Silicon optical chip, optical engine and coupling method

Abstract

The invention relates to a silicon optical chip which is provided with a first input waveguide and a second input waveguide on the same side, the distance between the first input waveguide and the second input waveguide is 20 microns, the first input waveguide is divided into parts of light to a first MPD, and the second input waveguide is divided into parts of light to a second MPD. The invention discloses an optical engine. A laser chip is coupled with a first input waveguide or a second input waveguide in a silicon optical chip. The optical engine coupling method comprises the following steps: fixing a silicon optical chip; the chip mounter carries out chip mounting on the laser chip, the chip mounter is set to enable the optical axis of the laser chip to be aligned with the symmetric line of all the mark points, the input waveguide close to the laser chip is determined, the MPD corresponding to the input waveguide close to the laser chip is written into a program, only the value of the corresponding MPD is read after writing, and then the laser chip is coupled and fixed. The beneficial effects of the invention are that a common low-precision chip mounter is used to achieve required high-precision chip mounting, and the production cost is reduced.

Description

Technical Field

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

[0002] The structure of a traditional optical engine is as Figure 1 shown, which includes: a laser chip, a DR4 silicon photonics chip, a collimating lens, an optical isolator, and a focusing lens. The DR4 silicon photonics chip has an input waveguide and four output waveguides. The input waveguide is distributed at 0°, and the four output waveguides are parallelly distributed obliquely to each other. The laser chip is coupled to the input waveguide in the DR4 silicon photonics chip. The laser chip is fixed on a ceramic heat sink. A collimating lens, an optical isolator, and a focusing lens are sequentially coupled between the laser chip and the input waveguide along the light propagation direction. In order to couple the lens, the input waveguide will split a part of the light to the MPD to monitor the optical power coupled to the input waveguide. Since the silicon photonics chip has a large insertion loss, in order to ensure sufficient optical power enters the MZM modulator, usually about 2% of the light is split to the MPD, and the other light is split into the input of a first 1×2 coupler. Each of the two outputs of the first 1×2 coupler is coupled to the input of a second 1×2 coupler, that is, the number of the second 1×2 couplers is two. Each output of each second 1×2 coupler is coupled to an output waveguide through an MZM modulator, that is, the other light is split into the four output waveguides in an equal ratio. The four output waveguides of the DR4 silicon photonics chip are coupled to the same multi-channel fiber array; since the silicon photonics chip itself has a large insertion loss, usually a high-power laser chip (above 70 mW) is used, and a lens with a high coupling efficiency is required. Therefore, the chip placement error between the laser chip and the input waveguide in the DR4 silicon photonics chip is required to be within ±10 μm. If it exceeds 10 μm, the coupling efficiency will decrease. Therefore, a high-precision chip placer (chip placement error ±10 μm) is required to place the laser chip, and the high-precision chip placer 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 photonics 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 problem is as follows: A silicon photonics chip has a first input waveguide and a second input waveguide distributed in parallel on the same side. The distance between the first input waveguide port and the second input waveguide port is 20 μm. Part of the light in the first input waveguide is split to the first MPD, and the other light is split to four output waveguides in a geometric progression. Part of the light in the second input waveguide is split to the second MPD, and the other light is split to four output waveguides in a geometric progression. There are at least two mark points on the outer sides of the first input waveguide and the second input waveguide, and all the mark points are symmetrically distributed with respect to the symmetry line of the first input waveguide and the second input waveguide.

