Silicon photonic device coupling method and system

Abstract

The application discloses a silicon optical device coupling method and system, which comprises the following steps: presetting the relative position between a first optical element and a second target device, and controlling the gap distance of the relative position within a preset gap value; in a preset plane, taking a predicted coupling center as a starting point, performing photoelectric detection scanning based on a first preset path to determine an initial light spot position; based on the initial light spot position, performing at least twice coupling scanning based on a second preset path to determine a final fine coupling position; based on the final fine coupling position, acquiring and recording corresponding optical parameters and position parameters, and performing performance index detection to determine whether the process requirement is met; if not, repeating the above steps until the process requirement is met. The application realizes high efficiency, high precision and high reliability of the silicon optical device coupling process through visual non-contact gap control and a combination of scanning modes of a Chinese character 'hui' and a cross.

Description

[0001] This application is a divisional application of the invention patent application with application number CN202610246296.8, entitled "A Coupling Method and System for Silicon Photonic Devices", and the parent application was filed on March 2, 2026. Technical Field

[0002] This invention belongs to the technical field of optical communication manufacturing and packaging, specifically relating to a silicon photonics device coupling method and system. Background Technology

[0003] In silicon photonics modules, especially in the packaging of receiver optical components (such as RXFA), the axial gap and lateral alignment accuracy between the fiber end face, lens and photodetector (PD) chip are key factors that determine optical coupling efficiency and device performance.

[0004] Traditional control methods often employ mechanical probe contact measurement or simple Z-axis mechanical limiting. Probe contact with the optical surface may introduce particles, scratches, or organic residues, affecting optical performance. At the same time, contact force can cause microstructure deformation, which is especially sensitive in chip thinning or precision lens assembly. Furthermore, Z-axis mechanical limiting is affected by mechanical system hysteresis, temperature drift, and probe wear, making it difficult to consistently achieve gap control accuracy better than a few micrometers.

[0005] On the other hand, when performing light-finding alignment, conventional spiral or grating scanning methods are difficult to balance search efficiency and accuracy, especially in the initial signal acquisition stage. Due to the large area of ​​uncertainty in the position of the light spot, the above scanning methods need to traverse a large number of points, which takes a long time. Summary of the Invention

[0006] The purpose of this invention is to propose a silicon photonics device coupling method and system to solve the problems in the prior art.

[0007] Therefore, the present invention provides a silicon photonic device coupling method, comprising: The relative positions between the first optical element and the second target device are preset, and the gap distance between the relative positions is controlled within a preset gap value; Within the preset plane, starting from the estimated coupling center, photoelectric detection scanning is performed based on the first preset path to determine the initial spot position; Based on the initial spot position, at least two coupling scans are performed based on the second preset path, and the scanning range and step size of the first coupling are greater than the scanning range and step size of the second coupling, in order to determine the final fine coupling position; Based on the final fine coupling position, the corresponding optical parameters and position parameters are acquired and recorded, and performance index detection is performed to determine whether the process requirements are met. If not, the above steps are repeated until the process requirements are met. The step of determining the initial spot position by performing photoelectric detection scanning based on a first preset path within a preset plane, starting from the estimated coupling center, includes: controlling a multi-directional motion mechanism carrying the first optical element within the XY plane to perform photoelectric detection on the surface of the second target device using a zigzag scanning path to determine the initial spot position; the zigzag scanning path is a square closed-loop path that expands from the inside out; during the photoelectric detection scanning, the output signal of the photodetector is monitored in real time, and when the output signal value exceeds a preset trigger threshold for the first time, the scanning stops, and the current XY coordinate information is used as the initial spot position; The two coupling scans include a coarse coupling scan and a fine coupling scan, and the second preset paths of both the coarse coupling scan and the fine coupling scan are cross-shaped paths. The coarse coupling scan takes the initial spot position as the center and performs a one-dimensional linear scan in the X and Y directions to form a cross-shaped scan path and locate the optimal coarse coupling position. The fine coupling scan takes the optimal coarse coupling position as the center and performs a one-dimensional linear scan again in the X and Y directions to determine the final fine coupling position.

