Detection circuit and method for an optical phased array opa chip

Abstract

The application provides a detection circuit and method of an optical phased array (OPA) chip. The circuit comprises a laser assembly, a first electrode, a second electrode and a signal processing unit; the first electrode and the second electrode are respectively arranged on the OPA chip, and the second electrode is electrically connected to the signal processing unit; the laser assembly is used for emitting laser beams with different optical powers to the OPA chip; the first electrode is used for transmitting an alternating voltage signal into a silicon waveguide of the OPA chip; the second electrode is used for transmitting an alternating current signal to the signal processing unit; the signal processing unit is used for signal processing on the alternating current signal and outputting a processing result; when it is detected that the processing result indicates that the conductivity of the silicon waveguide changes with the change of the optical power of the laser beam, it is determined that the OPA chip can work normally. Thus, nondestructive detection of the OPA chip is realized, the layout design inside the OPA chip is not damaged, the performance of the OPA chip is ensured, and the performance of a laser radar system containing the OPA chip is ensured.

Description

Technical Field

[0001] This application relates to the field of lidar technology, and in particular to a detection circuit and method for an optical phase array (OPA) chip. Background Technology

[0002] LiDAR systems enable laser ranging and are applied in numerous fields, including machine vision, advanced driver-assistance systems (ADAS), video games, healthcare, leisure and entertainment, and smart homes. In LiDAR systems, OPA chips have become a crucial component due to their high integration and low cost. Therefore, the performance of the OPA chip has a significant impact on the overall performance of the LiDAR system.

[0003] Currently, various related technologies can be used to test OPA chips.

[0004] In related technology 1, it is necessary to change the internal layout design of the OPA chip, adding a directional coupler or a wavelength division multiplexer to separate a portion of the laser light to measure the optical power of each stage within the OPA chip. It is evident that related technology 1 reduces the energy of the laser emitted into the OPA chip, affecting the output optical power of the OPA chip and constraining the propagation path of the laser within the OPA chip.

[0005] In related technology 2, the internal layout design of the OPA chip needs to be modified by adding a grating coupler to divert a portion of the laser light to measure the output power of the antenna in the OPA chip. It is evident that in related technology 2, a portion of the laser light is output via the grating coupler instead of being emitted through the antenna, reducing the number of light emission paths in the OPA chip. Furthermore, it is necessary to select one or more antennas from the OPA chip for measurement, and the number of antennas selected affects the performance of the OPA chip.

[0006] Therefore, how to achieve non-destructive testing of OPA chips is a problem that urgently needs to be solved. Summary of the Invention

[0007] This application provides a detection circuit and method for an optical phase array (OPA) chip to achieve non-destructive testing of the OPA chip without disrupting its internal layout design, thus saving testing costs and not affecting the performance of the OPA chip, thereby ensuring the reliability and safety of the lidar system containing the OPA chip.

[0008] In a first aspect, this application provides a detection circuit for an optical phase array (OPA) chip, comprising: a laser assembly, a first electrode, a second electrode, and a signal processing unit.

[0009] The first electrode and the second electrode are respectively disposed on the optical phase array (OPA) chip. The first electrode is used to load an AC voltage signal, and the second electrode is electrically connected to the signal processing unit.

[0010] Laser assembly for emitting lasers of varying optical power to an optical phase array (OPA) chip, so that the laser passes through the silicon waveguide of the OPA chip;

[0011] The first electrode is used to transmit AC voltage signals to the silicon waveguide;

[0012] The second electrode is used to transmit an alternating current signal to the signal processing unit, wherein the alternating current signal is generated based on the potential difference between the first electrode and the second electrode.

[0013] The signal processing unit is used to process the alternating current signal and output the processing result. When the processing result indicates that the conductivity of the silicon waveguide changes with the optical power of the laser, it is determined that the optical phase array (OPA) chip is working properly.

