmetry line of all mark points;

[0020] S3. Measure the distances between the optical axis of the laser chip and the first input waveguide and the second input waveguide respectively, determine the input waveguide closest to the laser chip, and write the MPD corresponding to the input waveguide closest to the laser chip into the program. After writing, only the corresponding MPD value is read, and then the laser chip is coupled and fixed.

[0021] A further beneficial effect of the above is that through this coupling method, both ordinary low-precision placement machines and high-precision placement machines can achieve the required high-precision placement (patch error ±10μm), providing more options, such as: using a low-precision placement machine with an accuracy of ±20μm, using a low-precision placement machine with an accuracy of ±15μm, and using a high-precision placement machine with an accuracy of ±10μm, which is conducive to reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural diagram of a light engine in the prior art;

[0023] Figure 2 This is a structural diagram of the silicon photonic chip in the present invention;

[0024] Figure 3 is a structural diagram of the light engine in the present invention;

[0025] Figure 4 This is the first coupling structure diagram of the laser chip and silicon photonic chip;

[0026] Figure 5 This is the second coupling structure diagram between the laser chip and the silicon photonic chip;

[0027] Figure 6 This is the third coupling structure diagram between the laser chip and the silicon photonic chip;

[0028] Figure 7 This is the fourth coupling structure diagram between the laser chip and the silicon photonic chip.

[0029] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0030] 1. Silicon photonic chip, 110. First input waveguide, 120. Second input waveguide, 130. First MPD, 140. Second MPD, 150. Output waveguide, 160. 2×2 coupler, 170. 1×2 coupler, 180. MZM modulator, 190. Mark point, 2. Laser chip, 3. Collimating lens, 4. Optical isolator, 5. Converging lens, 6. Multi-channel fiber array, 7. Ceramic heat sink. DETAILED DESCRIPTION

[0031] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0032] Example 1

[0033] like Figure 2As shown, a silicon photonic chip has a first input waveguide 110 and a second input waveguide 120 distributed in parallel on the same side, wherein the spacing between the ports of the first input waveguide 110 and the second input waveguide 120 is 20 μm; the first input waveguide 110 distributes part of the light to the first MPD 130, and the rest of the light is distributed in equal proportions to four output waveguides 150. For example, the first input waveguide 110 distributes approximately 2% of the light to the first MPD 130, and the rest of the light is distributed in equal proportions to the multiple output waveguides 150. Of course, this is only an illustrative example, and other ratios are not excluded in actual applications; the second input waveguide The first input waveguide 110 has at least two mark points 190 on its outer side, and the second input waveguide 120 has at least two mark points 190 on its outer side. All the mark points 190 are symmetrically distributed about the symmetry line between the first input waveguide 110 and the second input waveguide 120.

[0034] Since the silicon photonic chip 1 has a first input waveguide 110 and a second input waveguide 120 distributed in parallel on the same side, and the spacing between the first input waveguide 110 port and the second input waveguide 120 port is 20μm (the chip has a very high precision, generally at the nm level, and the precision <0.1μm can be ignored), when it is used in an optical engine and coupled with the laser chip 2, a patch machine with an accuracy range of -20μm to 20μm can be set to align the target patch position of the optical axis of the laser chip 2 with the symmetry line of all mark points 190, that is, with the help of the mark point 190, the target patch position of the optical axis of the laser chip 2 can be better determined. At this time, theoretically, the target patch position of the optical axis of the laser chip 2 is relative to the first input waveguide 110 and the second input waveguide 12 0 pre-bias 10μm, but due to the accuracy error of the placement machine, the laser chip can only be closer to one of the first input waveguide or the second input waveguide at this time, and the distance to the closer input waveguide does not exceed 10μm, that is, the coupling efficiency requirement is met, thereby achieving the required high-precision placement (placement error ±10μm) regardless of whether it is an ordinary low-precision placement machine or a high-precision placement machine, so as to provide more selectivity, such as: using a low-precision placement machine with an accuracy of ±20μm, a low-precision placement machine with an accuracy of ±15μm, and a high-precision placement machine with an accuracy of ±10μm, which is conducive to reducing production costs, while the existing technology cannot choose to use a low-precision placement machine with an accuracy of ±20μm, and cannot choose to use a low-precision placement machine with an accuracy of ±15μm.

