A testing system for micro-ring modulator optical chips

Abstract

This invention relates to a testing system for a micro-ring modulator optical chip, belonging to the field of optical chip testing technology. The system includes: a test sub-board, a control main board, an optical path coupling device, and an output device. The test sub-board receives multi-mode test signals from the control main board to test the optical chip. The test sub-board adjusts the temperature and phase shifter current of the optical chip under test. The output device collects the optical signal output under optical path coupling, and outputs a three-dimensional data lookup table containing the collected optical signal, its temperature, and phase shifter current data. The optical path coupling device couples the optical chip to the test optical signal and monitors the change in optical power in the optical chip's loopback waveguide during coupling to adjust the coupling optical path to the optimal coupling state. This invention improves testing efficiency, supports multi-chip parallel testing and closed-loop optical coupling optimization, achieving rapid resonant wavelength and operating point locking for the optical chip, and efficient batch testing.

Description

Technical Field

[0001] This invention relates to the field of optical chip testing technology, and in particular to a testing system for a micro-ring modulator optical chip. Background Technology

[0002] Silicon photonic chips, as a key technology in modern optical communication and integrated photonics, are widely used in high-speed optical interconnects, data centers, and optical computing. Among various silicon photonic devices, microring modulators have become a research and application hotspot in recent years due to their advantages such as compact structure, low power consumption, adaptability to wavelength division multiplexing scenarios, and high modulation bandwidth. However, compared with traditional Mach-Zehnder modulators, microring modulators, which are essentially resonant cavities, are not only extremely sensitive to temperature and phase shifter current in terms of operating state and stability, but their performance also highly depends on precise temperature and current control. Furthermore, they differ significantly from traditional Mach-Zehnder modulators in terms of monitoring multiple microring devices on a single chip, evaluating the differences in optical performance between microrings, and understanding system impacts. These factors present numerous challenges to the testing phase of optical chips based on microring modulators.

[0003] Existing conventional silicon photonics chip testing systems are primarily designed for Mach-Zehnder modulators, focusing on the chip's static performance, such as dark current testing, Heater phase shifter current aging testing, and chip power-on testing. They lack large-scale testing platforms for the dynamic characteristics of micro-ring modulators, such as temperature drift of the resonant wavelength, modulator operating point adjustment, and multi-parameter collaborative testing and control capabilities. It is worth noting that due to the narrowband and temperature-sensitive characteristics of micro-ring modulators caused by their resonant properties, testing systems must support rapid temperature control, high-precision current injection, dynamic optical coupling calibration, and real-time acquisition of full-spectrum data to achieve systematic modeling and performance evaluation of the dependence of resonant wavelength, temperature, and current.

[0004] Furthermore, existing testing systems typically employ fixed coupling, single-temperature-point, or manual adjustment modes, which cannot achieve multi-chip parallel processing, full-temperature-range scanning, or closed-loop optical coupling optimization. This results in low testing efficiency and poor repeatability, making it difficult to support the high-precision, high-throughput testing requirements of mass production scenarios. In particular, regarding resonant wavelength and operating point locking control, traditional PID algorithms have long response times and limited adjustment accuracy, making it difficult to meet the stringent requirements for resonant wavelength stability in high-speed communication scenarios. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a test system for micro-ring modulator optical chips, which solves the technical problems that the existing test systems cannot achieve high-precision, high-efficiency, closed-loop collaborative testing of the resonant wavelength, temperature, and current dependence of micro-ring modulator optical chips, and are difficult to complete fast wavelength locking and performance evaluation in multi-chip parallel testing scenarios.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0009] This invention provides a testing system for micro-ring modulator optical chips, comprising: a test sub-board carrying multiple optical chips under test, a control main board, an optical path coupling device, and an output device;

[0010] The test subboard and the control motherboard are detachably connected, and the test subboard receives multi-mode test signals from the control motherboard to test each optical chip under test, including temperature test signals, MPD current acquisition signals and phase shifter current test signals.

[0011] The test sub-board adjusts the temperature and phase shifter current of the optical chip under test based on the temperature test signal and the phase shifter current test signal. The output device collects the optical signal output by each optical chip under test in the optical path coupling state with the preset test optical signal. The collected optical signal, the temperature data and the phase shifter current data of the optical signal are formed into a three-dimensional data lookup table and output.

[0012] For each optical chip under test, the optical path coupling device is used to optically couple the optical waveguide of the optical chip under test with the test optical signal, and monitor the change in optical power of the loop waveguide of the optical chip under test during the coupling process in order to adjust the coupling pose and obtain the optimal optical path coupling state between the optical chip under test and the test optical signal.

[0013] Optionally, the optical path coupling device includes: a tunable optical path, an optical fiber array, an adjustable alignment mechanism, and a loopback power adjustment unit;

[0014] The tunable optical path is used to output test optical signals;

[0015] The fiber optic array is connected to the end of the tunable optical path and is used to optically couple the test optical signal to the optical waveguide of the optical chip under test.

