Double-lens coupling method and silicon light engine
By employing a fixed-distance and limited-direction movement method during the dual-lens coupling process, combined with image recognition and UV adhesive fixation, the time-consuming problem in existing technologies is solved, achieving efficient maximization of photocurrent and simplified coupling steps, thus improving product performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-02
- Publication Date
- 2026-04-10
AI Technical Summary
In existing technologies, the dual-lens coupling process is too time-consuming, the excessive number of movement directions leads to an increase in the number of coupling operations, and the stepping accuracy affects efficiency, making it difficult to quickly and efficiently maximize photocurrent.
Initial alignment is achieved by using a collimating lens at a fixed distance of 0.3mm ± 0.03mm from the laser chip and a converging lens at a fixed distance of 0.765mm ± 0.03mm from the silicon photonic chip or thin-film lithium niobate modulator chip. Subsequently, the collimating lens and converging lens are moved in four directions, and finally the collimating lens is adjusted in six directions to maximize the photocurrent value. This is combined with image recognition and UV adhesive fixation.
It shortens the coupling time, improves coupling efficiency, ensures that the photocurrent value of the final product reaches the maximum, simplifies the coupling steps, and improves product performance.
Smart Images
Figure CN121832011A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of light engines, in particular to a double-lens coupling method and a silicon light engine. BACKGROUND
[0002] A patent with application number 2022112841977 discloses a double-lens coupling packaging method of a laser and a modulator chip, which specifically comprises the following steps: placing and packaging the laser, isolator, and modulator chip from front to back; placing the collimating lens between the laser and the isolator, and making the defocused collimating lens focus the transmitted light to the light inlet of the modulator chip; fine-tuning the position of the collimating lens to make the photocurrent read by the photodetector integrated on the modulator chip maximum; translating the collimating lens along the optical axis to the laser direction by offset, wherein the offset is the translation distance that can make the transmitted light of the collimating lens convert from focused light to parallel light obtained by simulation software; solidifying the collimating lens at the current position; placing the focusing lens between the isolator and the modulator chip, fine-tuning the position of the focusing lens to make the photocurrent read by the photodetector integrated on the modulator chip maximum; and solidifying the focusing lens at the current position. In this scheme, when coupling the collimating lens, the collimating lens needs to be moved in the up, down, left, right, front, and back directions to make the photocurrent read by the photodetector integrated on the modulator chip maximum, and when coupling the focusing lens, the focusing lens also needs to be moved in the up, down, left, right, front, and back directions to make the photocurrent read by the photodetector integrated on the modulator chip maximum again. For example: moving the collimating lens forward, the photocurrent value read by the photodetector integrated on the modulator chip is recorded as M1, then continue to move the collimating lens forward, the photocurrent value is recorded as M2, if M2>M1, it means that the collimating lens needs to be moved forward, continue to move forward, the photocurrent value is recorded as M3, if M3>M2, it means that the collimating lens needs to be continued to move forward, and so on until the M value appears to decline, if M2 SUMMARY
[0003] The technical problem to be solved by the present application is to provide a double-lens coupling method and a silicon light engine to overcome the deficiencies in the prior art.
[0004] The technical solution of the present application to solve the above technical problems is as follows: A double-lens coupling method, comprising the following steps: S10, placing a laser chip, an optical isolator, and a silicon light chip or a thin-film lithium niobate modulator chip in sequence along the light propagation direction; S20, placing a collimating lens between the laser chip and the optical isolator, the distance between the collimating lens and the laser chip being 0.3mm±0.03mm, and moving the collimating lens up, down, left and right at the distance to maximize the photocurrent value read by the MPD integrated in the silicon optical chip or the thin film lithium niobate modulator chip, so as to align the collimating lens with the laser chip; S30, placing a converging lens between the optical isolator and the silicon optical chip or the thin film lithium niobate modulator chip, the distance between the converging lens and the silicon optical chip or the thin film lithium niobate modulator chip being 0.765mm±0.03mm, and moving the converging lens up, down, left and right at the distance to maximize the photocurrent value read by the MPD integrated in the silicon optical chip or the thin film lithium niobate modulator chip, and then fixing the converging lens; S40, moving the collimating lens up, down, left, right and front and back again to maximize the photocurrent value read by the MPD integrated in the silicon optical chip or the thin film lithium niobate modulator chip, and finally fixing the collimating lens.