[0035] Example 2

[0036] like Figure 2 As shown, this embodiment is a further improvement on the basis of embodiment 1, specifically as follows:

[0037] The outer side of the first input waveguide 110 has at least two mark points 190, at least two of which can refer to two, three, four, etc., and the figure shows that the outer side of the first input waveguide 110 has two mark points 190. Of course, this is just an exemplary example, and other numbers are not excluded in actual application; the outer side of the second input waveguide 120 has at least two of which can refer to two, three, four, etc., and the figure shows that the outer side of the second input waveguide 120 has two mark points 190. Of course, this is just an exemplary example, and other numbers are not excluded in actual application.

[0038] Example 3

[0039] like Figure 2 As shown, this embodiment is a further improvement on the basis of embodiment 1 or 2, specifically as follows:

[0040] There are four output waveguides 150, that is, the silicon photonic chip 1 has four output waveguides 150, and the first input waveguide 110 divides part of the light to the first MPD 130, and the remaining light is divided into four output waveguides 150 in equal proportions. The second input waveguide 120 divides part of the light to the second MPD 140, and the remaining light is divided into multiple output waveguides 150 in equal proportions. Therefore, the silicon photonic chip 1 can be regarded as a DR4 silicon photonic chip.

[0041] Furthermore, the first input waveguide 110 and the second input waveguide 120 are respectively coupled to the two inputs of the 2×2 coupler 160, and one of the two outputs of the 2×2 coupler 160 is coupled to the input of a 1×2 coupler 170, and the other output is coupled to the input of another 1×2 coupler 170. Thus, there are two 1×2 couplers 170, and each output of each 1×2 coupler 170 is coupled to the input of each MZM modulator 1. 80 is coupled to an output waveguide 150, that is, it has four MZM modulators 180, and the 2×2 coupler 160 and the 1×2 coupler 170 all split light in equal proportions, so that after the light output from the first input waveguide 110 is split into parts and directed to the first MPD 130, the remaining light can be split into the four output waveguides 150 in equal proportions, and after the light output from the second input waveguide 120 is split into parts and directed to the second MPD 140, the remaining light can also be split into the four output waveguides 150 in equal proportions.

[0042] Example 4

[0043] like Figure 3 As shown, an optical engine includes: a laser chip 2 and the silicon photonic chip 1 described in Example 1, 2 or 3, the target position of the optical axis patch of the laser chip 2 is aligned with the symmetry line of all mark points 190, and due to the accuracy error of the patch machine, when the laser chip 2 is patched by the patch machine, the laser chip 2 can only be closer to one of the first input waveguide 110 or the second input waveguide 120, and the distance to the closer input waveguide does not exceed 10μm. Ultimately, the laser chip 2 can only be coupled with the first input waveguide 110 or the second input waveguide 120 in the silicon photonic chip 1, that is, the coupling efficiency requirement is met, thereby achieving the required high-precision patching regardless of whether it is an ordinary low-precision patch machine or a high-precision patch machine, so as to provide more selectivity, for example: using a low-precision patch machine with an accuracy of ±20μm, using a low-precision patch machine with an accuracy of ±15μm, and using a high-precision patch machine with an accuracy of ±10μm, which is conducive to reducing production costs;

[0044] For example, if the patch accuracy is ±20 μm, and the target patch position of the optical axis of the laser chip 2 has been pre-biased by 10 μm relative to the first input waveguide 110 and the second input waveguide 120, the final patch error Z = 20 μm - 10 μm - laser patch error |X|. Since the value range of X is -20 μm to 20 μm, assuming that the deviation toward the first input waveguide 110 is negative and the deviation toward the second input waveguide 120 is positive, then:

[0045] When -10 μm<X<0, the optical axis patch position of the laser chip 2 is between the symmetry line and the first input waveguide 110, that is, it is closer to the first input waveguide 110 and the distance is less than 10 μm. Figure 4 As shown;

[0046] When the value of X is -10 μm, the optical axis patch position of the laser chip 2 is on the first input waveguide 110 , that is, the distance from the first input waveguide 110 is 0 μm;

[0047] When -10 μm<X≤-20 μm, the optical axis patch position of the laser chip 2 is outside the first input waveguide 110, that is, closer to the first input waveguide 110, and the distance is less than or equal to 10 μm. Figure 5 As shown;

[0048] When 0<X<10μm, the optical axis patch position of the laser chip 2 is between the symmetry line and the second input waveguide 120, that is, it is closer to the second input waveguide 120 and the distance is less than 10μm. For details, see Figure 6 As shown;

[0049] When the value of X is 10 μm, the optical axis patch position of the laser chip 2 is on the second input waveguide 120 , that is, the distance from the second input waveguide 120 is 0 μm;

[0050] When 10 μm<X≤20 μm, the optical axis patch position of the laser chip 2 is outside the second input waveguide 120, that is, closer to the second input waveguide 120, and the distance is less than or equal to 10 μm. Figure 7 As shown;

[0051] The same low-precision placement machine with an accuracy of ±15μm also has similar situations as above, which will not be described in detail here;

[0052] The reason why the value of X is 0 in the above values ​​is that it is almost impossible for the error to be 0 during the actual operation of the chip mounter. Therefore, the laser chip 2 can only be closer to one of the first input waveguide 110 or the second input waveguide 120.

[0053] Therefore, the absolute value of the patch error Z of the actual patch position of the optical axis of the laser chip 2 relative to the first input waveguide 110 or the second input waveguide 120 does not exceed 10μm. Therefore, an ordinary low-precision patch machine (patch accuracy of ±20μm) can also achieve the required high-precision patch (patch error of ±10μm), thereby reducing production costs. 100% measurement is performed after the laser chip 2 is completed.

[0054] Example 5

[0055] like Figure 3 As shown, this embodiment is a further improvement on the basis of embodiment 4, specifically as follows:

[0056] The collimating lens 3, the optical isolator 4, and the converging lens 5 are coupled in sequence between the laser chip 2 and the first input waveguide 110 or the second input waveguide 120 along the light propagation direction. That is, the emitted light of the laser chip 2 is coupled into the first input waveguide 110 or the second input waveguide 120 after passing through the collimating lens 3, the optical isolator 4, and the converging lens 5 in sequence.

[0057] Furthermore, the multiple output waveguides 150 of the silicon photonic chip are coupled to the same multi-channel optical fiber array 6 , and the multi-channel optical fiber array 6 can be a four-channel optical fiber array.

[0058] The laser chip 2 is preferably fixed on a ceramic heat sink 7 .

[0059] Example 6

[0060] like Figures 3 to 7 As shown, a light engine coupling method for coupling the light engine in Example 4 or 5 includes the following steps:

[0061] S1, fixed silicon photonic chip 1;

[0062] S2. Use a chip mounter with an accuracy range of -20μm to 20μm to mount the laser chip 2, and set the chip mounter so that the target position of the optical axis of the laser chip 2 is aligned with the symmetry line of all mark points 190;

[0063] S3, measuring the distances between the optical axis of the laser chip 2 and the first input waveguide 110 and the second input waveguide 120 respectively;

[0064] Assume that the distance between the laser chip 2 and the first input waveguide 110 is A, and the distance between the laser chip 2 and the second input waveguide 120 is B;

[0065] If A>B, the laser chip 2 is close to the second input waveguide 120. Then, the second MPD 140 corresponding to the second input waveguide 120 is written into program C. After writing, program C only reads the value of the second MPD 140, and then couples and fixes the laser chip 2.