[0005] The beneficial effects of the present invention are as follows: Since the silicon photonics chip has a first input waveguide and a second input waveguide distributed in parallel on the same side, and the distance between the first input waveguide port and the second input waveguide port is 20 μm, when it is applied to an optical engine and coupled with a laser chip, a mounter with an accuracy range of -20 μm to 20 μm can be used to align the optical axis of the laser chip to the target position of the symmetry line of all the mark points. That is, with the help of the mark points, the target position of the optical axis of the laser chip can be determined better. At this time, theoretically, the target position of the optical axis of the laser chip is pre-deviated by 10 μm relative to the first input waveguide and the second input waveguide. However, due to the accuracy error of the mounter, the laser chip will only be closer to one of the first input waveguide or the second input waveguide, and the actual distance from the closer input waveguide does not exceed 10 μm, that is, the coupling efficiency requirement is met. Furthermore, whether it is a common low-precision mounter or a high-precision mounter, the required high-precision chip mounting can be achieved, providing more choices. For example, a low-precision mounter with an accuracy of ±20 μm, a low-precision mounter with an accuracy of ±15 μm, and a high-precision mounter with an accuracy of ±10 μm can be used, which is beneficial to reducing production costs.

[0006] On the basis of the above technical solution, the present invention can be further improved as follows.

[0007] Further, there are two mark points on the outer side of the first input waveguide and two mark points on the outer side of the second input waveguide.

[0008] Further, the number of output waveguides is four.

[0009] Furthermore, the first input waveguide and the second input waveguide are respectively coupled to the two inputs of a 2×2 coupler. Each of the two outputs of the 2×2 coupler is coupled to the input of a 1×2 coupler. Each output of each 1×2 coupler is coupled to an output waveguide through an MZM modulator.

[0010] Based on the above technical solution, the present invention further provides an optical engine, including: a laser chip and a silicon photonics chip. The optical axis of the laser chip is aligned with the symmetry line of all mark points at the patch target position, and the laser chip is coupled to the first input waveguide or the second input waveguide in the silicon photonics chip.

[0011] The further beneficial effect of adopting the above is that it can enable an ordinary low-precision mounter (with a patch precision of ±20 μm) to also achieve a high-precision patching effect (a patching error of ±10 μm), thereby reducing production costs.

[0012] 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.

[0013] Furthermore, multiple output waveguides of the silicon photonics chip are coupled to the same multi-channel fiber array.

[0014] Furthermore, the laser chip is fixed on a ceramic heat sink.

[0015] Based on the above technical solution, the present invention further provides an optical engine coupling method for coupling the above optical engine, including the following steps: S1. Fix the silicon photonics chip; S2. Use a mounter with a precision range of -20 μm to 20 μm to patch the laser chip, and set the mounter to align the optical axis of the laser chip at the patch target position with the symmetry line of all mark points; 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 closer to the laser chip, write the MPD corresponding to the input waveguide closer to the laser chip into the program, and only read the value of the corresponding MPD after writing, and then perform coupling and fixing of the laser chip.

[0016] The further beneficial effect of adopting the above is that through this coupling method, whether it is an ordinary low-precision mounter or a high-precision mounter can achieve the required high-precision patching (patching error ±10 μm), providing more choices, such as: using a low-precision mounter with a precision of ±20 μm, using a low-precision mounter with a precision of ±15 μm, and using a high-precision mounter with a precision of ±10 μm, which is beneficial to reducing production costs. Description of the Drawings

[0017] Figure 1 It is a structural diagram of an optical engine in the prior art; Figure 2 It is a structural diagram of the silicon photonics chip in the present invention; Figure 3 It is a structural diagram of the optical engine in the present invention; Figure 4 It is the first coupling structure diagram of the laser chip and the silicon photonics chip; Figure 5 It is the second coupling structure diagram of the laser chip and the silicon photonics chip; Figure 6 It is the third coupling structure diagram of the laser chip and the silicon photonics chip; Figure 7 It is the fourth coupling structure diagram of the laser chip and the silicon photonics chip.