[0005] The beneficial effects of the present application are: in the present application, the collimating lens is moved only in the up, down, left and right directions during the first coupling, the converging lens is also moved only in the up, down, left and right directions, and only the collimating lens is moved in the up, down, left, right, front and back directions during the second coupling, wherein, in the actual coupling process, the time consumed by the coupling in the six directions is more than 10 times the time consumed by the coupling in the four directions, even if there are two couplings in the four directions and one coupling in the six directions in the present application, the time consumed by the final double-lens coupling is still shortened by nearly 1 times compared with the time consumed by two couplings in the six directions, the coupling steps are simple, the coupling efficiency is high, the final performance of the product is good, and the MPD photocurrent value can reach the real maximum.
[0006] On the basis of the above technical solutions, the present application can also be improved as follows.
[0007] Further, the image recognition method is used to determine the distance between the collimating lens and the laser chip in S20.
[0008] Further, the image recognition method is used to determine the distance between the converging lens and the silicon optical chip or the thin film lithium niobate modulator chip in S30.
[0009] Further, the CCD camera is used for image acquisition in the image recognition method.
[0010] Further, the UV glue is used to fix the converging lens in S30.
[0011] Further, the UV glue is used to fix the collimating lens in S40.
[0012] Further, the laser chip is a DFB chip.
[0013] Based on the above technical solution, the application further provides a silicon light engine, comprising: a laser chip, a collimating lens, an optical isolator, a converging lens and a silicon light chip or a thin film lithium niobate modulator chip which are coupled in sequence along the light propagation direction, and the collimating lens and the converging lens are coupled by using the above-mentioned double-lens coupling method.
[0014] The above-mentioned further beneficial effect is that the final performance of the product is good, and the MPD photocurrent value can reach the real maximum.
[0015] Further, the laser chip is fixed on a ceramic heat sink.
[0016] Further, the first chip is coupled with the optical fiber array. BRIEF DESCRIPTION OF DRAWINGS
[0017] Figure 1 The light path diagram related to S20 in the application; Figure 2 The light path diagram related to S30 in the application; Figure 3 The light path diagram related to S40 in the application; Figure 4 The top view of the silicon light engine in the application; Figure 5 The front view of the silicon light engine in the application; Figure 6 The simulation diagram, wherein the abscissa represents the distance between the collimating lens and the laser chip, the ordinate represents the distance between the converging lens and the silicon light chip or the thin film lithium niobate modulator chip, the unit is mm, the color represents the coupling efficiency, and the redder the color is, the higher the coupling efficiency is.
[0018] In the drawings, the components represented by each reference numeral are listed as follows: 1, laser chip, 2, optical isolator, 3, silicon light chip or thin film lithium niobate modulator chip, 4, collimating lens, 5, converging lens, 6, ceramic heat sink, 7, optical fiber array. DETAILED DESCRIPTION
[0019] The principles and characteristics of the application are described below in combination with the drawings, and the examples are only used to explain the application and are not used to limit the scope of the application.
[0020] Example 1 As shown in the following figure, a double-lens coupling method comprises the following steps: Figures 1-6 S10, the laser chip 1, optical isolator 2 and silicon optical chip or thin film lithium niobate modulator chip 3 are placed in the light propagation direction in turn, that is, the laser chip 1, optical isolator 2 and silicon optical chip or thin film lithium niobate modulator chip 3 are coupled in the light propagation direction in turn; S20, a collimating lens 4 is placed between the laser chip 1 and the optical isolator 2, wherein the distance between the collimating lens 4 and the laser chip 1 is L1, L1 is 0.3mm±0.03mm, preferably 0.3mm, and the error is ±0.03mm. The reason for choosing 0.3mm is that the light spot is converged at this time, and the light spot is moderate, much larger than the light spot of the silicon optical chip or the thin film lithium niobate modulator chip 3, it is easier to find light, and the collimating lens 4 is not changed at this distance (L1), and the collimating lens 4 is moved up, down, left and right (i.e. four directions). In the embodiment, the front and back directions of the collimating lens 4 are defined as the direction of approaching and moving away from the laser chip 1 along the optical axis, so that the photocurrent value read by the MPD integrated in the silicon optical chip or the thin film lithium niobate modulator chip 3 is maximum, and the collimating lens 4 is aligned with the laser chip 1 at this time; S30, a converging lens 5 is placed between the optical isolator 2 and the silicon optical chip or the thin film lithium niobate modulator chip 3, the distance between the converging lens 5 and the silicon optical chip or the thin film lithium niobate modulator chip 3 is L2, L2 is 0.765mm±0.03mm, preferably 0.765mm, and the error is ±0.03mm. At this time, the converging lens 5 is also very good coupling, the light spot is moderate, and the converging lens 5 is not changed at this distance (L2), and the converging lens 5 is moved up, down, left and right (i.e. four directions). In order to make the photocurrent value read by the MPD integrated in the silicon optical chip or the thin film lithium niobate modulator chip 3 maximum, and then fix the converging lens 5; S40, move the collimating lens 4 up, down, front, back, left and right (i.e. six directions) again, so that the photocurrent value read by the MPD integrated in the silicon optical chip or the thin film lithium niobate modulator chip 3 is maximum, and finally fix the collimating lens 4. Since the distance from the collimating lens 4 to the laser chip 1 and the distance from the converging lens 5 to the silicon optical chip or the thin film lithium niobate modulator chip 3 affect each other, see Figure 6 Therefore, the coupling collimating lens 4 is moved for the second time after the converging lens 5 is fixed. Since the position of the converging lens 5 changes, and when it is fixed, the photocurrent value read by the MPD will have a value M, the position of the collimating lens 4 also changes, so the photocurrent value corresponding to the collimating lens 4 also has a unique maximum value. Therefore, the maximum photocurrent value read by the MPD in S30 is not the final maximum (since the distance from the collimating lens 4 to the laser chip 1 is not optimal at this time), so S40 is performed again. At this time, it is the only maximum.