[0016] The adjustable alignment mechanism is used to adjust the coupling pose between the fiber array and the optical chip under test;

[0017] The loopback optical power adjustment unit monitors the change in optical power of the loopback waveguide of the optical chip under test during coupling and dynamically adjusts the adjustable alignment mechanism to optimize the coupling pose between the fiber array and the optical chip under test, thereby obtaining the optimal optical path coupling state between the optical chip under test and the test optical signal.

[0018] Optionally, the tunable optical path includes: a light source, an optical isolator, a tunable optical attenuator, a polarization controller, and an optical switch;

[0019] The light source is a DFB laser, which is used to provide the input seed light source for the operation of the micro-ring modulator;

[0020] An optical isolator is placed at the output end of the light source to suppress the interference of reflected light on the input seed light source;

[0021] An adjustable optical attenuator is set at the output end of the optical isolator to finely adjust the optical power of the input seed light source and output the optical signal of the target optical power.

[0022] The polarization controller is set at the output end of the adjustable optical attenuator to control the polarization state of the output optical signal of the adjustable optical attenuator and output the test optical signal.

[0023] An optical switch is located at the output of the polarization controller and is used to switch and distribute the test optical signal to different fiber arrays so as to realize the sequential testing of multiple optical chips under test.

[0024] Among them, the optical switch is a 1×N mechanical or electro-optical optical switch, where N is the number of test platforms and N≥2. The test platforms are set on the test sub-board and are used to carry the optical chip under test.

[0025] Optionally, the fiber array includes: a polarization-maintaining fiber input port, a transmitting fiber, a loopback fiber, and a receiving fiber;

[0026] The polarization-maintaining fiber input port is used to receive test optical signals;

[0027] The transmitting optical fiber is used to couple the test optical signal to the input optical port of the optical chip under test;

[0028] The loopback fiber is connected to the loopback port of the optical chip under test, and is used to receive and feed back the loopback optical signal to the loopback optical power adjustment unit.

[0029] The receiving optical fiber is connected to the output optical port of the optical chip under test, and is used to receive the test optical signal modulated by the optical chip under test and transmit it to the output device.

[0030] The transmitting fiber, loopback fiber, and receiving fiber are arranged in the fiber array according to preset positions and quantities, and are aligned with the waveguide structure of the optical chip under test.

[0031] Optionally, the adjustable alignment mechanism includes: a horizontal adjustment module, a vertical adjustment module, and an angle adjustment module;

[0032] The horizontal adjustment module is used to drive the fiber array to perform axial displacement along the X and Y axes to match the optical port position of the optical chip under test;

[0033] The vertical adjustment module is used to drive the fiber array to move vertically up and down along the Z-axis to adjust the coupling distance between the fiber end face and the waveguide end face of the optical chip under test.

[0034] The angle adjustment module is used to drive the fiber array to adjust its pitch and deflection, so as to optimize the optical axis alignment angle between the fiber array and the optical waveguide of the optical chip under test.

[0035] The horizontal adjustment module, vertical adjustment module, and angle adjustment module are all driven by motor drivers and receive feedback control signals from the loop back light power adjustment unit to achieve closed-loop dynamic adjustment of the coupled pose.

[0036] Optionally, the loopback optical power adjustment unit includes: an optical power meter array, a signal processing module, and a control feedback module;

[0037] The optical power meter array is connected to the loopback fiber in the optical fiber array to monitor the optical power signals input and output to the loopback fiber in real time.

[0038] The signal processing module is connected to the optical power meter array to compare the change in loopback optical power under different coupling poses, determine the coupling adjustment direction to maximize the loopback optical power based on the change in loopback optical power, and calculate the optical power change of loopback optical power with adjustment in real time during coupling, and output a command signal to stop the coupling pose adjustment when the preset optical power threshold is reached.

[0039] The control feedback module is connected to the signal processing module and the adjustable alignment mechanism respectively. It is used to control the adjustable alignment mechanism to perform initial coupling pose adjustment according to the position information of the optical chip under test, and to generate control signals and drive the adjustable alignment mechanism to perform dynamic fine adjustment of coupling pose according to the adjustment instructions output by the signal processing module.

[0040] The number of channels in the optical power meter array is the same as the number of test platforms, and each channel corresponds to one test platform, supporting independent monitoring and feedback control of the loopback optical power of each optical chip under test.

[0041] Optionally, the test platform includes: a heat sink base, a temperature sensor, and a temperature controller;

[0042] The heat sink base is used to support and fix the optical chip under test;

[0043] The temperature sensor is set on the heat sink base and makes thermal contact with the optical chip under test. It is used to monitor the operating temperature of the optical chip under test in real time and feed the temperature signal back to the temperature controller.

[0044] The temperature controller is connected to the temperature sensor and the control motherboard respectively. It is used to actively heat or cool the heat sink base according to the temperature test signal, and to maintain the temperature of the heat sink base based on the feedback temperature signal from the temperature sensor.

