Automated coupling assembly process of DFAU with thermal compensation and silicon optical microlens array

Abstract

The application discloses a DFAU and silicon light microlens array automatic coupling assembly process with heat compensation, which comprises the following steps: fixing a silicon light bearing substrate on a temperature control bearing platform, placing a DFAU module on a multi-dimensional fine adjustment stage and preliminarily limiting; collecting optical power data of all optical channels at a first temperature and a second temperature respectively, recording optimal coupling coordinates of an optical path, calculating a thermal expansion offset vector, generating a heat compensation correction coordinate parameter and performing position compensation on the DFAU, adjusting the DFAU and the microlens array to reach a target coupling state through the multi-dimensional fine adjustment stage; after pre-tightening, a small reciprocating excitation displacement is applied, and optical power synchronous fluctuation is monitored to judge the activity allowance of the floating base; after detection, final tightening is completed, and the DFAU clamping limiting is released after high and low temperature cycle verification. Through cold and hot double reference pre-compensation and grading locking process, the application realizes stable coupling of an optical path in a wide temperature range, and is suitable for high-yield automatic mass production of CPO silicon light engine DFAU.

Description

Technical Field

[0001] This invention relates to the fields of optical communication and silicon photonics packaging technology, and in particular to an automated coupling and assembly process for a thermally compensated DFAU and a silicon photonic microlens array. Background Technology

[0002] With the explosive growth in demand for AI computing power, co-packaged optics (CPO) technology has become a mainstream solution for data center interconnects. Inside the CPO silicon photonics engine, the silicon photonics PIC chip integrates a microlens array, requiring precise optical path coupling assembly of the DFAU (Demountable Fiber Array Unit). Currently, leading companies such as Marvell and NVIDIA have clearly stated that their next-generation CPO switches will adopt the DFAU solution, making DFAU the core coupling solution for optical interconnects in the CPO era.

[0003] However, the existing DFAU coupling assembly process has the following significant shortcomings:

[0004] (1) Reliance on active alignment results in low efficiency and yield. Most existing mainstream solutions adopt active alignment, which relies on a high-precision displacement stage to adjust the relative position of the DFAU and the silicon photonic chip channel by channel. The coupling of a single silicon photonic engine takes a long time and the equipment investment cost is extremely high, making it difficult to support large-scale capacity expansion.

[0005] (2) Lack of thermal compensation mechanism, resulting in poor reliability over wide temperature range. A small number of DFAU assembly processes only pursue optical path alignment at room temperature, and thermal compensation reference calibration is not introduced in the assembly process. In the wide operating temperature range of -40℃ to 100℃, the optical path is affected by the mismatch of the thermal expansion coefficients between the silicon substrate and the DFAU base, resulting in submicron-level drift and severe deterioration of coupling loss.

[0006] (3) Mechanical positioning and optical alignment are separated, and the assembly datum is not unified. The traditional coupling process separates mechanical positioning assembly and optical alignment into two independent processes, and there is no optical path collaborative calibration process. The datum of the DFAU guide locking mechanism, the thermal compensation floating base and the microlens array are not unified, resulting in low assembly yield and poor consistency of insertion loss in multiple channels.

[0007] (4) After locking, the floating structure is prone to jamming and loses its thermal compensation capability. In conventional processes, after assembly and locking, the floating structure is easily rigidly locked, the thermal compensation floating gap disappears, the temperature drift suppression capability is lost, and the coupling loss continues to deteriorate under long-term high and low temperature cycle conditions.

[0008] In summary, the industry urgently needs an integrated automated coupling assembly solution that takes into account the detachable characteristics of DFAU, precise optical path alignment, thermal compensation floating margin retention, and high and low temperature optical path stability. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide an automated coupling and assembly process for a thermally compensated DFAU and a silicon photonic microlens array, addressing the shortcomings of the prior art.

[0010] The technical solution of this invention to solve the above-mentioned technical problems is as follows: An automated coupling and assembly process for a thermally compensated DFAU and a silicon photonic microlens array, comprising the following steps:

[0011] The silicon photonics carrier substrate equipped with a silicon photonics PIC chip and microlens array is fixed on a temperature-controlled carrier platform, and the DFAU module pre-assembled with a thermal compensation floating base is placed on a multi-dimensional fine-tuning stage and initially positioned.