[0014] Through the detection circuit of the optical phase array (OPA) chip provided in the first aspect, the laser assembly emits lasers of different optical powers into the OPA chip, allowing these lasers to flow through the silicon waveguide of the OPA chip. This causes the conductivity of the silicon waveguide to change with the optical power of the laser. The first and second electrodes are respectively disposed on the upper cladding of the OPA chip. After an AC voltage signal is applied to the first electrode, the AC voltage signal forms an equivalent capacitance between the first electrode and the silicon waveguide of the OPA chip and is coupled into the silicon waveguide. Another equivalent capacitance is formed between the second electrode and the silicon waveguide, and an equivalent resistance is formed within the silicon waveguide. The AC voltage signal then flows through the silicon waveguide of the OPA chip and outputs an AC current signal through the second electrode. This AC current signal represents the relationship between the conductivity of the silicon waveguide of the OPA chip and the optical power of the laser. Based on the electrical connection between the second electrode and the signal processing unit, the signal processing unit can process the alternating current signal into a more easily detectable result and output the result. This result represents the relationship between the conductivity of the silicon waveguide in the OPA chip and the optical power of the laser. Specifically, when the processing result indicates a change in the conductivity of the OPA chip's silicon waveguide with the optical power of the laser, it can be determined that the OPA chip is functioning normally.

[0015] Therefore, by utilizing the conductivity of the silicon waveguide in the OPA chip to monitor the optical power of the laser, non-destructive testing of the OPA chip is achieved. In actual production, this facilitates the quality inspection and control of the OPA chip without damaging its internal layout design. No additional components need to be added inside the OPA chip, and the output power, number of light emission paths, and propagation path of the laser within the OPA chip are affected. It also ensures simultaneous multi-channel testing of the OPA chip (such as fixed-interval testing or continuous testing of several channels), allowing the tested OPA chip to remain usable. This saves testing costs and ensures the reliability and safety of the lidar system containing the OPA chip.

[0016] In one possible design, the signal processing unit includes a transimpedance amplifier and a lock-in amplifier;

[0017] The first terminal of the transimpedance amplifier is electrically connected to the second electrode, the second terminal of the transimpedance amplifier is electrically connected to the first terminal of the lock-in amplifier, the second terminal of the lock-in amplifier is used to input AC voltage signals, and the third and fourth terminals of the lock-in amplifier are used to output processing results.

[0018] A transimpedance amplifier is used to convert an alternating current signal into a first voltage signal and transmit the first voltage signal to a lock-in amplifier.

[0019] A lock-in amplifier is used to perform frequency shifting on a first voltage signal and an AC voltage signal to obtain a second voltage signal and a third voltage signal.

[0020] The lock-in amplifier is also used to filter the second voltage signal and output the filtered second voltage signal, and to filter the third voltage signal and output the filtered third voltage signal. When it is detected that the amplitude difference between the filtered second voltage signal and the filtered third voltage signal is a fixed value while the optical power of the laser remains constant, and changes with the change of the optical power of the laser, it is determined that the conductivity of the silicon waveguide changes with the change of the optical power of the laser.

[0021] Therefore, the signal processing unit can process the AC current signal into a more easily detectable result, which facilitates non-destructive testing of OPA chips and also helps to improve the efficiency and accuracy of non-destructive testing of OPA chips.

[0022] In one possible design, a lock-in amplifier is specifically used to multiply a first voltage signal with an AC voltage signal to obtain a second voltage signal; and to multiply the first voltage signal with an AC voltage signal that has been phase-flipped by 90 degrees to obtain a third voltage signal.

[0023] This facilitates the subsequent analysis of the filtered second and third voltage signals using orthogonal decomposition.

[0024] In one possible design, the laser component is specifically used to emit lasers of different optical powers to the optical phase array (OPA) chip by adjusting at least one parameter of the laser's intensity, frequency, or phase.

[0025] This provides multiple ways to obtain lasers with different optical powers, enriching the channels for obtaining lasers with different optical powers.

[0026] In one possible design, the first electrode and the second electrode are respectively disposed on the optical phase array (OPA) chip, including:

[0027] The output side of the end-face coupler in the optical phase array (OPA) chip, the upper and lower arms of each stage of the multimode interference (MMI), the upper and lower arms of the final stage of the multimode interference (MMI), or the input side of the antenna.

[0028] Therefore, the first and second electrodes can serve as monitoring points for the OPA chip's detection circuit to check whether the OPA chip is functioning properly. Thus, the OPA chip's detection circuit can use the first and second electrodes to detect whether any location / module within the OPA chip is functioning correctly.

[0029] Secondly, this application provides a detection method for an optical phase array (OPA) chip, which is applied to a detection device for an optical phase array (OPA) chip. The device includes a laser assembly, a first electrode, a second electrode, and a signal processing unit. The first electrode and the second electrode are respectively disposed on the optical phase array (OPA) chip. The first electrode is used to load an AC voltage signal, and the second electrode is electrically connected to the signal processing unit.