[0045] Optionally, the output device includes: a spectrometer, a data acquisition card, and a spectral processing unit;

[0046] The spectrometer is connected to the receiving fiber in the fiber array to acquire the spectral signal output by the optical chip under test in real time.

[0047] The data acquisition card includes a phase shifter current scanning matrix and a temperature scanning matrix, which are used to synchronously acquire the phase shifter current value and temperature value corresponding to each test optical chip, and perform time-series pairing with the spectral signal.

[0048] The spectral processing unit is connected to the spectrometer and the data acquisition card respectively, and is used to perform real-time analysis of spectral data, extract resonant wavelength data, and construct a three-dimensional data lookup table containing the correspondence between resonant wavelength, temperature and phase shifter current based on the combination of temperature and phase shifter current.

[0049] Among them, the three-dimensional data lookup table supports querying the resonant wavelength corresponding to the optical chip by using temperature and phase shifter current as indexes, or querying the control parameters of the optical chip by using the resonant wavelength as indexes.

[0050] Optionally, the control motherboard includes: a controller, an analog front-end chip, status indicator lights, a communication interface, and a power interface;

[0051] The number of analog front-end chips is configured to be several, and all of them are connected to the controller. They are used to output multi-mode test signals, including temperature test signals, MPD current acquisition signals and phase shifter current test signals, based on the controller's output of optical chip test commands.

[0052] The status indicator light is connected to the controller and is used to indicate the system's operating status and abnormal alarms;

[0053] The communication interface connects to the controller to enable data interaction and command transmission with a pre-set host computer.

[0054] The power interface is used to connect to an external power source to provide a stable power supply for the control motherboard, test daughterboard, optical coupling device, and output device.

[0055] Optionally, the test sub-board includes a metal protective cover that covers the chip under test to prevent external physical impacts, dust contamination, and light interference.

[0056] (III) Beneficial Effects

[0057] The beneficial effects of this invention are as follows: The testing system for micro-ring modulator optical chips of this invention, by adopting a multi-module collaborative testing architecture consisting of a test sub-board, a control main board, an optical path coupling device, and an output device, realizes automatic acquisition of full-spectrum data and construction of a three-dimensional data lookup table for batches of micro-ring modulator optical chips under multiple temperature and current parameter combinations. Compared with the prior art, it significantly improves testing accuracy and efficiency, supports multi-chip parallel testing and closed-loop optical coupling optimization, and achieves the technical effects of rapid resonant wavelength locking, high stability testing, and batch testing.

[0058] Furthermore, the optical path coupling device of the present invention uses a loopback optical power monitoring and feedback control mechanism to monitor the change in optical power of the loopback waveguide of the optical chip under test during coupling and dynamically adjust the coupling pose to optimize the optical path coupling state. This effectively solves the problems of low optical coupling efficiency and poor test repeatability caused by alignment deviation in traditional manual or fixed coupling methods, and significantly improves the stability of optical signal injection and the reliability of test results. Attached Figure Description

[0059] Figure 1 This is a schematic diagram of the composition of a control motherboard provided in an embodiment of the present invention;

[0060] Figure 2 This is a schematic diagram illustrating the composition of a test sub-board, an optical path coupling device, and an output device according to an embodiment of the present invention.

[0061] Figure 3 A schematic diagram of the composition of a test platform provided in an embodiment of the present invention;

[0062] Figure 4 This is a schematic diagram of the composition of an optical fiber array provided in an embodiment of the present invention;

[0063] Figure 5 This is a schematic diagram of the adjustable alignment mechanism provided in an embodiment of the present invention;

[0064] Figure 6 This is a diagram illustrating a three-dimensional data lookup table provided in an embodiment of the present invention.

[0065] Figure 7 This is a schematic diagram illustrating the working principle of a micro-ring modulator optical chip provided in an embodiment of the present invention. Detailed Implementation

[0066] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0067] refer to Figures 1 to 6As shown in the figure, a test system for a micro-ring modulator optical chip proposed in this embodiment of the invention includes: a test sub-board carrying multiple optical chips under test, a control main board, an optical path coupling device, and an output device; the test sub-board and the control main board are detachably connected, and the test sub-board receives multi-mode test signals from the control main board to test each optical chip under test, including temperature test signals, MPD current acquisition signals, and phase shifter current test signals; the test sub-board adjusts the temperature and phase shifter current of the optical chip under test based on the temperature test signals and phase shifter current test signals, and the output device acquires the optical signal output by each optical chip under test in an optical path coupling state with a preset test optical signal, and outputs a three-dimensional data lookup table formed by the acquired optical signal, the temperature data of the optical signal, and the phase shifter current data; for each optical chip under test, the optical path coupling device is used to optically couple the optical waveguide of the optical chip under test with the test optical signal, and monitor the change in optical power of the loopback waveguide of the optical chip under test during the coupling process to adjust the coupling posture and obtain the optimal optical path coupling state between the optical chip under test and the test optical signal.