[0012] Optical power data of all optical channels are collected at the first temperature and the second temperature respectively. The optimal coupling coordinates of the optical path at the first temperature and the second temperature are recorded. The thermal expansion offset vector is calculated based on the difference between the optimal coordinates at the two temperatures, and thermal compensation correction coordinate parameters are generated.

[0013] The position of the DFAU is compensated according to the thermal compensation correction coordinate parameters, and the DFAU and the microlens array are made to reach the target coupling state through the multidimensional motion adjustment of the multidimensional fine-tuning stage.

[0014] The drive locking actuator pre-locks the DFAU housing with a first clamping force range;

[0015] In the pre-locked state, a small reciprocating excitation displacement is applied to the thermal compensation floating base, while continuously collecting the optical power values ​​of each path. The presence of synchronous fluctuations in optical power is used to determine whether the thermal compensation floating base has a margin of movement.

[0016] After the movement margin test is qualified, control the locking actuator to continue feeding, and complete the final locking with a second clamping force range greater than the first clamping force range;

[0017] The temperature control platform is started to perform high and low temperature cycle test. During the entire cycle, the coupling loss values ​​of each channel are continuously collected to determine whether the fluctuation of coupling loss of each channel exceeds the preset threshold. If any channel exceeds the preset threshold, it is judged as unqualified and an alarm is issued or the system is automatically unlocked and returned to debugging.

[0018] After the high and low temperature verification is passed, the DFAU clamping limit is released, the assembled components are removed, and the assembly data is bound to the product identification information for storage.

[0019] Based on the above technical solution, the present invention can be further improved as follows:

[0020] Further: The first temperature is 20℃~30℃, and the holding time is 3~8 minutes; the second temperature is 80℃~90℃, and the holding time is 5~12 minutes.

[0021] The beneficial effects of the above-mentioned further scheme are as follows: By acquiring the optimal coupling coordinates of the optical path at two characteristic temperature points—room temperature (20℃~30℃) and high temperature (80℃~90℃)—it is possible to accurately capture the three-dimensional offset vector caused by the difference in thermal expansion coefficients between the silicon photonics substrate and the DFAU base, providing a precise data basis for subsequent thermal compensation correction. The holding times of 3~8 minutes and 5~12 minutes ensure sufficient uniformity of the substrate temperature field, avoiding measurement errors caused by temperature non-uniformity.

[0022] Furthermore: When collecting optical power data for all optical channels, the following is also included:

[0023] Point scanning was performed at temperatures ranging from -45℃ to -35℃ to collect optical path offset data under low-temperature conditions and to establish a full-temperature-range compensation model.

[0024] The beneficial effect of the above-mentioned further solutions is that by adding point scanning at low temperatures (-45℃ to -35℃), the entire operating temperature range (-40℃ to 100℃) can be covered, establishing a full-temperature compensation model. This makes the process not only suitable for room temperature mass production scenarios, but also adaptable to industrial and automotive-grade products with stringent requirements for wide-temperature reliability, further broadening the applicability of the process.

[0025] Further: The step of performing position compensation on the DFAU based on the thermal compensation correction coordinate parameters, and adjusting the DFAU and the microlens array to achieve the target coupling state through multi-dimensional motion adjustment of the multi-dimensional fine-tuning stage, specifically includes the following steps:

[0026] The multi-dimensional fine-tuning stage is driven to perform displacement compensation according to the thermal compensation correction coordinate parameters, so that the front guide pin of DFAU is inserted along the guide hole on the side of the silicon photonics substrate to complete the mechanical coarse positioning; wherein, the moving feed speed of the multi-dimensional fine-tuning stage is not higher than 5μm / s;

[0027] A light signal is input to the input terminal of the silicon photonics chip. When a valid light signal is detected, coarse alignment is determined to be complete.

[0028] The multi-dimensional fine-tuning stage is driven to perform point scanning in multiple dimensions with sub-micron step sizes, collect the optical power of all channels in real time, search for the global optical power peak point, and determine that the target coupling state is reached when the optimal coupling point is reached. The movement stops and the current optimal coupling coordinates are stored. Specifically, the optimal coupling point is determined to be reached when the average optical power fluctuation of 20 to 40 consecutive sets of sampling data is less than 0.01dB to 0.03dB. The sub-micron step size is 0.05μm to 0.2μm, and the scanning dimensions include five dimensions: X-axis, Y-axis, Z-axis, horizontal deflection, and pitch deflection.