[0030] The method includes:

[0031] The laser assembly emits lasers of different optical powers into the optical phase array (OPA) chip so that the lasers pass through the silicon waveguide of the OPA chip.

[0032] The first electrode transmits the AC voltage signal to the silicon waveguide;

[0033] The second electrode transmits an alternating current signal to the signal processing unit, wherein the alternating current signal is generated based on the potential difference between the first electrode and the second electrode;

[0034] The signal processing unit processes the alternating current signal and outputs the processing result. When the processing result indicates that the conductivity of the silicon waveguide changes with the optical power of the laser, it is determined that the optical phase array (OPA) chip is working properly.

[0035] In one possible design, the signal processing unit includes a transimpedance amplifier and a lock-in amplifier; wherein, the first terminal of the transimpedance amplifier is electrically connected to the second electrode, the second terminal of the transimpedance amplifier is electrically connected to the first terminal of the lock-in amplifier, the second terminal of the lock-in amplifier is used to input an AC voltage signal, and the third and fourth terminals of the lock-in amplifier are used to output the processing result.

[0036] The signal processing unit processes the alternating current signal and outputs the processing results, including:

[0037] The transimpedance amplifier converts the alternating current signal into a first voltage signal and transmits the first voltage signal to the lock-in amplifier.

[0038] The lock-in amplifier performs frequency shifting on the first voltage signal and the AC voltage signal to obtain the second voltage signal and the third voltage signal;

[0039] The lock-in amplifier filters the second voltage signal and outputs the filtered second voltage signal. It also filters the third voltage signal and outputs the filtered third voltage signal. When the amplitude difference between the filtered second voltage signal and the filtered third voltage signal is detected to be a fixed value while the optical power of the laser remains constant, and changes with the optical power of the laser, it is determined that the conductivity of the silicon waveguide changes with the optical power of the laser.

[0040] In one possible design, the lock-in amplifier performs frequency shifting on the first voltage signal and the AC voltage signal to obtain a second voltage signal and a third voltage signal, including:

[0041] The lock-in amplifier multiplies the first voltage signal with the AC voltage signal to obtain the second voltage signal;

[0042] The lock-in amplifier multiplies the first voltage signal with an AC voltage signal that has been flipped 90 degrees in phase to obtain the third voltage signal.

[0043] In one possible design, the laser assembly emits laser light of varying powers to the optical phase array (OPA) chip, including:

[0044] The laser assembly emits lasers of different optical powers into the optical phase array (OPA) chip by adjusting at least one parameter of the laser's intensity, frequency, or phase.

[0045] In one possible design, the first electrode and the second electrode are respectively disposed on the optical phase array (OPA) chip, including:

[0046] The output side of the end-face coupler in the optical phase array (OPA) chip, the upper and lower arms of each stage of the multimode interference (MMI), the upper and lower arms of the final stage of the multimode interference (MMI), or the input side of the antenna.

[0047] The beneficial effects of the detection method for the optical phase array OPA chip provided in the second aspect and the various possible designs of the second aspect can be found in the first aspect and the various possible implementations of the first aspect, and will not be repeated here. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the detection circuit of an OPA chip provided in an embodiment of this application;

[0049] Figure 2 This is a schematic flowchart of a detection method for an OPA chip provided in an embodiment of this application;

[0050] Figure 3 This is a schematic diagram of the structure of a signal processing unit provided in an embodiment of this application;

[0051] Figure 4 This is a flowchart illustrating a detection method for an OPA chip according to an embodiment of this application.

[0052] Explanation of reference numerals in the attached figures:

[0053] 1—Detection circuit of OPA chip;

[0054] 11—Laser assembly; 12—First electrode; 13—Second electrode; 14—Signal processing unit;

[0055] 2—OPA chip;

[0056] 21—Upper cladding; 22—Silicon waveguide; 23—Lower cladding; 24—Substrate;

[0057] Ve—AC voltage signal;

[0058] C1—First equivalent capacitance; C2—Second equivalent capacitance; R1—Equivalent resistance; I—AC current signal;

[0059] 141—Transimpedance amplifier; 142—Lock-in amplifier;

[0060] R2—Feedback resistor; A—Operational amplifier; L—Low-pass filter;

[0061] V1—First voltage signal;

[0062] V2—Second voltage signal; V3—Third voltage signal;

[0063] V4—The second voltage signal filtered; V5—The third voltage signal filtered. Detailed Implementation

[0064] In this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c alone can mean: a alone, b alone, c alone, a combination of a and b, a combination of a and c, a combination of b and c, or a, b, and c, where a, b, and c can be single or multiple. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms “center,” “longitudinal,” “lateral,” “up,” “down,” “left,” “right,” “front,” and “rear,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0065] Typically, the conductivity of an optical waveguide in an optical device changes with the incident light power. Therefore, as an optical device, the conductivity of the silicon waveguide in an OPA chip changes with the optical power of the laser light passing through it, but remains unchanged if the optical power of the laser light passing through it remains constant.