[0068] This embodiment employs a multi-module collaborative testing architecture comprising a test sub-board, a control mainboard, an optical path coupling device, and an output device. This architecture enables automatic acquisition of full-spectrum data and construction of a three-dimensional data lookup table for batches of micro-ring modulator optical chips under various temperature and current parameter combinations. Compared to existing technologies, it significantly improves testing accuracy and efficiency, supports parallel testing of multiple chips and closed-loop optical coupling optimization, achieving rapid resonant wavelength locking, high stability testing, and batch testing capabilities. Furthermore, the optical path coupling device in this embodiment utilizes a loopback optical power monitoring and feedback control mechanism. By monitoring the changes in optical power in the loopback waveguide of the optical chip under test during coupling, it dynamically adjusts the coupling pose to optimize the optical path coupling state. This effectively solves the problems of low optical coupling efficiency and poor test repeatability caused by alignment deviations in traditional manual or fixed coupling methods, significantly improving the stability of optical signal injection and the reliability of test results.

[0069] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0070] First, refer to Figure 1As shown, the control motherboard includes: a controller, analog front-end chips (AFE1, AFE2, ..., AFEn), status indicator lights, a communication interface, and a power interface. The number of analog front-end chips can be flexibly configured according to the actual test channel requirements and is connected to the controller. It is used to generate multi-mode test signals, including temperature test signals, MPD (monitoring photodiode) current acquisition signals, and phase shifter current test signals, based on the controller's output optical chip test commands. This enables comprehensive performance excitation and measurement of the micro-ring modulator optical chip. The status indicator lights are connected to the controller to indicate the system's operating status (e.g., standby, testing, completed) and abnormal alarms (e.g., overcurrent, communication interruption, test timeout). The communication interface is connected to the controller to enable data interaction and command transmission with a preset host computer (mainly a remote control platform and data server), forming a remotely controllable test link. The power interface is used to connect an external power supply to provide stable power to the control motherboard, test daughterboard, optical coupling device, and output device.

[0071] In this embodiment, the host computer first sends the test task and parameter configuration of the micro-ring modulator optical chip to the controller via the communication interface. Based on the number of optical chips under test and the test type, the controller schedules the corresponding analog front-end chip to output multi-mode test signals to the test sub-board, thereby driving and acquiring the optical chip's response. The test content includes: MPD dark current, Heater current aging test, chip power-on test, and optical waveguide performance evaluation. During the test, the controller collects test data and uses status indicator lights to represent the system's operating status and trigger alarms. During the test, the controller collects and preprocesses test data in real time, providing feedback on the system's operating status through status indicator lights and triggering alarms when abnormalities occur. All test data can be transmitted back to the host computer via the communication interface for further analysis, storage, and report generation.

[0072] Next, refer to Figures 1 to 3 As shown, the test sub-board is detachably connected to the control motherboard via connectors (such as high-density board-to-board connectors). It includes multiple independent test platforms for carrying the optical chips under test. Each test platform carries one optical chip under test and forms a one-to-one communication and control link with the corresponding analog front-end chip on the control motherboard. Each test platform receives multimodal test signals from the control motherboard and performs phase shifter current control and precision temperature regulation on the optical chip under test.

[0073] In this embodiment, reference Figure 3As shown, the test platform includes a heat sink base, a temperature sensor, and a temperature controller. The heat sink base is used to support and fix the optical chip under test (OST). It is preferably made of a tungsten-copper alloy with high thermal conductivity and low coefficient of thermal expansion to provide rapid thermal response and a stable temperature environment. The temperature sensor is mounted on the heat sink base and in thermal contact with the OST. It is used to monitor the operating temperature of the OST in real time and feed the temperature signal back to the temperature controller. Preferably, the temperature sensor is a high-precision negative temperature coefficient thermistor. The temperature controller is connected to both the temperature sensor and the analog front-end chip. It is used to actively heat or cool the heat sink base according to the temperature test signal to adjust the operating temperature of the OST. It also performs constant temperature control of the heat sink base based on the feedback temperature signal from the temperature sensor. For scenarios requiring testing temperature gradient sensitivity, the temperature controller can support zoned temperature control of the heat sink base.

[0074] In this embodiment, to ensure the reliability of the testing process and the consistency of the results, the test sub-board is also equipped with a metal protective cover. After the optical chip under test is aligned and coupled, the metal protective cover can tightly cover the chip and the coupling area to prevent external physical collisions, dust pollution and light interference.