[0029] The beneficial effects of the above-mentioned further scheme are as follows: by using the thermally compensated coordinate parameters as the displacement reference for coarse positioning, a three-stage progressive alignment strategy of "thermal compensation pre-calibration, mechanical coarse positioning, and optical fine coupling" is realized. During the coarse positioning stage, the speed does not exceed 5μm / s, effectively preventing hard contact of the guide pins from scratching the device. During the fine coupling stage, a submicron step size of 0.05μm to 0.2μm is used for helical scanning in five dimensions, coupled with a power fluctuation judgment threshold of 0.01dB to 0.03dB, ensuring a steady-state alignment accuracy better than 0.3μm. Simultaneously, optical coupling calibration and mechanical positioning reference are completed collaboratively in the same process, eliminating the multi-reference deviation problem caused by traditional step-by-step assembly.

[0030] Further: The first clamping force range is 0.8 N to 1.2 N, and after pre-locking, it is left to stand for 20 to 40 seconds to eliminate mechanical contact stress; the second clamping force range is 2.5 N to 3.5 N, and the locking adopts a constant pressure control mode, and after locking, it is left to stand for 50 to 70 seconds to stabilize the internal mechanical stress.

[0031] The beneficial effects of the above-mentioned further solution are as follows: The phased locking strategy of "pre-locking, stress release, and final locking" is employed. During the pre-locking stage, the low clamping force of 0.8N to 1.2N is used only for initial fixation, and a 20-40 second resting period allows for full release of mechanical contact stress, preventing optical path misalignment caused by stress concentration. The constant pressure control mode of 2.5N to 3.5N during the final locking stage ensures locking reliability while preventing instantaneous impact forces from compressing the thermally compensated floating base. This differentiated design of the two clamping forces addresses both the requirements of assembly stability and thermal compensation protection.

[0032] Further: The micro reciprocating excitation displacement is 0.3μm to 0.8μm, and it is continuously reciprocated 2 to 5 times. If the optical power changes continuously with the micro displacement excitation, it is determined that the thermal compensation floating base has a margin of movement; if the optical power remains unchanged under the micro displacement excitation, it is determined that the thermal compensation floating base is locked. At this time, the locking actuator is slightly loosened, and the pre-locking state is readjusted before the micro reciprocating excitation displacement detection is performed again. The number of times the pre-locking state is readjusted is 1 to 3 times. If it still fails to pass after more than 3 times, an alarm is triggered.

[0033] The beneficial effects of the above-mentioned further solution are as follows: Using "optical path performance" as a means of detecting "mechanical condition"—by applying a tiny reciprocating excitation displacement of 0.3μm to 0.8μm, the synchronous fluctuation of optical power is used to determine whether the floating base has sufficient mobility. This detection logic links the optical path coupling state with the mechanical locking state in real time, enabling immediate detection of floating base jamming during the locking process, preventing defective products from entering subsequent processes. The 1-3 retry mechanism and over-limit alarm mechanism further improve the fault tolerance and operability of the process.

[0034] Furthermore: the thermally compensated floating base retains an active gap of ≥0.5μm after final locking; the DFAU design allows for ≥300 repeated non-destructive insertion and removal cycles.

[0035] The beneficial effects of the above-mentioned further solutions are: the activity gap can ensure that the thermal compensation floating base still has sufficient passive thermal drift compensation capability after final locking, and the coupling loss remains stable under long-term high and low temperature cycle conditions; the number of repeated non-destructive plugging and unplugging fully meets the needs of rapid on-site operation and maintenance of CPO switches, which is clearly different from the traditional permanent bonding FA process and significantly reduces operation and maintenance costs.

[0036] Further: The temperature range of the high and low temperature cycling test is -20℃ to 95℃, the heating rate and cooling rate are both 2℃ / min to 5℃ / min, and the duration of a single complete cycle is ≤15 minutes; the preset threshold is 0.3dB to 0.8dB, and if the fluctuation of coupling loss in any channel exceeds the preset threshold, it is determined that the thermal drift exceeds the standard. At this time, the system will automatically unlock and return to the step of re-adjusting the DFAU position based on the thermal compensation correction coordinate parameters.