[0066] Based on the above description, this application provides a detection circuit and method for an OPA chip. By monitoring the change in the optical power of the laser passing through the silicon waveguide of the OPA chip by utilizing the change in the conductivity of the silicon waveguide of the OPA chip, it is possible to identify whether the OPA chip can work normally, achieving the purpose of non-destructive testing of the OPA chip without damaging the internal layout design of the OPA chip. This ensures that the tested OPA chip can still be used normally without affecting its performance, avoiding resource waste, and guaranteeing the reliability and safety of the lidar system containing the OPA chip.

[0067] The specific implementation of the detection circuit and method of the OPA chip in this application will be described in detail below with reference to specific embodiments.

[0068] Please see Figure 1 , Figure 1This is a schematic diagram of the detection circuit of an OPA chip provided in an embodiment of this application.

[0069] like Figure 1 As shown, the detection circuit 1 of the OPA chip may include: a laser assembly 11, a first electrode 12, a second electrode 13, and a signal processing unit 14.

[0070] Laser assembly 11 can provide lasers with various optical powers.

[0071] This application does not limit the manner in which the laser assembly 11 provides the laser or the specific magnitude of the laser's optical power. In some embodiments, the laser assembly 11 can provide lasers with various optical powers by adjusting the laser parameters.

[0072] This application does not limit the specific implementation of the laser component 11. For example, the laser component 11 may include a laser emitter and a controller. The controller can adjust the parameters of the laser emitted by the laser emitter, enabling the laser emitter to emit lasers of various optical powers.

[0073] The laser parameters mentioned above may include, but are not limited to, at least one of the following: light intensity, frequency, or phase. As long as the parameter can be satisfied, the light power of the laser can be adjusted.

[0074] The first electrode 12 and the second electrode 13 are respectively disposed on the OPA chip 2, such that both the first electrode 12 and the second electrode 13 are in electrical contact with the OPA chip 2.

[0075] This application does not limit the specific implementation of the OPA chip 2. In some embodiments, the OPA chip 2 may include: an end-face coupler, a phase shifter, and an antenna.

[0076] The system includes an end-face coupler for transmitting the input laser light to a phase shifter. The phase shifter controls the relative phase of the antenna. The phase shifter may include a multi-mode inferometer (MMI), and the multiple MMIs may be cascaded and electrically connected. The antenna is used to emit (or couple) the laser light into free space, or to emit (or couple) the laser light from free space.

[0077] This application does not limit the specific implementation of each module in OPA chip 2.

[0078] For any module in OPA chip 2, the module may include the following structure:

[0079] In some embodiments, the structure may include an upper cladding layer 21, a silicon waveguide 22, a lower cladding layer 23, and a substrate 24 stacked sequentially.

[0080] Alternatively, the structure may include an upper cladding 21, a silicon waveguide 22, and a substrate 24 stacked sequentially.

[0081] Among them, if the upper cladding 21 or the lower cladding has poor conductivity or is non-conductive, or has low absorption rate for a certain wavelength of laser light, silicon dioxide (S) can be used. i At least one of the following materials: O2), silicon nitride, silicon oxynitride, etc., and silicon waveguide 22 may be made of silicon material.

[0082] It can be seen that both the first electrode 12 and the second electrode 13 are located on the upper cladding 21.

[0083] The silicon waveguide 22 has a good ability to confine lasers, and this application does not limit the specific implementation of the silicon waveguide 22.

[0084] The substrate 24 has a certain mechanical strength, and this application does not limit the specific implementation of the substrate 24.

[0085] As can be seen, in the OPA chip 2, the first electrode 12 and the second electrode 13 can be located on the upper cladding 21 of the OPA chip 2, and their specific implementation can include at least one of the following: the output side of the end coupler, the upper and lower arms of each MMI stage, the upper and lower arms of the final MMI stage, or the input side of the antenna.