[0075] Then, refer to Figure 2 As shown, the optical path coupling device includes a tunable optical path, an optical fiber array, an adjustable alignment mechanism, and a loopback optical power adjustment unit. The tunable optical path outputs a test optical signal, the wavelength, power, and polarization state of which are controllable. The optical fiber array is connected to the end of the tunable optical path and is used to optically couple the test optical signal to the optical waveguide of the optical chip under test (DUT). The adjustable alignment mechanism adjusts the coupling pose between the optical fiber array and the DUT. The loopback optical power adjustment unit monitors the change in optical power of the DUT's loopback waveguide during coupling and dynamically feeds back to the adjustable alignment mechanism to optimize the coupling pose between the optical fiber array and the DUT, obtaining the optimal optical path coupling state between the DUT and the test optical signal. By introducing real-time feedback and control of the loopback optical power, the optical path coupling device upgrades the traditional experience-based static alignment to adaptive dynamic optimization, significantly improving coupling efficiency and test consistency, and enhancing the system's robustness to external disturbances such as optical chip process deviations and thermal drift. Meanwhile, the modular optical path and multi-channel switching capability support rapid chip replacement and batch testing, providing an efficient and accurate automated solution for the research and development verification and production testing of optical chips.

[0076] In this embodiment, the optical path coupling device operates as follows: First, the test optical signal generated by the tunable optical path is sent to the optical chip under test (DUT) through the transmitting fiber in the fiber array. Then, the loopback waveguide inside the DUT sends a portion of the optical signal back to the loopback optical power adjustment unit through the loopback fiber. Finally, the loopback optical power adjustment unit analyzes the change in loopback optical power, generates control commands, and drives the adjustable alignment mechanism to dynamically adjust the relative position and angle between the fiber array and the DUT until the loopback optical power is maximized, indicating that the optimal coupling state has been reached.

[0077] Further, refer to Figure 2 As shown, the tunable optical path includes: a light source, an optical isolator, a tunable optical attenuator, a polarization controller, and an optical switch. The light source is a tunable high-power DFB laser, used to provide a tunable wavelength input seed source for the micro-ring modulator, capable of covering multiple characteristic wavelength points within the optical chip's operating band, meeting the full-spectrum testing requirements for its wavelength-dependent performance (such as center wavelength, bandwidth, and wavelength-dependent loss). The optical isolator is located at the output end of the light source to suppress interference from back-reflected light on the input seed source. A large numerical aperture (NA) optical isolator is preferred, as it can accommodate a larger divergence angle light signal, improving coupling tolerance and overall coupling efficiency with subsequent single-mode fibers, while further reducing the system noise floor introduced by end-face reflections. The tunable optical attenuator is located at the output end of the optical isolator, used to adjust the optical power of the input seed source and output a target optical power signal, simulating various input optical power conditions that may be encountered in actual system applications, and testing key performance indicators such as the linear operating range, saturated input / output power, and damage threshold of the optical chip. A polarization controller is located at the output of the tunable optical attenuator to control the polarization state of the output optical signal. By systematically changing the input polarization state, the polarization characteristics of the optical chip, such as polarization-dependent loss (PDL), polarization mode dispersion (PMD), and polarization extinction ratio (PER), can be comprehensively evaluated, providing crucial data for micro-ring modulator design. An optical switch is located at the output of the polarization controller to switch and distribute the test optical signal to different fiber arrays, enabling parallel testing of multiple optical chips under test. This significantly improves the parallel processing capability and test throughput of the entire testing system while reducing the cost of testing a single chip. The optical switch is a 1×N mechanical or electro-optic switch, where N is the number of test platforms, and N≥2. The test platforms are located on the test sub-board and are used to support the optical chips under test.

[0078] Further, refer to Figure 4As shown, the fiber optic array includes: a polarization-maintaining fiber input port, a transmitting fiber, a loopback fiber, and a receiving fiber. The polarization-maintaining fiber input port is used to receive the test optical signal. The transmitting fiber is used to couple the test optical signal to the input port of the optical chip under test (ODT). The loopback fiber connects to the loopback port of the ODT and is used to receive and feed back the loopback optical signal to the loopback optical power adjustment unit. The receiving fiber connects to the output port of the ODT and is used to receive the test optical signal modulated by the ODT and transmit it to the output device. The transmitting fiber, loopback fiber, and receiving fiber are arranged in the fiber optic array according to preset positions and quantities, and are aligned with the waveguide structure of the ODT.

[0079] Further, refer to Figure 5 As shown, the adjustable alignment mechanism includes a horizontal adjustment module, a vertical adjustment module, and an angle adjustment module. The horizontal adjustment module drives the fiber array to perform axial displacement along the X and Y axes to match the optical port position of the optical chip under test. The vertical adjustment module drives the fiber array to move vertically up and down along the Z axis to adjust the coupling distance between the fiber end face and the optical waveguide end face of the optical chip under test. The angle adjustment module drives the fiber array to perform pitch and deflection adjustments to optimize the optical axis alignment angle between the fiber array and the optical waveguide of the optical chip under test. All three modules—horizontal, vertical, and angle—are driven by high-precision motor drivers and receive feedback control signals from the loopback optical power adjustment unit, achieving sub-micron and milliradian-level closed-loop dynamic adjustment.