[0037] The beneficial effects of the above-mentioned further solutions are: The high and low temperature verification process is moved forward to the assembly fixture for online completion, eliminating the need to transfer components to an independent testing station and shortening the production line cycle. The temperature range of -20℃ to 95℃ covers the full operating temperature range of industrial-grade products, and the temperature change rate of 2℃ / min to 5℃ / min and rapid cycle time of ≤15 minutes enable efficient screening within the production line cycle time. The loss fluctuation threshold of 0.3dB to 0.8dB accurately identifies defective products with excessive thermal drift, and the automatic unlocking and return for readjustment mechanism enables online repair of defective products, reducing scrap losses.

[0038] The present invention also provides an automated coupling and assembly system for a thermally compensated DFAU and a silicon photonic microlens array, used to implement the aforementioned assembly process, characterized in that it includes:

[0039] Temperature-controlled support platform, used to support and control the temperature of silicon photonics substrate;

[0040] A multi-dimensional fine-tuning stage with multi-dimensional adjustment capabilities is used to support the DFAU module and realize precise movements in five dimensions: X-axis, Y-axis, Z-axis, horizontal deflection, and pitch deflection.

[0041] A multi-channel optical power detection module is used to collect the output optical power of each optical channel in real time;

[0042] Infrared temperature measurement module is used to monitor the temperature of the substrate and coupling area in real time;

[0043] A locking actuator is used to apply a controllable clamping force to the DFAU housing to achieve graded locking;

[0044] The host computer control system is used to store the optimal coupling coordinates of the optical path, calculate the thermal expansion offset vector, generate thermal compensation correction coordinate parameters and send them to the motion control system, as well as record and store assembly data.

[0045] The beneficial effects of this invention are:

[0046] (1) Pre-compensate for thermal mismatch error and improve wide-temperature reliability. Through the cold and hot dual-reference pre-scanning process, the optimal coupling coordinates of the optical path are collected at room temperature (20℃~30℃) and high temperature (80℃~90℃), the thermal expansion offset vector is calculated and pre-compensated during the assembly stage. This solves the problem that the traditional process can only guarantee room temperature performance and the optical path drift is serious in high and low temperature environments, and ensures the stable optical performance of the silicon photonic engine in the full operating temperature range (-40℃~100℃);

[0047] (2) The graded locking process effectively protects the thermal compensation function. The graded locking process of "pre-locking (0.8N~1.2N), stress release (20~40 seconds), movement margin detection and final locking (2.5N~3.5N)" is adopted, and the constant pressure control mode is used to effectively avoid excessive locking force causing the floating base to jam. This ensures that after the DFAU is assembled, the thermal compensation floating base retains a movement gap of ≥0.5μm, and the coupling loss remains stable under long-term high and low temperature cycle conditions.

[0048] (3) Floating gap is detected online by optical power to ensure locking quality. By applying a small reciprocating excitation displacement of 0.3μm to 0.8μm and monitoring the synchronous fluctuation of optical power, it is determined whether the floating base has a margin of movement. The "optical path performance" is used as the detection method of "mechanical state", which realizes the real-time quantitative judgment of locking quality and avoids the hidden danger that the floating structure is rigidly locked and cannot be detected in the traditional process;

[0049] (4) Unifying optical path and mechanical reference significantly improves assembly yield. Optical coupling calibration and mechanical positioning reference calibration are completed in the same process, eliminating the multi-reference deviation problem caused by traditional step assembly. Submicron level (0.05μm~0.2μm step size, steady-state accuracy ≤0.3μm) five-dimensional precision coupling scanning effectively reduces the defect rate of inconsistent insertion loss in multi-channel DFAU, making it suitable for mass production;

[0050] (5) Enables online pre-inspection, saving production costs. After assembly, high and low temperature verification of -20℃ to 95℃ can be carried out directly in the coupling tooling, without the need to transfer to the back-end independent testing station, shortening the production line cycle. The loss fluctuation threshold of 0.3dB to 0.8dB can screen out defective products with excessive thermal drift in advance, and the mechanism of automatic unlocking and return for readjustment realizes online repair of defective products, reducing waste in subsequent semi-finished product processing;

[0051] (6) Adaptable to pluggable maintenance architecture. The entire assembly process is designed for the pluggable structure of DFAU, supporting ≥300 repeated non-destructive plugging and unplugging. After assembly, the clips can be unlocked and the fiber array can be removed for individual replacement at any time, meeting the rapid maintenance needs of CPO switches in the field, which is clearly different from the traditional permanent bonding FA coupling process. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the automated coupling and assembly process of a thermally compensated DFAU and a silicon photonic microlens array according to an embodiment of the present invention. Detailed Implementation

[0053] The principles and features of the present invention are 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.