[0086] When the first electrode 12 and the second electrode 13 are respectively located on the output side of the end face coupler, the detection circuit 1 of the OPA chip can detect whether the end face coupler in the OPA chip 2 can work normally.

[0087] When the first electrode 12 and the second electrode 13 are located at the upper arm and lower arm of each MMI stage respectively, the detection circuit 1 of the OPA chip can detect whether each MMI stage of the phase shifter in the OPA chip 2 can work normally.

[0088] In this process, the upper and lower arms of each MMI stage need to maintain phase consistency. This is beneficial for the corresponding MMI to receive the maximum energy and for detecting whether the phase shifter in the OPA chip 2 is working at its optimal state.

[0089] When the first electrode 12 and the second electrode 13 are located on the upper arm and lower arm of the final stage MMI, respectively, the detection circuit 1 of the OPA chip can detect whether all modules in the OPA chip 2 containing the final stage MMI located before the final stage MMI can work normally.

[0090] In addition, the detection circuit 1 of the OPA chip can also measure the power at one end of the optical path with equal optical path length.

[0091] When the first electrode 12 and the second electrode 13 are respectively located on the input side of the antenna, the detection circuit 1 of the OPA chip can detect whether the antenna in the OPA chip 2 can work normally.

[0092] In addition, the detection circuit 1 of the OPA chip can also calibrate the power of the antenna input to the OPA chip 2. Furthermore, the detection circuit 1 of the OPA chip can calculate the loss caused by the equal optical path by subtracting the aforementioned power from the power at one end of the optical path mentioned above.

[0093] In summary, the first electrode 12 and the second electrode 13 can serve as monitoring points for the detection circuit 1 of the OPA chip to detect whether the OPA chip 2 can function properly. Therefore, the detection circuit 1 of the OPA chip can, with the aid of the first electrode 12 and the second electrode 13, detect whether any position / module within the OPA chip 2 can function properly.

[0094] It should be noted that this application is not limited to the above-described setup.

[0095] The first electrode 12 can be loaded with an AC voltage signal Ve through an AC power supply. This application does not limit the specific implementation of the first electrode 12. For example, the first electrode 12 can be conductive and made of a metallic material. This application also does not limit the specific magnitude of the AC voltage signal Ve, as long as the AC voltage signal Ve is AC current.

[0096] The second electrode 13 is electrically connected to the signal processing unit 14, enabling the second electrode 13 to transmit corresponding signals to the signal processing unit 14. Thus, the signal processing unit 14 can perform signal processing on the corresponding signals.

[0097] This application does not limit the specific implementation of the second electrode 13 and the signal processing unit 14. For example, the second electrode 13 is conductive and can be made of a metallic material. The signal processing unit 14 can be an integrated chip, a circuit composed of multiple components, or either of the aforementioned methods; this application does not limit its implementation in this regard.

[0098] Based on the above description, and in conjunction with Figure 2 This paper details the specific implementation of the OPA chip detection method described in this application.

[0099] Please see Figure 2 , Figure 2 This is a flowchart illustrating a detection method for an OPA chip according to an embodiment of this application.

[0100] like Figure 2 As shown, the detection method for the OPA chip in this application may include:

[0101] S101, The laser assembly emits lasers of different optical powers to the optical phase array (OPA) chip so that the lasers pass through the silicon waveguide of the OPA chip.

[0102] The laser assembly 11 can emit lasers of different optical powers to the OPA chip 2 via a means such as light, so that each type of laser can pass through the silicon waveguide 22 of the OPA chip 2.

[0103] Therefore, when the optical power of the laser changes, the conductivity of the silicon waveguide 22 can change accordingly, and the optical power of the laser can be monitored by utilizing the change in the conductivity of the silicon waveguide 22.

[0104] The optical power of the laser mentioned in this application may refer to the optical power of the laser emitted by the laser assembly 11, or the optical power of the laser coupled into the silicon waveguide 22.

[0105] S102, the first electrode transmits the AC voltage signal to the silicon waveguide.

[0106] When an AC voltage signal Ve is applied to the first electrode 12, the first electrode 12 can transmit the AC voltage signal Ve to the silicon waveguide 22 of the OPA chip 2. The AC voltage signal Ve is an AC signal with frequency f applied to the first electrode 12.