[0021] The actual distance theoretical logic is: The distance tolerance range of the collimating lens 4 and the laser chip 1 is small, the distance range of the two is 0.268mm±0.018mm, that is, the lower limit value is 0.25mm, the upper limit value is 0.286mm, the tolerance range is ±0.018mm (0.286mm-0.25mm=0.036mm, divided by 2 is 0.018mm), that is, in the range, the coupling efficiency ≥93% can be achieved by adjusting the distance of the converging lens 5 to the silicon optical chip or the thin film lithium niobate modulator chip 3, the minimum distance of the collimating lens 4 from the laser chip 1 is 0.25mm, which is because: in order to avoid the UV glue under the collimating lens 4 from spilling and sticking to the ceramic heat sink 6 under the laser chip 1, if the collimating lens 4 sticks to the ceramic heat sink 6, it will cause reliability failure (at high and low temperatures, the glue expands and tilts the lens), because the tolerance is too small, it cannot be automatically placed by image recognition (CCD recognition), in the present application, when the collimating lens 4 is coupled for the first time, the distance between the collimating lens 4 and the laser chip 1 is selected as 0.3mm±0.03mm, which is because: 0.33mm is the maximum position when the collimating lens 4 is inserted alone (the spot is smallest at the maximum position, and the maximum light current value is read by the MPD), that is, it corresponds to the maximum unique position of the collimating lens 4 in the comparison file, because the collimating lens 4 is not inserted at the maximum position in the present application, but is inserted at a position with a distance of 0.3mm±0.03mm from the laser chip 1, that is, close to the maximum position, the spot is relatively large at this time, because the spot is relatively large, the coupling light is fast; when the collimating lens 4 and the converging lens 5 are inserted, according to theoretical calculation and actual test, the distance between the collimating lens 4 and the laser chip 1 is 0.2567mm, at this time, the spot is collimated light.
[0022] The distance tolerance range of the converging lens 5 and the silicon optical chip or the thin film lithium niobate modulator chip 3 is large, the distance range of the two can be 0.765mm±0.093mm, that is, the lower limit value is 0.672mm, the upper limit value is 0.858mm, the tolerance range is ±0.093mm (0.858mm-0.672mm=0.186mm, divided by 2 is 0.093mm), that is, in the range, the coupling efficiency ≥93% can be achieved by adjusting the distance of the collimating lens 4 to the laser chip 1, and the present application selects 0.765mm±0.03mm instead of 0.765mm±0.093mm, which can reduce the coupling times, and the distance range can cover the image recognition error (CCD recognition accuracy).
[0023] The collimating lens 4 is only moved in the up, down, left and right directions in the first coupling, the converging lens 5 is only moved in the up, down, left and right directions, and the collimating lens 4 is only moved in the up, down, front, back, left and right directions in the second coupling, wherein, in the actual coupling process, the time consumed by the coupling in the six directions is more than 10 times the time consumed by the coupling in the four directions, even if there are two times of coupling in the four directions and one time of coupling in the six directions in the present application, the time consumed by the final double-lens coupling can still be shortened by nearly 1 time compared with the time consumed by two times of coupling in the six directions, the coupling steps are simple, the coupling efficiency is high, the final performance of the product is good, and the MPD photocurrent value can reach the real maximum.
[0024] Embodiment 2 As shown in Figure 1 , Figure 2 , Figure 3 , the present embodiment is a further improvement on the basis of embodiment 1, and the specific improvements are as follows: The image recognition method is used to determine the distance between the collimating lens 4 and the laser chip 1 in S20, and the image recognition method is also used to determine the distance between the converging lens 5 and the silicon optical chip or the thin-film lithium niobate modulator chip 3 in S30, which can cover the precision error of ±0.03 mm, and the CCD camera is used for image acquisition in the image recognition method.