[0018] In the accompanying drawings, the list of components represented by each label is as follows: 1. Silicon photonics 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. Multichannel fiber array, 7. Ceramic heat sink. Specific embodiments

[0019] The principles and features of the present invention will be described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0020] Embodiment 1 As Figure 2 shown, a silicon photonics chip has a first input waveguide 110 and a second input waveguide 120 distributed in parallel on the same side. Among them, the distance between the ports of the first input waveguide 110 and the second input waveguide 120 is 20 μm; a part of the light from the first input waveguide 110 is split to the first MPD 130, and the other light is split to four output waveguides 150 in an equal ratio. For example, if the first input waveguide 110 splits about 2% of the light to the first MPD 130, then the other about 98% of the light is split to multiple output waveguides 150 in an equal ratio. Of course, this is only an exemplary example, and other ratios are not excluded in actual applications; a part of the light from the second input waveguide 120 is split to the second MPD 140, and the other light is split to multiple output waveguides 150 in an equal ratio. For example, if the second input waveguide 120 splits about 2% of the light to the second MPD 140, then the other about 98% of the light is split to multiple output waveguides 150 in an equal ratio. Of course, this is only an exemplary example, and other ratios are not excluded in actual applications; there are at least two mark points 190 outside the first input waveguide 110, and there are at least two mark points 190 outside the second input waveguide 120. All the mark points 190 are symmetrically distributed with respect to the symmetry line of the first input waveguide 110 and the second input waveguide 120.

[0021] Since the silicon photonic chip 1 has a first input waveguide 110 and a second input waveguide 120 that are parallelly distributed on the same side, and the distance between the port of the first input waveguide 110 and the port of the second input waveguide 120 is 20 μm (the accuracy of the chip is very high, generally at the nm level, and the accuracy < 0.1 μm can be ignored), when it is applied to an optical engine and coupled with the laser chip 2, a mounter with an accuracy range of -20 μm to 20 μm can be used to align the optical axis patch target position of the laser chip 2 with the symmetry line of all the mark points 190, that is, with the help of the mark points 190, the optical axis patch target position of the laser chip 2 can be better determined. At this time, theoretically, the optical axis patch target position of the laser chip 2 is pre-deviated by 10 μm relative to the first input waveguide 110 and the second input waveguide 120. However, due to the accuracy error of the mounter, at this time, the laser chip will only be closer to one of the first input waveguide or the second input waveguide, and the distance from the closer input waveguide does not exceed 10 μm, that is, the coupling efficiency requirement is met. Furthermore, it can be realized that whether it is a common low-precision mounter or a high-precision mounter, high-precision patching (patching error ±10 μm) can be achieved, providing more selectivity. For example, a low-precision mounter with an accuracy of ±20 μm, a low-precision mounter with an accuracy of ±15 μm, and a high-precision mounter with an accuracy of ±10 μm can be used, which is beneficial to reducing production costs. In the prior art, it is impossible to select a low-precision mounter with an accuracy of ±20 μm and a low-precision mounter with an accuracy of ±15 μm.

[0022] Embodiment 2 As Figure 2 shown, this embodiment is a further improvement based on Embodiment 1, specifically as follows: On the outer side of the first input waveguide 110, at least two of the at least two mark points 190 can refer to two, three, four, etc. As shown in the drawings: there are two mark points 190 on the outer side of the first input waveguide 110. Of course, this is only an exemplary example here, and other quantities are not excluded in the actual application process; on the outer side of the second input waveguide 120, at least two of the at least two mark points 190 can refer to two, three, four, etc. As shown in the drawings: there are two mark points 190 on the outer side of the second input waveguide 120. Of course, this is only an exemplary example here, and other quantities are not excluded in the actual application process.

[0023] Embodiment 3 As Figure 2 shown, this embodiment is a further improvement based on Embodiment 1 or 2, specifically as follows: The number of output waveguides 150 is four, that is, the silicon photonic chip 1 has four output waveguides 150. And a part of the light from the first input waveguide 110 is directed to the first MPD 130, and the other light is directed to the four output waveguides 150 in a geometric progression. A part of the light from the second input waveguide 120 is directed to the second MPD 140, and the other light is directed to the multiple output waveguides 150 in a geometric progression. Therefore, the silicon photonic chip 1 can be regarded as a DR4 silicon photonic chip.