[0008] Preferably, the preset relative position between the first optical element and the second target device, and controlling the gap distance between the relative positions within a preset gap value, includes: The relative position image of the first optical element and the surface of the second target device is obtained by a high-resolution side-view camera; The Z-axis gap value between the surface relative position images of the first optical element and the second target device is calculated based on a preset algorithm; The multi-directional motion mechanism is controlled to move the first optical element closer to the second target device, and the Z-axis gap between the first optical element and the second target device is within a preset gap value.

[0009] Preferably, a safety distance threshold is also provided, and when the Z-axis gap between the first optical element and the second target device is less than the safety distance threshold, the multi-directional motion mechanism stops moving.

[0010] Preferably, the coarse coupling scan has a scanning range of ±100μm and a step size of 1μm; the fine coupling scan has a scanning range of ±10μm and a step size of 0.5μm.

[0011] A second aspect of the present invention provides a silicon photonics device coupling system, comprising: A visual gap control module is used to monitor the Z-axis distance between the first optical element and the second target device in real time to prevent collisions. A multi-directional motion module is used to carry and move the first optical element; The optical signal detection module is used to acquire the photocurrent or voltage signal output by the silicon photonics device in real time. The anti-collision protection module, independent of the visual gap control module, is used for non-contact measurement of the Z-axis gap between the first optical element and the second target device; A platform module for supporting the second target device; The central control module is electrically connected to the visual gap control module, the multi-directional motion module, the optical signal detection module, and the anti-collision protection module.

[0012] Preferably, the anti-collision protection module includes at least a laser displacement sensor, and the visual gap control module includes at least a high-resolution side-view camera.

[0013] Preferably, the first optical element is a receiving optical component, and the second target device is a PD chip.

[0014] Preferably, the multi-directional motion module includes a high-precision displacement stage with X, Y, and Z axes, and a suction nozzle is set on the Z-axis high-precision displacement stage to fix the first optical element.

[0015] Beneficial effects: 1. This invention achieves high efficiency, high precision, and high reliability in the coupling process of silicon photonic devices through visual non-contact gap control and a combination of zigzag and cross-shaped scanning. Visual control directly ensures process cleanliness and sub-micron gap accuracy, avoiding contamination and damage associated with traditional contact methods. Zigzag scanning rapidly captures the optical signal area, significantly shortening the initial search time. Furthermore, the use of coarse and fine cross-shaped scanning achieves an optimized balance between efficiency and precision, quickly converging to the optimal coupling position. Independent anti-collision protection provides an active safety barrier for the precision chip. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A flowchart of the silicon photonics device coupling method provided by the present invention.

[0018] Figure 2 This is a schematic diagram of the zigzag path in the silicon photonics device coupling method provided by the present invention.

[0019] Figure 3This is a schematic diagram of the cross-shaped coarse coupling scan and the cross-shaped fine coupling scan spot in the silicon photonics device coupling method provided by the present invention.

[0020] Figure 4 This is a schematic diagram of the silicon photonics device coupling system provided by the present invention.

[0021] In the diagram: 1. Multi-directional motion mechanism; 2. Stage; 3. Optical signal detection module; 4. Side camera; 5. Laser sensor; 6. Top camera; 7. Nozzle. Detailed Implementation

[0022] The invention will be more readily understood by referring to the following detailed description of preferred embodiments and included examples. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of conflict, the definitions in this specification shall prevail.

[0023] like Figures 1-3 As shown, a silicon photonics device coupling method includes: The relative positions between a first optical element and a second target device are preset, and the gap between these relative positions is controlled within a preset gap value. The first optical element is a receiving optical component such as a lens (FA), while the second target device is a chip, which in this application can be a PD chip. By presetting the relative positions between the first optical element and the second target device, they are kept at an initial distance, facilitating further adjustment of their distance to ensure they are close enough without contact, thus avoiding contamination of the optical surface or damage to components such as the chip. Simultaneously, when the FA and PD chip are adjusted to their initial positions, they remain parallel to each other, ensuring consistent distances at all positions, facilitating subsequent light alignment.