[0025] Embodiment 3 As shown in Figure 5 , the present embodiment is a further improvement on the basis of embodiment 1 or 2, and the specific improvements are as follows: The converging lens 5 is fixed by the point UV glue in S30, and the collimating lens 4 is also fixed by the point UV glue in S40.
[0026] Embodiment 4 As shown in Figure 4 , Figure 5 , the present embodiment is a further improvement on the basis of embodiment 1 or 2 or 3, and the specific improvements are as follows: The laser chip 1 is preferably a DFB chip.
[0027] Embodiment 5 As shown in Figure 4 , Figure 5As shown, a silicon light engine comprises: a laser chip 1, a collimating lens 4, an optical isolator 2, a converging lens 5 and a silicon light chip or a thin film lithium niobate modulator chip 3, wherein the laser chip 1, the collimating lens 4, the optical isolator 2, the converging lens 5 and the silicon light chip or the thin film lithium niobate modulator chip 3 are coupled in sequence along the light propagation direction, and the emitted light emitted by the laser chip 1 is coupled into the silicon light chip or the thin film lithium niobate modulator chip 3 after passing through the collimating lens 4, the optical isolator 2 and the converging lens 5 in sequence; for the coupling of the collimating lens 4 and the converging lens 5, the double-lens coupling method in any one of embodiments 1-4 is adopted for coupling.
[0028] Furthermore, the laser chip 1 is fixed on a ceramic heat sink 6, the silicon light chip or the thin film lithium niobate modulator chip 3 is coupled with a fiber array 7, and the light emitted by the silicon light chip or the thin film lithium niobate modulator chip 3 is coupled into the fiber array 7.
[0029] Although the embodiments of the present application have been shown and described above, it should be understood that the above-mentioned embodiments are exemplary and should not be construed as limiting the present application, and those of ordinary skill in the art can make changes, modifications, replacements and variations to the above-mentioned embodiments within the scope of the present application.
Claims
1. A dual lens coupling method, characterized by, It comprises the following steps: S10, placing the laser chip (1), the optical isolator (2) and the silicon optical chip or the thin film lithium niobate modulator chip (3) in sequence along the light propagation direction; S20, placing a collimating lens (4) between the laser chip (1) and the optical isolator (2), the distance between the collimating lens (4) and the laser chip (1) is 0.3mm±0.03mm, and the collimating lens (4) is kept unchanged at the distance, the collimating lens (4) is moved up, down, left and right to make the integrated MPD of the silicon optical chip or the thin film lithium niobate modulator chip (3) read the maximum photocurrent value, and the collimating lens (4) is aligned with the laser chip (1); S30, placing a converging lens (5) between the optical isolator (2) and the silicon optical chip or the thin film lithium niobate modulator chip (3), the distance between the converging lens (5) and the silicon optical chip or the thin film lithium niobate modulator chip (3) is 0.765mm±0.03mm, and the converging lens (5) is kept unchanged at the distance, the converging lens (5) is moved up, down, left and right to make the integrated MPD of the silicon optical chip or the thin film lithium niobate modulator chip (3) read the maximum photocurrent value, and then the converging lens (5) is fixed; S40, moving the collimating lens (4) up, down, front, back, left and right again to make the integrated MPD of the silicon optical chip or the thin film lithium niobate modulator chip (3) read the maximum photocurrent value, and finally fixing the collimating lens (4).
2. The method of claim 1, wherein, The image recognition method is used to determine the distance between the collimating lens (4) and the laser chip (1) in S20.
3. The method of claim 1, wherein, The image recognition method is used to determine the distance between the converging lens (5) and the silicon optical chip or the thin film lithium niobate modulator chip (3) in S30.
4. A method of double lens coupling according to claim 2 or 3, characterized in that, The CCD camera is used for image acquisition in the image recognition method.
5. The method of claim 1, wherein, The converging lens (5) is fixed by UV glue in S30.
6. The method of claim 1, wherein, The collimating lens (4) is fixed by UV glue in S40.
7. The method of claim 1, wherein, The laser chip (1) is a DFB chip.
8. A silicon light engine characterized by, It comprises: The laser chip (1), the collimating lens (4), the optical isolator (2), the converging lens (5) and the silicon optical chip or the thin film lithium niobate modulator chip (3) are coupled in sequence along the light propagation direction, and the collimating lens (4) and the converging lens (5) are coupled by the double lens coupling method of any one of claims 1-7.
9. The silicon light engine of claim 8, wherein, The laser chip (1) is fixed on the ceramic heat sink (6).
10. The silicon light engine of claim 8, wherein, The silicon optical chip or the thin film lithium niobate modulator chip (3) is coupled with the fiber array (7).