[0024] Furthermore, the first input waveguide 110 and the second input waveguide 120 are respectively coupled to the two inputs of a 2×2 coupler 160. 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. Then there are two 1×2 couplers 170. Each output of each 1×2 coupler 170 is coupled to an output waveguide 150 through an MZM modulator 180, that is, there are four MZM modulators 180. The 2×2 coupler 160 and the 1×2 couplers 170 all split the light in equal proportion. Thus, after a part of the light output from the first input waveguide 110 is directed to the first MPD 130, the other light can be directed to the four output waveguides 150 in a geometric progression, and after a part of the light output from the second input waveguide 120 is directed to the second MPD 140, the other light can also be directed to the four output waveguides 150 in a geometric progression.

[0025] Embodiment 4 As Figure 3 shown, an optical engine includes: a laser chip 2 and the silicon photonic chip 1 described in Embodiment 1 or 2 or 3. The optical axis patch target position of the laser chip 2 is aligned with the symmetry line of all the mark points 190. Due to the accuracy error of the mounter, when the laser chip 2 is patched by the mounter, the laser chip 2 will only be closer to one of the first input waveguide 110 or the second input waveguide 120, and the distance from the closer input waveguide does not exceed 10 μm. Finally, the laser chip 2 can only be coupled to 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. Furthermore, it can be realized that both ordinary low-precision mounters and high-precision mounters can achieve the required high-precision patching, providing more selectivity. For example, a low-precision mounter with an accuracy of ±20 μm, a low-precision mounter with an accuracy of ±15 μm, and a high-precision mounter with an accuracy of ±10 μm are adopted, which is beneficial to reducing the production cost; For example, the chip mounting accuracy is ±20μm. Since the optical axis of the laser chip 2 is pre-offset by 10μm relative to the target position of the first input waveguide 110 and the second input waveguide 120, the final chip mounting error Z = 20μm - 10μm - the absolute value of the laser chip mounting error |X|. Since the value range of X is -20μm to 20μm, assuming that the deviation towards the first input waveguide 110 is negative and the deviation towards the second input waveguide 120 is positive, then: When -10μm < X < 0, the chip mounting position of the optical axis of the laser chip 2 is between the symmetry line and the first input waveguide 110, that is, closer to the first input waveguide 110 and the distance is less than 10μm. For details, please refer to Figure 4 shown; When X takes the value of -10μm, the chip mounting position of the optical axis of the laser chip 2 is on the first input waveguide 110, that is, the distance from the first input waveguide 110 is 0μm; When -10μm < X ≤ -20μm, the chip mounting position of the optical axis 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 10μm. For details, please refer to Figure 5 shown; When 0 < X < 10μm, the chip mounting position of the optical axis of the laser chip 2 is between the symmetry line and the second input waveguide 120, that is, closer to the second input waveguide 120 and the distance is less than 10μm. For details, please refer to Figure 6 shown; When X takes the value of 10μm, the chip mounting position of the optical axis of the laser chip 2 is on the second input waveguide 120, that is, the distance from the second input waveguide 120 is 0μm; When 10μm < X ≤ 20μm, the chip mounting position of the optical axis 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 10μm. For details, please refer to Figure 7 shown; Similarly, in the case of using a low-precision chip mounter with an accuracy of ±15μm, there are similar situations as above, which will not be elaborated here in detail; In the above values, the value of X = 0 does not exist. The reason is that in the actual working process of the chip mounter, it is almost impossible for the error to be 0. Therefore, the laser chip 2 can only be closer to one of the first input waveguide 110 or the second input waveguide 120 finally; Therefore, the absolute value of the chip mounting error Z of the actual chip mounting 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 at all. Therefore, it is possible to make an ordinary low-precision chip mounter (chip mounting accuracy of ±20μm) also achieve the required high-precision chip mounting (chip mounting error of ±10μm), thereby reducing the production cost. After the laser chip 2 is mounted, 100% measurement is carried out.