[0054] The DFAU (Demountable Fiber Array Unit) described in this invention refers to a fiber array assembly with pluggable functionality. Its key difference from traditional permanently bonded FA (Fiber Array) lies in the fact that the DFAU achieves a reusable pluggable connection with the silicon photonics engine through a precision mechanical locking mechanism, supporting on-site maintenance and replacement. The silicon photonics microlens array described in this invention refers to a microlens array integrated on the end face of a silicon photonics PIC chip, used to achieve mode field adaptation and optical path coupling between the silicon photonics waveguide and the DFAU fiber array.

[0055] The thermally compensated floating base described in this invention refers to an elastic floating structure pre-assembled on the DFAU module. By maintaining a micron-level movable gap, it can adaptively absorb the relative displacement caused by the mismatch in thermal expansion coefficients between the silicon photonic substrate and the DFAU base when the temperature changes, thereby suppressing optical path drift.

[0056] This embodiment uses the DFAU coupling assembly of a silicon photonics engine for a CPO switch as an example to describe the method and system of the present invention in detail. This silicon photonics engine integrates a 16-channel microlens array, operates in a temperature range of -40℃ to 100℃, and requires coupling insertion loss <1.5dB / channel and insertion loss fluctuation <0.5dB across the entire temperature range.

[0057] like Figure 1 As shown, the automated coupling and assembly process of the thermally compensated DFAU and silicon photonic microlens array of the present invention is implemented based on an automated multi-dimensional precision coupling fixture. The fixture consists of: a substrate support platform with temperature control function, a high-precision multi-dimensional motion stage, a multi-channel optical power detection module, an infrared temperature measurement module, an electrically controlled locking actuator, and a host computer system. Before the formal assembly operation, the fixture performs a power-on self-test, optical path calibration, and force sensor zero-point calibration to confirm that all equipment communication is normal and the motion axis has returned to zero before starting the product assembly process.

[0058] The operator smoothly places the silicon photonics substrate, equipped with a silicon photonics PIC chip and microlens array, onto the temperature-controlled support platform and activates the vacuum adsorption device to fix the substrate. The operator visually confirms that the substrate edges are aligned with the positioning guards and that the silicon photonics PIC chip and microlens array are free from damage or contamination. Then, the DFAU module, pre-assembled with a thermally compensated floating base, is placed inside the positioning slot of the multi-dimensional fine-tuning stage, and the simple side-mounted limiting fixture on the stage is activated for initial positioning. After clamping, the host computer reads the current substrate temperature from the infrared temperature measurement module. The operator waits for the substrate temperature to stabilize, with a temperature fluctuation range of ≤±0.3℃, before proceeding to the next step.

[0059] The host computer control system controls the temperature control platform to heat up to the 25°C ambient temperature reference temperature and maintains the temperature for 5 minutes. After the temperature maintenance is completed, the multi-dimensional fine-tuning stage drives the DFAU module to move to the preset initial detection position. The multi-channel optical power detection module sequentially collects the optical power data of all 16 optical channels and records the initial relative optimal coupling coordinates between the microlens array and the DFAU fiber array under the 25°C operating condition.

[0060] After data acquisition, the temperature-controlled carrier platform is heated to 85°C to simulate high-temperature conditions and kept at that temperature for 8 minutes to ensure uniform temperature of the silicon photonics carrier substrate and DFAU module. Once the temperature stabilizes, the multi-dimensional fine-tuning stage is driven again to perform point scanning and record the optimal coupling coordinates of the optical path under 85°C conditions.

[0061] The host computer compares the optimal coordinate difference between the two sets of temperatures, calculates the X, Y, and Z axis offset vectors caused by the thermal expansion of the silicon photonics substrate and DFAU base material, generates thermal compensation correction coordinate parameters, and automatically sends them to the host computer control system as the basic offset compensation amount for subsequent alignment.

[0062] Optionally, when collecting optical power data for all optical channels, additional point scanning is performed at -45℃ to -35℃ to collect low-temperature optical path offset data, establish a full-temperature compensation model, and further broaden the stable operating temperature range of the product to -40℃ to 100℃.