[0080] Further, refer to Figure 2 As shown, the loopback optical power adjustment unit includes an optical power meter array, a signal processing module, and a control feedback module. The optical power meter array is connected to the loopback fiber in the fiber array to monitor the optical power signals input and output to the loopback fiber in real time. The signal processing module is connected to the optical power meter array and is used to compare the changes in loopback optical power under different coupling poses, determine the coupling adjustment direction to maximize the loopback optical power based on the changes in loopback optical power, and calculate the changes in loopback optical power with adjustment in real time during coupling, outputting a command signal to stop coupling pose adjustment when a preset optical power threshold is reached. The control feedback module is connected to both the signal processing module and the adjustable alignment mechanism. Based on the position information of the optical chip under test, it controls the adjustable alignment mechanism to perform initial coupling pose adjustment, and then generates a control signal based on the adjustment command output by the signal processing module to drive the adjustable alignment mechanism to perform dynamic fine-tuning of the coupling pose. This process significantly reduces the need for manual intervention and improves the repeatability and reliability of coupling. The number of channels in the optical power meter array is the same as the number of test platforms, and each channel corresponds to one test platform, supporting independent monitoring and feedback control of the loopback optical power of each optical chip under test.

[0081] Finally, the output device collects the output spectra of each optical chip under test under different combinations of temperature and phase shifter current, and constructs a three-dimensional data lookup table containing the correspondence between resonant wavelength, temperature, and phase shifter current. The three-dimensional data lookup table can be parameterized. Figure 6 As shown, based on this, the main controller of the micro-ring modulator can quickly look up the phase shifter current at the corresponding operating temperature using a three-dimensional data lookup table obtained from the test, thereby enabling the resonant wavelength of the micro-ring modulator optical chip to be quickly locked and kept stable. (Reference) Figure 2 As shown, the output device includes: a spectrometer, a data acquisition card, and a spectral processing unit; the spectrometer is connected to the receiving fiber in the fiber array for real-time acquisition of the spectral signal output by the optical chip under test; the data acquisition card includes a phase shifter current scanning matrix and a temperature scanning matrix for synchronously acquiring the phase shifter current and temperature values ​​corresponding to each tested optical chip and performing time-series pairing with the spectral signal; the spectral processing unit is connected to the spectrometer and the data acquisition card respectively for real-time analysis of the spectral data, extraction of resonant wavelength data, and construction of a three-dimensional data lookup table containing the correspondence between resonant wavelength, temperature, and phase shifter current based on the combination of temperature and phase shifter current; wherein, the three-dimensional data lookup table supports querying the resonant wavelength corresponding to the optical chip by using temperature and phase shifter current as indexes, or querying the control parameters of the optical chip by using the resonant wavelength as an index.

[0082] In one specific embodiment, given the unique characteristics of micro-ring modulator (MRM) optical chips, accurate testing of their waveguide performance is crucial. (Reference) Figure 7 As shown, the micro-ring modulator operates based on the resonance effect, and its resonant wavelength is extremely sensitive to minute changes in operating temperature and phase shifter injection current. Therefore, to ensure the device's performance and stability in practical applications, systematic parameter calibration and performance testing are essential. Key performance tests include: test data on the effect of temperature on the resonant wavelength of the micro-ring modulator, and test data on the effect of the phase shifter on the resonant wavelength of the micro-ring modulator. The specific test steps are as follows:

[0083] The first step involves the controller sending a precise temperature setpoint command to the temperature controller on the designated test platform via the analog front-end chip. The temperature controller then drives the thermoelectric cooler, enabling the heat sink base and the micro-ring modulator optical chip fixed on it to quickly reach the target temperature. Closed-loop constant temperature control is then implemented using feedback from a high-precision temperature sensor to ensure the chip is in a thermally stable state before the test begins, requiring temperature fluctuations to be less than ±0.02°C.

[0084] The second step involves, under stable temperature conditions, the controller outputting a sequence of programmable current test signals to the phase shifter electrodes of the micro-ring modulator under test via an analog front-end chip. For each injected phase shifter current value, the output spectrum is acquired and recorded in real time through a coupled optical path and an external spectral analyzer or high-precision wavelength meter, accurately identifying and recording the center wavelength of the micro-ring resonance valley at that moment.

[0085] The third step involves repeating steps one and two to form a nested loop test. Within a set temperature test range (e.g., 0°C to 70°C), the chip operating temperature is gradually changed according to a preset temperature step size (e.g., 0.1°C). At each temperature point, a complete phase shifter current scan and corresponding resonant wavelength data acquisition are performed. This process is automated until the entire two-dimensional parameter plane of temperature and current is traversed.

[0086] The fourth step involves post-processing all raw test data by the spectral processing unit. First, all measured resonant wavelengths are aligned and grouped according to a preset wavelength accuracy (e.g., 0.02 nm). Then, for each target temperature point (in 0.1°C increments) and each target resonant wavelength point (in 0.02 nm increments), the specific phase shifter current value required to achieve the target resonant wavelength is selected from all measured temperature and current curves. Finally, the selected and calculated data is organized into a structured three-dimensional data lookup table, such as... Figure 6 As shown, the operating wavelengths 1 / 2 / 3 / 4 meet the wavelength division multiplexing grid standard. The core data relationship of this lookup table is: for any given target operating temperature and target resonant wavelength, the required phase shifter control current can be directly obtained by looking up the table.