[0024] Within a preset plane, starting from the estimated coupling center, a photoelectric detection scan is performed based on a first preset path to determine the initial spot position. This first preset path is a U-shaped path, and its scanning path covers an area where the initial position is uncertain. The U-shaped path scans through a rectangular closed loop that expands layer by layer from the inside out or from the outside in. This trajectory is geometrically more compatible with the effective photosensitive area of ​​photodetectors (PDs) in most silicon photonic devices, which is typically rectangular or approximately rectangular. Compared to a spiral scan that expands uniformly outward from a certain point, the U-shaped path can cover the boundary of the rectangular area where the target may exist earlier with fewer scan cycles. Therefore, even with significant initial uncertainty in the spot position, it can reach the light signal for the first time with a higher probability and a shorter travel distance, achieving rapid acquisition.

[0025] Based on the initial spot position, at least two coupling scans are performed along a second preset path, with the scanning range and step size of the first coupling scan being greater than those of the second coupling scan, to determine the final fine coupling position. The coarse coupling scan, executed rapidly with a large range and step size, efficiently captures the overall distribution trend of the light signal intensity within the approximate area initially determined by the light search, quickly locating the macroscopic region where the peak is located. Although this reduces some local accuracy, the scanning speed is faster, effectively avoiding redundant dwelling in non-peak areas and laying a precise starting point for subsequent fine coupling scans. The fine coupling scan, within the peak region determined by the coarse coupling, unfolds with a small range and fine step size, performing high-density sampling in the core region where the signal is strongest. This allows for precise identification and location of the global maximum point of the light signal intensity, achieving sub-micron or even higher precision final alignment, thereby determining the final fine coupling position.

[0026] Based on the final fine coupling position, the corresponding optical parameters and position parameters are acquired and recorded. The optical parameters include the maximum light signal intensity value, and the position parameters include the corresponding XYZ coordinates and the final gap value measured by the vision system. The performance (spec) index is then checked to determine whether the process requirements are met. If not, an alarm is triggered or the process is retried according to the preset logic. That is, the parameters are adjusted and the above steps are repeated until the process requirements are met, and then the subsequent fixing process is carried out.

[0027] In one embodiment, the preset relative position between the first optical element and the second target device, and controlling the gap distance of the relative position within a preset gap value, includes: A high-resolution side-view camera acquires images of the relative positions of the first optical element and the second target device surface, i.e., images of the relative positions of the FA and PD surfaces, thereby precisely controlling the gap between them. Simultaneously, an upper camera located above can determine whether the relative positions of the FA and PD in the XY plane are aligned. This facilitates fixing the two components in subsequent calibration processes.

[0028] Based on a preset algorithm, such as edge detection or feature point matching, the Z-axis gap value between the surfaces of the first optical element and the second target device is calculated in real time and displayed on the screen. This allows operators to observe whether the gap is within the preset value, preventing them from coming into contact due to excessive distance and damaging the chip. Furthermore, this measurement method is non-contact, effectively avoiding contamination of the optical element caused by contact measurements.

[0029] The multi-directional motion mechanism is controlled to move the first optical element closer to the second target device, ensuring that the Z-axis gap between the first optical element and the second target device is within a preset gap value. While maintaining a sufficiently close distance (e.g., within 10 μm), precise position adjustment can be achieved through the sophisticated multi-directional motion mechanism, preventing collisions between the two components.

[0030] In one embodiment, a safe distance threshold is also provided. When the Z-axis gap between the first optical element and the second target device is less than the safe distance threshold, the Z-axis motion mechanism stops moving. Specifically, an independent non-contact anti-collision sensor, such as a laser displacement sensor, is used to detect abnormal proximity during the movement and immediately stop the mechanism to prevent damage to the chip. This non-contact anti-collision sensor does not participate in the closed-loop control of the gap, thus avoiding any interference from the complex algorithm adjustments, dynamic responses, or parameter tuning processes in the closed-loop control. Even if the gap control module malfunctions, the anti-collision module can still operate independently and reliably, implementing emergency braking in the event of unexpected physical proximity to provide physical protection for the optical device and the chip.