[0063] The multi-dimensional fine-tuning stage performs displacement compensation based on the thermal compensation correction coordinate parameters obtained in the previous step, driving the DFAU module to move slowly forward. The DFAU front guide pin is inserted along the guide hole on the side of the silicon photonics substrate, completing the coarse positioning at the mechanical level. A movement speed limit is set during the movement process, with a single feed speed not exceeding 5μm / s to prevent the guide pin from scratching the device through hard contact.

[0064] After the guide is inserted into place, the external continuous light source inputs a standard optical signal to the input terminal of the silicon photonics PIC chip. The multi-channel optical power detection module reads the output optical power of each channel in real time. The host computer continuously monitors the trend of optical power change. When any channel detects a valid optical signal, it determines that the coarse alignment is complete and locks the current coarse positioning coordinates.

[0065] The fine coupling search program is initiated, and the multi-dimensional fine-tuning stage performs a spiral point scan in five dimensions—X-axis, Y-axis, Z-axis, horizontal deflection, and pitch deflection—with a minimum feed step of 0.1 μm. The multi-channel optical power detection module continuously collects the optical power of all 16 channels. The host computer control system program calculates the average coupling efficiency of all channels in real time and continuously searches for the global optical power peak point.

[0066] When the average optical power fluctuation is less than 0.02dB across 30 consecutive sets of sampled data, the optimal coupling point is determined to have been reached. The multidimensional fine-tuning stage pauses its movement, and the host computer control system stores the current optimal coupling coordinates, maintaining the stage position stationary.

[0067] The host computer control system issues a command to activate the electrically controlled locking actuator, driving the locking latch to slowly move towards the DFAU module housing. The host computer control system retrieves preset pre-locking parameters, controlling the clamping force to be stably maintained within the range of 0.8N to 1.2N. After reaching the set clamping force, the locking mechanism pauses feeding, without fully locking. After the pre-locking operation is completed, it is left to stand for 30 seconds to eliminate minor stress deformation caused by mechanical contact, preventing stress release from causing optical path position shift.

[0068] After the settling period, the gap detection process is initiated. A tiny reciprocating excitation displacement of 0.5 μm is applied to the X-axis of the multi-dimensional fine-tuning stage, and this is repeated three times. At the same time, the multi-channel optical power detection module continuously collects the optical power values ​​of each channel.

[0069] Judgment Rules: If the optical power exhibits continuous and smooth fluctuations synchronously during the minute displacement of the multidimensional fine-tuning stage, it indicates that the thermal compensation floating base has sufficient margin of movement, meeting the design requirements (≥0.5μm). If the optical power shows no significant change, it indicates that the thermal compensation floating base is rigidly locked and the gap has disappeared, which is considered defective. If the minute excitation displacement can be absorbed by the floating base, the optical path geometry remains unchanged, and the optical power is stable. Conversely, if the base is jammed, the excitation displacement will be directly transmitted to the optical path, causing optical power fluctuations. When a defective result occurs, the host computer control system automatically controls the locking actuator to slightly loosen the latch and re-execute the elastic pre-locking process, allowing a maximum of 3 repeated adjustments. If the 3 adjustments still fail to meet the requirements, the system alarms, and the DFAU module is manually removed to check for foreign objects in the base and whether there is any assembly jamming.

[0070] Alternatively, in embodiments of the present invention, the online monitoring of the active margin can also be achieved by directly acquiring the displacement change of the floating base using high-precision machine vision, or by directly measuring the displacement of the floating base using a high-precision displacement sensor, in order to replace the optical power fluctuation monitoring scheme.

[0071] After the clearance test is passed, the host computer control system controls the locking actuator to continue feeding slowly, using a constant pressure control mode to complete the final locking. The target clamping force is set between 2.5N and 3.5N, and the system collects clamping force data in real time, prohibiting the pressure from exceeding the upper limit. Feeding stops after the target pressure is reached, maintaining a constant clamping force without further locking. After locking, the mechanism is left to stand for 60 seconds to stabilize internal mechanical stress. The entire locking process strictly controls the latch feed speed to prevent instantaneous impact forces from squeezing the thermally compensated floating base. After final locking, the thermally compensated floating base retains a clearance of ≥0.5μm.

[0072] After locking and stabilizing, the temperature control platform is started to execute a short-cycle high and low temperature verification program. The temperature range is set to -20℃ to 95℃, and the single heating and cooling rate is controlled at 3℃ / min to complete one complete heating and cooling cycle. The total test time is controlled within 12 minutes.