[0026] Example 5 As Figure 3 shown, this example is a further improvement based on Example 4, specifically as follows: A collimating lens 3, an optical isolator 4, and a focusing lens 5 are sequentially coupled along the light propagation direction between the laser chip 2 and the first input waveguide 110 or the second input waveguide 120, 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 focusing lens 5 in sequence.

[0027] Furthermore, multiple output waveguides 150 of the silicon photonics chip are coupled to the same multi-channel fiber array 6, and the multi-channel fiber array 6 can be a four-channel fiber array.

[0028] The laser chip 2 is preferably fixed on a ceramic heat sink 7.

[0029] Example 6 As Figures 3 to 7 shown, an optical engine coupling method for coupling an optical engine as in Example 4 or 5 includes the following steps: S1. Fix the silicon photonics chip 1; S2. Use a mounter with an accuracy range of -20 μm to 20 μm to mount the laser chip 2, and set the mounter to align the optical axis patch target position of the laser chip 2 with the symmetry line of all 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; 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; If A > B, then the laser chip 2 is closer to the second input waveguide 120. Then write the second MPD 140 corresponding to the second input waveguide 120 into program C. After writing, program C only reads the value of the second MPD 140, and then couple and fix the laser chip 2; If A < B, then the laser chip 2 is closer to the first input waveguide 110. Then write the first MPD 130 corresponding to the first input waveguide 110 into program D. After writing, program D only reads the value of the first MPD 130, and then couple and fix the laser chip 2.

[0030] Both ordinary low-precision chip mounters and high-precision chip mounters can achieve the required high-precision chip mounting (chip mounting error ±10μm), providing more choices. For example, a low-precision chip mounter with a precision of ±20μm, a low-precision chip mounter with a precision of ±15μm, and a high-precision chip mounter with a precision of ±10μm are used, which is beneficial to reducing production costs.

[0031] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A silicon photonics chip, characterized in that, It has a first input waveguide (110) and a second input waveguide (120) that are parallelly distributed on the same side. The distance between the ports of the first input waveguide (110) and the second input waveguide (120) is 20 μm. Part of the light in the first input waveguide (110) is split and directed to the first MPD (130), and the other light is split and directed to multiple output waveguides (150) in a geometric progression. Part of the light in the second input waveguide (120) is split and directed to the second MPD (140), and the other light is split and directed to multiple output waveguides (150) in a geometric progression. There are at least two mark points (190) on the outer sides of both the first input waveguide (110) and the second input waveguide (120), and all the mark points (190) are symmetrically distributed with respect to the symmetry line of the first input waveguide (110) and the second input waveguide (120).

2. The silicon photonic chip according to claim 1, characterized in that There are two mark points (190) on the outer side of the first input waveguide (110), and there are two mark points (190) on the outer side of the second input waveguide (120).

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

4. A 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). Two outputs of the 2×2 coupler (160) are respectively coupled to the inputs of a 1×2 coupler (170). Each output of each 1×2 coupler (170) is coupled to an output waveguide (150) via an MZM modulator (180).

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

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

7. A light engine according to claim 5, characterized in that Multiple output waveguides (150) of the silicon photonics chip are coupled to the same multi-channel fiber array (6).

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

9. A method for coupling an optical engine, characterized in that, For coupling the optical engine as described in any one of claims 5 to 8, comprising the following steps: S1. Fix the silicon photonics chip (1); S2. Use a chip mounter with an accuracy range of -20 μm to 20 μm to patch the laser chip (2), and set the chip mounter to align the optical axis patch target position 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 closer to the laser chip (2), write the MPD corresponding to the input waveguide closer to the laser chip (2) into the program. After writing, only read the value of the corresponding MPD, and then perform coupling to fix the laser chip (2).

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