[0031] In one embodiment, the step of performing photoelectric detection scanning within a preset plane, starting from an estimated coupling center and based on a first preset path, to determine the initial spot position includes: Within the XY plane of the PD, a multi-directional motion mechanism is controlled to mount the first optical element. Specifically, the first optical element, i.e., FA, can be fixed to the multi-directional motion mechanism via a suction nozzle. Negative pressure is generated by the suction nozzle to fix the FA. Then, a U-shaped scanning path is used to efficiently perform photoelectric detection on the surface of the second target device to determine the initial light spot position. The U-shaped scanning path is as follows: Figure 2 As shown, the initial spot position is the spatial location where the first effective light signal is detected.

[0032] In one embodiment, during photoelectric detection scanning, the output signal of the photodetector is monitored in real time. When the output signal value exceeds a preset trigger threshold for the first time, the scanning stops, and the current XY coordinates are used as the initial spot position. Specifically, after the visual gap is preset, the system controls the motion platform in the XY plane to begin a zigzag scan, expanding layer by layer from the inside out, starting from the estimated coupling center. While the scanning motion continues, the optical signal detection module collects and monitors the photocurrent signal output by the photodetector (PD) in real time. The system presets a trigger threshold for determining the presence of a light signal, which is typically set to a low level slightly higher than the system noise floor. Once the real-time monitored photocurrent value exceeds the preset trigger threshold for the first time, the central control module immediately issues a command to stop the scanning motion and simultaneously records the precise coordinates of the motion platform on the XY axis at this time. These coordinates are then determined and recorded as the initial spot position. This threshold-based stop mechanism ensures that the system completes the spot region discovery with the shortest motion path and the fewest sampling points, greatly reducing the time consumed in the initial search phase.

[0033] like Figure 3 As shown, in one embodiment, the two coupling scans include a coarse coupling scan and a fine coupling scan, and the second preset path of both the coarse coupling scan and the fine coupling scan is a cross-shaped path; The coarse coupling scan, centered on the initial spot position, performs a one-dimensional linear scan in the X and Y directions, forming a cross-shaped scanning path. This quickly determines the approximate peak positions of the optical signal intensity distribution in the X and Y directions, thus locating the optimal coarse coupling position. In some embodiments, such as... Figure 3 As shown in a, the scanning range of the coarse coupling scan is ±100μm, and the step size is 1μm.

[0034] The fine coupling scan, centered on the optimal position of the coarse coupling, performs another one-dimensional linear scan in the X and Y directions. This stage employs a significantly reduced scan range and a finer step size, such as... Figure 3 As shown in b, for example, the scanning range of fine coupling scanning is ±10μm, and the step size is 0.5μm, in order to determine the final fine coupling position.

[0035] It should also be noted that during or after the fine coupling process, the vision image system can be called again to make final fine adjustments and confirmations to the Z-axis gap, ensuring that it is within the tolerance required by the process.

[0036] like Figure 4As shown, the present invention also provides a system using the above method, including a visual gap control module for non-contact measurement and feedback of the Z-axis gap between the first optical element and the second target device; wherein the visual gap control module includes a high-resolution imaging unit such as a side-view camera, thereby enabling the gap to be controlled within 10 μm, but without causing the FA and PD to come into contact or collide.

[0037] A multi-directional motion module is used to carry and move the first optical element; specifically, the multi-directional motion module includes a high-precision displacement stage with X, Y and Z axes, and a suction nozzle is set on the high-precision displacement stage with Z axis, through which the FA can be fixed.

[0038] Optical signal detection modules, such as photoelectric signal detection modules, are used to acquire photocurrent or voltage signals output by silicon photonic devices in real time. The anti-collision protection module includes non-contact ranging units such as laser displacement sensors, and is independent of the visual gap control module. It is used to non-contactly measure the Z-axis gap between the first optical element and the second target device. The stage module is used to carry the second target device, namely PD. The stage module is kept in a fixed position and the above operations are mainly performed by moving the FA. The central control module is electrically connected to the visual gap control module, the multi-directional motion module, the optical signal detection module, and the anti-collision protection module, thereby enabling the control of platform movement, signal acquisition, execution of zigzag and cross-shaped scanning algorithms, processing of visual image data, and management of the entire coupling process.