[0073] Throughout the entire cycle, the multi-channel optical power detection module continuously collects the coupling loss values ​​of each channel. The system has a preset loss fluctuation threshold of 0.5dB; if the coupling loss fluctuation of any channel exceeds 0.5dB, it is determined that the thermal drift exceeds the standard. If the test is passed, the product directly proceeds to the unloading process; if the test fails, the system automatically unlocks the locking buckle and returns to the step of recalibrating the DFAU position according to the thermal compensation correction coordinate parameters to re-adjust the optical path. Two rework adjustments are allowed; if the product still fails after two adjustments, it is marked as defective and isolated.

[0074] After passing the online high and low temperature verification, the temperature-controlled platform automatically returns to room temperature (25°C) and waits for the substrate temperature to recover to room temperature. The host computer control system then fully releases the latches of the locking actuator, releasing the clamping limit of the DFAU module. The operator removes the assembled DFAU and silicon photonics substrate assembly. The host computer control system automatically stores the compensation coordinates, peak coupling optical power, clamping force data, and high and low temperature loss curves of this assembly, linked to the product's unique barcode, enabling full-process data traceability.

[0075] The DFAU components assembled using the above process have been tested and found to have a single-channel insertion loss of ≤1.2dB, an insertion loss fluctuation of ≤0.3dB across the entire temperature range (-40℃~100℃), and a DFAU that can be repeatedly inserted and removed ≥500 times, fully meeting the mass production requirements of CPO switches.

[0076] The automated coupling and assembly process of the thermally compensated DFAU and silicon photonic microlens array of the present invention can quickly switch between silicon photonic engine products with different numbers of channels (such as 8 channels, 16 channels, 32 channels, and 64 channels) by adjusting the number of channels of the multi-channel optical power detection module and the fine coupling scanning parameters, without the need for large-scale modification of the production line, and has extremely strong technical scalability.

[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. 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. An automated coupling and assembly process for a thermally compensated DFAU and a silicon photonic microlens array, characterized in that, Includes the following steps: The silicon photonics carrier substrate equipped with a silicon photonics PIC chip and microlens array is fixed on a temperature-controlled carrier platform, and the DFAU module pre-assembled with a thermal compensation floating base is placed on a multi-dimensional fine-tuning stage and initially positioned. Optical power data of all optical channels are collected at the first temperature and the second temperature respectively. The optimal coupling coordinates of the optical path at the first temperature and the second temperature are recorded. The thermal expansion offset vector is calculated based on the difference between the optimal coordinates at the two temperatures, and thermal compensation correction coordinate parameters are generated. The position of the DFAU is compensated according to the thermal compensation correction coordinate parameters, and the DFAU and the microlens array are made to reach the target coupling state through the multidimensional motion adjustment of the multidimensional fine-tuning stage. The drive locking actuator pre-locks the DFAU housing with a first clamping force range; In the pre-locked state, a small reciprocating excitation displacement is applied to the thermal compensation floating base, while continuously collecting the optical power values ​​of each channel. The presence of synchronous fluctuations in the optical power is used to determine whether the thermal compensation floating base has a margin of movement. After the movement margin test is qualified, control the locking actuator to continue feeding, and complete the final locking with a second clamping force range greater than the first clamping force range; Start the temperature control platform to perform high and low temperature cycle test. During the entire cycle, continuously collect the coupling loss values ​​of each channel to determine whether the fluctuation of coupling loss of each channel exceeds the preset threshold. After the high and low temperature verification is passed, the DFAU clamping limit is released, the assembled components are removed, and the assembly data is bound to the product identification information for storage.

2. The automated coupling and assembly process of the thermally compensated DFAU and silicon photonic microlens array according to claim 1, characterized in that, The first temperature is 20℃~30℃, and the holding time is 3~8 minutes; the second temperature is 80℃~90℃, and the holding time is 5~12 minutes.

3. The automated coupling and assembly process of the thermally compensated DFAU and silicon photonic microlens array according to claim 1, characterized in that, When collecting optical power data for all optical channels, the following is also included: Point scanning was performed at temperatures ranging from -45℃ to -35℃ to collect optical path offset data under low-temperature conditions and to establish a full-temperature-range compensation model.