[0107] Since the OPA chip 2 includes at least a stacked upper cladding layer 21 and a silicon waveguide 22, and the first electrode 12 and the second electrode 13 are respectively disposed on the upper cladding layer 21, the AC voltage signal Ve can form a first equivalent capacitance C1 between the first electrode 12 and the silicon waveguide 22 and couple it into the silicon waveguide 22, form a second equivalent capacitance C2 between the second electrode 13 and the silicon waveguide 22, and form an equivalent resistance R1 in the silicon waveguide 22.

[0108] Therefore, the first terminal of the first equivalent capacitor C1 is electrically connected to the first electrode 12, the second terminal of the first equivalent capacitor C1 is electrically connected to the first terminal of the equivalent resistor R1, the first terminal of the second equivalent capacitor C2 is electrically connected to the second electrode 13, and the second terminal of the second equivalent capacitor C2 is electrically connected to the second terminal of the equivalent resistor R1.

[0109] The first equivalent capacitance C1 and the second equivalent capacitance C2 are the coupling capacitances between the upper cladding 21 and the silicon waveguide 22 inside the OPA chip 2. The equivalent resistance R1 is the resistance value of the silicon waveguide 22 inside the OPA chip 2. The resistance value of the equivalent resistance R1 is related to the width, length, height, and conductivity of the silicon waveguide 22.

[0110] It should be noted that the first equivalent capacitor C1, the second equivalent voltage C2, and the equivalent resistance R1 are not actual components, but are formed based on the first electrode 12, the second electrode 13, the upper cladding 21 of the OPA chip 2, the silicon waveguide 22 of the OPA chip 2, and the AC voltage signal Ve.

[0111] S103. The second electrode transmits an alternating current signal to the signal processing unit, wherein the alternating current signal is generated based on the potential difference between the first electrode and the second electrode.

[0112] After the AC voltage signal Ve flows through the silicon waveguide 22 of the OPA chip 2, an AC current signal I can be output on the second electrode 13. The AC current signal I is the current signal flowing through the silicon waveguide 22 of the OPA chip 2, and the AC current signal I is generated based on the potential difference between the first electrode 12 and the second electrode 13.

[0113] Since the second electrode 13 is electrically connected to the signal processing unit 14, the second electrode 13 can transmit the alternating current signal I to the signal processing unit 14.

[0114] When the optical power of the laser changes, the laser passes through the silicon waveguide 22 of the OPA chip 2, causing a change in the conductivity of the silicon waveguide 22. Therefore, the AC current signal I changes with the change in the optical power of the laser passing through the silicon waveguide 22 of the OPA chip 2; that is, the AC current signal I can represent the relationship between the conductivity of the silicon waveguide 22 of the OPA chip 2 and the optical power of the laser.

[0115] S104 The signal processing unit processes the AC current signal and outputs the processing result. When it detects that the processing result indicates that the conductivity of the silicon waveguide changes with the optical power of the laser, it determines that the optical phase array (OPA) chip can work normally.

[0116] Considering that the alternating current signal I is not easy to detect, the signal processing unit 14 can perform signal processing on the alternating current signal I, such as signal conversion, spectrum shifting, and noise filtering, to obtain the processing result and output the processing result.

[0117] The processing result can represent the alternating current signal I, which indicates the relationship between the conductivity of the silicon waveguide 22 of the OPA chip 2 and the optical power of the laser.

[0118] Therefore, by detecting the processing results, the change in the optical power of the laser passing through the silicon waveguide 22 of the OPA chip 2 can be detected, thus realizing the detection of the OPA chip 2.

[0119] When the processing results indicate that the conductivity of the silicon waveguide 22 of the OPA chip 2 changes with the optical power of the laser, it can be determined that the OPA chip 2 is functioning normally.

[0120] If the processing results indicate that the conductivity of the silicon waveguide 22 of the OPA chip 2 does not change with the change in the optical power of the laser, it can be determined that the OPA chip 2 is not working properly.

[0121] The detection circuit for the OPA chip provided in this application emits lasers of varying optical power into the OPA chip via a laser assembly. These lasers flow through the silicon waveguide of the OPA chip, causing a change in the conductivity of the silicon waveguide in response to the laser's optical power. A first electrode and a second electrode are respectively disposed on the upper cladding of the OPA chip. After an AC voltage signal is applied to the first electrode, the AC voltage signal forms an equivalent capacitance between the first electrode and the silicon waveguide of the OPA chip and is coupled into the silicon waveguide. Another equivalent capacitance is formed between the second electrode and the silicon waveguide, and an equivalent resistance is also formed within the silicon waveguide. The AC voltage signal then flows through the silicon waveguide of the OPA chip and outputs an AC current signal via the second electrode. This AC current signal represents the relationship between the conductivity of the silicon waveguide of the OPA chip and the optical power of the laser. Based on the electrical connection between the second electrode and the signal processing unit, the signal processing unit can process the alternating current signal into a more easily detectable result and output the result. This result represents the relationship between the conductivity of the silicon waveguide in the OPA chip and the optical power of the laser. Specifically, when the processing result indicates a change in the conductivity of the OPA chip's silicon waveguide with the optical power of the laser, it can be determined that the OPA chip is functioning normally.