[0039] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A coupling method for silicon photonic devices, characterized in that, include: The relative positions between the first optical element and the second target device are preset, and the gap distance between the relative positions is controlled within a preset gap value; Within the preset plane, starting from the estimated coupling center, photoelectric detection scanning is performed based on the first preset path to determine the initial spot position; Based on the initial spot position, at least two coupling scans are performed based on the second preset path, and the scanning range and step size of the first coupling are greater than the scanning range and step size of the second coupling, in order to determine the final fine coupling position; Based on the final fine coupling position, the corresponding optical parameters and position parameters are acquired and recorded, and performance index detection is performed to determine whether the process requirements are met. If not, the above steps are repeated until the process requirements are met. The step of determining the initial spot position by performing photoelectric detection scanning based on a first preset path within a preset plane, starting from the estimated coupling center, includes: controlling a multi-directional motion mechanism carrying the first optical element within the XY plane to perform photoelectric detection on the surface of the second target device using a zigzag scanning path to determine the initial spot position; the zigzag scanning path is a square closed-loop path that expands from the inside out; during the photoelectric detection scanning, the output signal of the photodetector is monitored in real time, and when the output signal value exceeds a preset trigger threshold for the first time, the scanning stops, and the current XY coordinate information is used as the initial spot position; The two coupling scans include a coarse coupling scan and a fine coupling scan, and the second preset paths of both the coarse coupling scan and the fine coupling scan are cross-shaped paths. The coarse coupling scan takes the initial spot position as the center and performs a one-dimensional linear scan in the X and Y directions to form a cross-shaped scan path and locate the optimal coarse coupling position. The fine coupling scan takes the optimal coarse coupling position as the center and performs a one-dimensional linear scan again in the X and Y directions to determine the final fine coupling position.

2. The silicon photonic device coupling method according to claim 1, characterized in that, The preset relative position between the first optical element and the second target device, and controlling the gap distance between the relative positions within a preset gap value, includes: The relative position image of the first optical element and the surface of the second target device is obtained by a high-resolution side-view camera; The Z-axis gap value between the surface relative position images of the first optical element and the second target device is calculated based on a preset algorithm; The multi-directional motion mechanism is controlled to move the first optical element closer to the second target device, and the Z-axis gap between the first optical element and the second target device is within a preset gap value.

3. The silicon photonic device coupling method according to claim 2, characterized in that, A safety distance threshold is also provided. When the Z-axis gap between the first optical element and the second target device is less than the safety distance threshold, the multi-directional motion mechanism stops moving.

4. The silicon photonic device coupling method according to claim 1, characterized in that, The coarse coupling scan has a scanning range of ±100μm and a step size of 1μm; the fine coupling scan has a scanning range of ±10μm and a step size of 0.5μm.

5. A silicon photonic device coupling system, characterized in that, The silicon photonic device coupling method according to any one of claims 1-4 includes: A visual gap control module is used to monitor the Z-axis distance between the first optical element and the second target device in real time to prevent collisions. A multi-directional motion module is used to carry and move the first optical element; The optical signal detection module is used to acquire the photocurrent or voltage signal output by the silicon photonics device in real time. The anti-collision protection module, independent of the visual gap control module, is used for non-contact measurement of the Z-axis gap between the first optical element and the second target device; A platform module for supporting the second target device; The central control module is electrically connected to the visual gap control module, the multi-directional motion module, the optical signal detection module, and the anti-collision protection module.

6. The silicon photonic device coupling system according to claim 5, characterized in that, The collision protection module includes at least a laser displacement sensor, and the visual gap control module includes at least a high-resolution side-view camera.

7. The silicon photonic device coupling system according to claim 5, characterized in that, The first optical element is a receiver optical component, and the second target device is a PD chip.

8. The silicon photonic device coupling system according to claim 5, characterized in that, The multi-directional motion module includes a high-precision displacement stage with X, Y, and Z axes. A suction nozzle is set on the Z-axis high-precision displacement stage to fix the first optical element.

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