[0087] Fifth, after the test is completed, the controller uploads the generated complete 3D data lookup table and necessary metadata (such as chip ID, test time, test conditions, etc.) to the data server for data storage via the communication interface.

[0088] In summary, the micro-ring modulator optical chip testing system proposed in this invention, through the high integration and collaborative operation of the test sub-board, control mainboard, optical path coupling device, and output device, constructs an automated, high-precision, and batch-processable full-parameter testing system. This system not only achieves automatic acquisition of full-spectrum data of the micro-ring modulator optical chip under multiple temperature and current combinations, but also dynamically optimizes the optical path coupling state through a closed-loop feedback mechanism, ensuring the stability of the testing process and the repeatability of the results. The resulting three-dimensional data lookup table provides crucial data support for the rapid resonant wavelength locking and stable operation of the micro-ring modulator in practical applications, significantly improving device development efficiency, production testing throughput, and the performance consistency of the final product. This system has a flexible architecture and strong scalability, making it suitable for the research, verification, and large-scale testing of various high-performance micro-ring modulator optical chips in fields such as optical communication and optical computing.

[0089] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0090] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, as well as combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions.

[0091] It should be noted that in the description of this invention, the word "a" or "an" preceding a component does not exclude the existence of multiple such components. This invention can be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. The use of terms such as first, second, third, etc., is merely for convenience and does not indicate any order. These terms can be understood as part of the component names.

[0092] Furthermore, it should be noted that in the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0093] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning of the basic inventive concept, can make other changes and modifications to these embodiments.

[0094] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from the spirit and scope of the invention.

Claims

1. A testing system for a micro-ring modulator optical chip, characterized in that, include: The test sub-board, control motherboard, optical path coupling device, and output device carry multiple optical chips under test; The test subboard and the control motherboard are detachably connected, and the test subboard receives multi-mode test signals from the control motherboard to test each optical chip under test, including temperature test signals, MPD current acquisition signals and phase shifter current test signals. The test sub-board adjusts the temperature and phase shifter current of the optical chip under test based on the temperature test signal and the phase shifter current test signal, respectively. The output device includes a data acquisition card and a spectral processing unit. The data acquisition card is used to synchronously acquire the phase shifter current and temperature values ​​corresponding to each test optical chip, and to perform time-series pairing with the spectral signals output by the optical chip under test in the optical path coupling state. The spectral processing unit is used to analyze the spectral data, extract the resonant wavelength data, and construct a three-dimensional data lookup table containing the correspondence between resonant wavelength, temperature and phase shifter current based on the combination of temperature and phase shifter current. The three-dimensional data lookup table supports querying the resonant wavelength corresponding to the optical chip by using temperature and phase shifter current as indexes, or querying the control parameters of the optical chip by using the resonant wavelength as an index. For each optical chip under test, the optical path coupling device is used to optically couple the optical waveguide of the optical chip under test with the test optical signal, and monitor the change in optical power of the loop waveguide of the optical chip under test during the coupling process in order to adjust the coupling pose and obtain the optimal optical path coupling state between the optical chip under test and the test optical signal.

2. A test system for a micro-ring modulator optical chip as claimed in claim 1, wherein, The optical path coupling device includes: a tunable optical path, an optical fiber array, an adjustable alignment mechanism, and a loopback power adjustment unit; The tunable optical path is used to output test optical signals; The fiber optic array is connected to the end of the tunable optical path and is used to optically couple the test optical signal to the optical waveguide of the optical chip under test. The adjustable alignment mechanism is used to adjust the coupling pose between the fiber array and the optical chip under test; The loopback optical power adjustment unit monitors the change in optical power of the loopback waveguide of the optical chip under test during coupling and dynamically adjusts the adjustable alignment mechanism to optimize the coupling pose between the fiber array and the optical chip under test, thereby obtaining the optimal optical path coupling state between the optical chip under test and the test optical signal.

3. A test system for a micro-ring modulator optical chip as claimed in claim 2, wherein, A tunable optical path includes: a light source, an optical isolator, a tunable optical attenuator, a polarization controller, and an optical switch; The light source is a DFB laser, which is used to provide the input seed light source for the operation of the micro-ring modulator; An optical isolator is placed at the output end of the light source to suppress the interference of reflected light on the input seed light source; An adjustable optical attenuator is set at the output end of the optical isolator to adjust the optical power of the input seed light source and the optical signal of the output target optical power; The polarization controller is set at the output end of the adjustable optical attenuator to control the polarization state of the output optical signal of the adjustable optical attenuator and output the test optical signal. An optical switch is located at the output of the polarization controller to switch and distribute the test optical signal to different fiber arrays, so as to realize the parallel testing of multiple optical chips under test. Among them, the optical switch is a 1×N mechanical or electro-optical optical switch, where N is the number of test platforms and N≥2. The test platforms are set on the test sub-board and are used to carry the optical chip under test.