[0122] Therefore, by utilizing the conductivity of the silicon waveguide in the OPA chip to monitor the optical power of the laser, non-destructive testing of the OPA chip is achieved. In actual production, this facilitates the quality inspection and control of the OPA chip without damaging its internal layout design. No additional components need to be added inside the OPA chip, and the output power, number of light emission paths, and propagation path of the laser within the OPA chip are affected. It also ensures simultaneous multi-channel testing of the OPA chip (such as fixed-interval testing or continuous testing of several channels), allowing the tested OPA chip to remain usable. This saves testing costs and ensures the reliability and safety of the lidar system containing the OPA chip.

[0123] In this application, the signal processing unit 14 may include various implementation methods, so that the signal processing unit 14 can process the alternating current signal I into a processing result, and the processing result can represent the relationship between the conductivity of the silicon waveguide 22 of the OPA chip 2 and the optical power of the laser, and also make it easier for the user to detect the processing result.

[0124] Below, in conjunction with Figure 3 This paper details the specific implementation of the signal processing unit 14 in this application.

[0125] Please see Figure 3 , Figure 3 This is a schematic diagram of the structure of a signal processing unit provided in an embodiment of this application.

[0126] For ease of explanation, Figure 3 In the example, the OPA chip 2 adopts a structure consisting of an upper cladding layer 21, a silicon waveguide 22, a lower cladding layer 23, and a substrate 24 stacked sequentially.

[0127] like Figure 3 As shown, the signal processing unit 14 of this application may include a transimpedance amplifier (TIA) 141 and a lock-in amplifier 142.

[0128] The first terminal of the transimpedance amplifier 141 is electrically connected to the second electrode 13, and the second terminal of the transimpedance amplifier 141 is electrically connected to the first terminal of the lock-in amplifier 142. The second terminal of the lock-in amplifier 142 is used to input the AC voltage signal Ve, and the third and fourth terminals of the lock-in amplifier 142 are used to output the processing result.

[0129] A transimpedance amplifier 141 is used to convert current to voltage. This application does not limit the specific implementation of the transimpedance amplifier 141. For example, the transimpedance amplifier 141 may include a feedback resistor R2 and an operational amplifier A. The feedback resistor R2 is electrically connected between the input and output terminals of the operational amplifier A. Additionally, the operational amplifier A includes a ground terminal and a power supply terminal to maintain normal operation.

[0130] A lock-in amplifier 142 is used to perform spectrum shifting of a signal. This application does not limit the specific implementation of the lock-in amplifier 142. For example, a mixer or multiple multipliers can be used in the lock-in amplifier 142 to perform spectrum shifting of the signal.

[0131] The lock-in amplifier 142 is also used to filter out noise in the signal. This application does not limit the specific implementation of the lock-in amplifier 142. For example, a low-pass filter L can be used in the lock-in amplifier 142 to filter out noise in the signal.

[0132] Based on the above description, and in conjunction with Figure 4 This paper details the specific implementation of the OPA chip detection method described in this application.

[0133] Please see Figure 4 , Figure 4 This is a flowchart illustrating a detection method for an OPA chip according to an embodiment of this application.

[0134] like Figure 4 As shown, the detection method for the OPA chip in this application may include:

[0135] S201, the transimpedance amplifier converts the AC current signal into a first voltage signal and transmits the first voltage signal to the lock-in amplifier.

[0136] After the alternating current signal I is output to the transimpedance amplifier 141, the transimpedance amplifier 141 can convert the alternating current signal I into a first voltage signal V1. The first voltage signal V1 represents the relationship between the conductivity of the silicon waveguide 22 of the OPA chip 2 and the optical power of the laser, as indicated by the alternating current signal I. Thus, the signal conversion of the alternating current signal I is achieved.

[0137] Based on the electrical connection between the transimpedance amplifier 141 and the lock-in amplifier 142, the transimpedance amplifier 141 can transmit the first voltage signal V1 to the lock-in amplifier 142.