[0066] If A<B, the laser chip 2 is close to the first input waveguide 110 , and the first MPD 130 corresponding to the first input waveguide 110 is written into program D. After writing program D, only the value of the first MPD 130 is read, and then the laser chip 2 is coupled and fixed.

[0067] Both ordinary low-precision placement machines and high-precision placement machines can achieve the required high-precision placement (patch error ±10μm) to provide more choices, such as: using a low-precision placement machine with an accuracy of ±20μm, a low-precision placement machine with an accuracy of ±15μm, and a high-precision placement machine with an accuracy of ±10μm, which is conducive to reducing production costs.

[0068] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A silicon photonic chip, characterized in that: The invention relates to a device for transmitting a first input waveguide (110) and a second input waveguide (120) which are distributed in parallel on the same side. The spacing between the first input waveguide (110) port and the second input waveguide (120) port is 20 μm. The first input waveguide (110) distributes part of the light to a first MPD (130), and the rest of the light is distributed in equal proportion to a plurality of output waveguides (150). The second input waveguide (120) distributes part of the light to a second MPD (140), and the rest of the light is distributed in equal proportion to a plurality of output waveguides (150). The outer side of the first input waveguide (110) and the outer side of the second input waveguide (120) each have at least two mark points (190), and all the mark points (190) are symmetrically distributed about the symmetry line of the first input waveguide (110) and the second input waveguide (120).

2. The silicon photonic chip according to claim 1, wherein: The outer side of the first input waveguide (110) has two mark points (190), and the outer side of the second input waveguide (120) has two mark points (190).

3. A silicon photonic chip according to claim 1 or 2, characterized in that: The number of the output waveguides (150) is four.

4. The silicon photonic chip according to claim 3, wherein: The first input waveguide (110) and the second input waveguide (120) are respectively coupled to two inputs of a 2×2 coupler (160); the two outputs of the 2×2 coupler (160) are each coupled to an input of a 1×2 coupler (170); and each output of each 1×2 coupler (170) is coupled to an output waveguide (150) via an MZM modulator (180).

5. A light engine, characterized in that: include: A laser chip (2) and a silicon photonic chip (1) as claimed in any one of claims 1 to 4, wherein the optical axis patch target position of the laser chip (2) is aligned with the symmetry line of all mark points (190), and the laser chip (2) is coupled to the first input waveguide (110) or the second input waveguide (120) in the silicon photonic chip (1).

6. The light engine according to claim 5, characterized in that: The laser chip (2) and the first input waveguide (110) or the second input waveguide (120) are sequentially coupled to a collimating lens (3), an optical isolator (4), and a converging lens (5) along the light propagation direction.

7. The light engine according to claim 5, characterized in that: The multiple output waveguides (150) of the silicon photonic chip are coupled to the same multi-channel optical fiber array (6).

8. The light engine according to claim 5, characterized in that: The laser chip (2) is fixed on a ceramic heat sink (7).

9. A light engine coupling method, characterized in that: For coupling the light engine according to any one of claims 5 to 8, comprising the following steps: S1, fixed silicon photonic chip (1); S2, using a chip mounter with an accuracy range of -20 μm to 20 μm to mount the laser chip (2), and setting the chip mounter to align the target position of the optical axis of the laser chip (2) with the symmetry line of all the mark points (190); S3. Measure the distances between the optical axis of the laser chip (2) and the first input waveguide (110) and the second input waveguide (120) respectively, determine the input waveguide closest to the laser chip (2), and write the MPD corresponding to the input waveguide closest to the laser chip (2) into the program. After writing, only read the corresponding MPD value, and then couple and fix the laser chip (2).

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