4. The automated coupling and assembly process of the thermally compensated DFAU and silicon photonic microlens array according to claim 1, characterized in that, The step of compensating the position of the DFAU according to the thermal compensation correction coordinate parameters and adjusting the multidimensional motion of the multidimensional fine-tuning stage to achieve the target coupling state between the DFAU and the microlens array specifically includes the following steps: The multi-dimensional fine-tuning stage is driven to perform displacement compensation according to the thermal compensation correction coordinate parameters, so that the front guide pin of DFAU is inserted along the guide hole on the side of the silicon photonics substrate to complete the mechanical coarse positioning; wherein, the moving feed speed of the multi-dimensional fine-tuning stage is not higher than 5μm / s; A light signal is input to the input terminal of the silicon photonics chip. When a valid light signal is detected, coarse alignment is determined to be complete. The multi-dimensional fine-tuning stage is driven to perform point scanning in multiple dimensions with sub-micron step sizes, collect the optical power of all channels in real time, search for the global optical power peak point, and determine that the target coupling state is reached when the optimal coupling point is reached. The movement stops and the current optimal coupling coordinates are stored.

5. The automated coupling and assembly process of the thermally compensated DFAU and silicon photonic microlens array according to claim 4, characterized in that, When the average optical power fluctuation of 20 to 40 consecutive sets of sampling data is less than 0.01 dB to 0.03 dB, the optimal coupling point is determined to be reached. The submicron step size is 0.05 μm to 0.2 μm, and the scanning dimensions include five dimensions: X-axis, Y-axis, Z-axis, horizontal deflection, and pitch deflection.

6. The automated coupling and assembly process of the thermally compensated DFAU and silicon photonic microlens array according to claim 1, characterized in that, The first clamping force range is 0.8 N to 1.2 N. After pre-locking, it is left to stand for 20 to 40 seconds to eliminate mechanical contact stress. The second clamping force range is 2.5 N to 3.5 N. The locking adopts a constant pressure control mode. After locking, it is left to stand for 50 to 70 seconds to stabilize the internal mechanical stress.

7. The automated coupling and assembly process of the thermally compensated DFAU and silicon photonic microlens array according to claim 1, characterized in that, The micro reciprocating excitation displacement is 0.3μm to 0.8μm, and it is repeated 2 to 5 times. If the optical power changes continuously with the micro displacement excitation, it is determined that the thermal compensation floating base has a margin of movement. If the optical power remains unchanged under the micro displacement excitation, it is determined that the thermal compensation floating base is locked. At this time, the locking actuator is slightly loosened, and the pre-locking state is readjusted before the micro reciprocating excitation displacement detection is performed again. The number of times the pre-locking state is readjusted is 1 to 3. If it still fails to pass after more than 3 times, an alarm is triggered.

8. The automated coupling and assembly process of the thermally compensated DFAU and silicon photonic microlens array according to claim 7, characterized in that, The thermally compensated floating base retains an active gap of ≥0.5μm after final locking; the DFAU design allows for ≥300 repeated non-destructive insertion and removal cycles.

9. The automated coupling and assembly process of the thermally compensated DFAU and silicon photonic microlens array according to claim 1, characterized in that, The temperature range for the high and low temperature cycling test is -20℃ to 95℃, with heating and cooling rates of 2℃ / min to 5℃ / min, and a single complete cycle duration of ≤15 minutes. The preset threshold is 0.3dB to 0.8dB. If the fluctuation of coupling loss in any channel exceeds the preset threshold, it is determined that the thermal drift exceeds the standard. At this time, the system will automatically unlock and return to the step of re-adjusting the DFAU position based on the thermal compensation correction coordinate parameters.

10. An automated coupling and assembly system for a thermally compensated DFAU and a silicon photonic microlens array, used to implement the assembly process as described in any one of claims 1 to 9, characterized in that, include: Temperature-controlled support platform, used to support and control the temperature of silicon photonics substrate; A multi-dimensional fine-tuning stage with multi-dimensional adjustment capabilities is used to support the DFAU module and realize precise movements in five dimensions: X-axis, Y-axis, Z-axis, horizontal deflection, and pitch deflection. A multi-channel optical power detection module is used to collect the output optical power of each optical channel in real time; Infrared temperature measurement module is used to monitor the temperature of the substrate and coupling area in real time; A locking actuator is used to apply a controllable clamping force to the DFAU housing to achieve graded locking; The host computer control system is used to store the optimal coupling coordinates of the optical path, calculate the thermal expansion offset vector, generate thermal compensation correction coordinate parameters and send them to the motion control system, as well as record and store assembly data.

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