4. The testing system for a micro-ring modulator optical chip as described in claim 2, characterized in that, The fiber array includes: polarization-maintaining fiber input port, transmitting fiber, loopback fiber, and receiving fiber; The polarization-maintaining fiber input port is used to receive test optical signals; The transmitting optical fiber is used to couple the test optical signal to the input optical port of the optical chip under test; The loopback fiber is connected to the loopback port of the optical chip under test, and is used to receive and feed back the loopback optical signal to the loopback optical power adjustment unit. The receiving optical fiber is connected to the output optical port of the optical chip under test, and is used to receive the test optical signal modulated by the optical chip under test and transmit it to the output device. The transmitting fiber, loopback fiber, and receiving fiber are arranged in the fiber array according to preset positions and quantities, and are aligned with the waveguide structure of the optical chip under test.

5. The testing system for a micro-ring modulator optical chip as described in claim 2, characterized in that, The adjustable alignment mechanism includes: a horizontal adjustment module, a vertical adjustment module, and an angle adjustment module; The horizontal adjustment module is used to drive the fiber array to perform axial displacement along the X and Y axes to match the optical port position of the optical chip under test; The vertical adjustment module is used to drive the fiber array to move vertically up and down along the Z-axis to adjust the coupling distance between the fiber end face and the waveguide end face of the optical chip under test. The angle adjustment module is used to drive the fiber array to adjust its pitch and deflection, so as to optimize the optical axis alignment angle between the fiber array and the optical waveguide of the optical chip under test. The horizontal adjustment module, vertical adjustment module, and angle adjustment module are all driven by motor drivers and receive feedback control signals from the loop back light power adjustment unit to achieve closed-loop dynamic adjustment of the coupled pose.

6. The testing system for a micro-ring modulator optical chip as described in claim 2, characterized in that, The loopback optical power adjustment unit includes: an optical power meter array, a signal processing module, and a control feedback module; The optical power meter array is connected to the loopback fiber in the optical fiber array to monitor the optical power signals input and output to the loopback fiber in real time. The signal processing module is connected to the optical power meter array to compare the change in loopback optical power under different coupling poses, determine the coupling adjustment direction to maximize the loopback optical power based on the change in loopback optical power, and calculate the optical power change of loopback optical power with adjustment in real time during coupling, and output a command signal to stop the coupling pose adjustment when the preset optical power threshold is reached. The control feedback module is connected to the signal processing module and the adjustable alignment mechanism respectively. It is used to control the adjustable alignment mechanism to perform initial coupling pose adjustment according to the position information of the optical chip under test, and to generate control signals and drive the adjustable alignment mechanism to perform dynamic fine adjustment of coupling pose according to the adjustment instructions output by the signal processing module. The number of channels in the optical power meter array is the same as the number of test platforms, and each channel corresponds to one test platform, supporting independent monitoring and feedback control of the loopback optical power of each optical chip under test.

7. The testing system for a micro-ring modulator optical chip as described in claim 2, characterized in that, The testing platform includes: a heat sink base, a temperature sensor, and a temperature controller; The heat sink base is used to support and fix the optical chip under test; The temperature sensor is set on the heat sink base and makes thermal contact with the optical chip under test. It is used to monitor the operating temperature of the optical chip under test in real time and feed the temperature signal back to the temperature controller. The temperature controller is connected to the temperature sensor and the control motherboard respectively. It is used to actively heat or cool the heat sink base according to the temperature test signal, and to maintain the temperature of the heat sink base based on the feedback temperature signal from the temperature sensor.

8. The testing system for a micro-ring modulator optical chip as described in claim 2, characterized in that, Output devices include: a spectrometer; The spectrometer is connected to the receiving fiber in the fiber array to acquire the spectral signal output by the optical chip under test in real time.

9. The testing system for a micro-ring modulator optical chip as described in claim 1, characterized in that, The control board includes: a controller, an analog front-end chip, status indicator lights, a communication interface, and a power interface; The number of analog front-end chips is configured to be several, and all of them are connected to the controller. They are used to output multi-mode test signals, including temperature test signals, MPD current acquisition signals and phase shifter current test signals, based on the controller's output of optical chip test commands. The status indicator light is connected to the controller and is used to indicate the system's operating status and abnormal alarms; The communication interface connects to the controller to enable data interaction and command transmission with a pre-set host computer. The power interface is used to connect to an external power source to provide a stable power supply for the control motherboard, test daughterboard, optical coupling device, and output device.

10. The testing system for a micro-ring modulator optical chip as described in claim 1, characterized in that, The test sub-board includes a metal protective cover, which covers the chip under test to prevent external physical impacts, dust contamination, and light interference.

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