[0138] S202, The lock-in amplifier performs frequency shifting on the first voltage signal and the AC voltage signal to obtain the second voltage signal and the third voltage signal.

[0139] Upon receiving the first voltage signal V1, the lock-in amplifier 142 splits the first voltage signal V1 into two paths, using the AC voltage signal Ve as the modulation signal. The lock-in amplifier 142 then performs frequency shifting on the first voltage signal V1 and the AC voltage signal Ve, respectively, to obtain the second voltage signal V2 and the third voltage signal V3. Thus, the frequency shifting of the signal is completed.

[0140] In some embodiments, the lock-in amplifier 142 can multiply the first voltage signal V1 in one path with the AC voltage signal Ve to obtain the second voltage signal V2. The lock-in amplifier 142 can also multiply the first voltage signal V1 in another path with the AC voltage signal Ve that has been flipped by 90 degrees to obtain the third voltage signal V3.

[0141] This facilitates the subsequent analysis of the filtered second voltage signal V4 and the filtered third voltage signal V5 using orthogonal decomposition.

[0142] S203, the lock-in amplifier filters the second voltage signal and outputs the filtered second voltage signal, filters the third voltage signal and outputs the filtered third voltage signal. When it is detected that the amplitude difference between the filtered second voltage signal and the filtered third voltage signal is a fixed value as the optical power of the laser remains constant, and changes as the optical power of the laser changes, it is determined that the conductivity of the silicon waveguide changes with the optical power of the laser.

[0143] Upon receiving the second voltage signal V2, the lock-in amplifier 142 filters the second voltage signal V2 and outputs the filtered second voltage signal V4. Upon receiving the third voltage signal V3, the lock-in amplifier 142 filters the third voltage signal V3 and outputs the filtered third voltage signal V5. This filters out noise in the signal, which is beneficial for subsequent detection.

[0144] The amplitude difference between the filtered second voltage signal V4 and the filtered third voltage signal V5 can represent the alternating current signal I, which represents the relationship between the conductivity of the silicon waveguide 22 of the OPA chip 2 and the optical power of the laser.

[0145] Therefore, by detecting the amplitude difference, the change in the optical power of the laser passing through the silicon waveguide 22 of the OPA chip 2 can be detected, thus achieving non-destructive testing of the OPA chip 2.

[0146] When the amplitude difference is detected to be a fixed value as the optical power of the laser remains constant, and changes as the optical power of the laser changes, it can be determined that the conductivity of the silicon waveguide 22 changes with the optical power of the laser, and it can also be determined that the OPA chip 2 can work normally.

[0147] In summary, the signal processing unit 14 processes the AC current signal I into a more easily detectable result, which facilitates the non-destructive testing of the OPA chip 2 and helps improve the efficiency and accuracy of the non-destructive testing of the OPA chip 2.

[0148] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This program can be stored in a computer-readable storage medium, and when executed, it can include the processes described in the above method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM or random access memory (RAM), magnetic disks, or optical disks.

[0149] Finally, it should be noted that the above embodiments are merely specific implementations of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A detection circuit for an optical phase array (OPA) chip, characterized in that, include: Laser assembly, first electrode, second electrode, and signal processing unit; The first electrode and the second electrode are respectively disposed on the optical phase array (OPA) chip. The first electrode is used to load an AC voltage signal, and the second electrode is electrically connected to the signal processing unit. The laser assembly is used to emit lasers of different optical powers to the optical phase array (OPA) chip so that the lasers pass through the silicon waveguide of the OPA chip. The first electrode is used to transmit the AC voltage signal into the silicon waveguide; The second electrode is used to transmit an alternating current signal to the signal processing unit, wherein the alternating current signal is generated based on the potential difference between the first electrode and the second electrode; The signal processing unit is used to process the alternating current signal and output the processing result. When it is detected that the processing result indicates that the conductivity of the silicon waveguide changes with the optical power of the laser, it is determined that the optical phase array (OPA) chip can work normally. The OPA chip includes at least a stacked upper cladding and a silicon waveguide, and the first electrode and the second electrode are respectively disposed on the upper cladding.

2. The circuit according to claim 1, characterized in that, The signal processing unit includes: a transimpedance amplifier and a lock-in amplifier; Wherein, the first terminal of the transimpedance amplifier is electrically connected to the second electrode, the second terminal of the transimpedance amplifier is electrically connected to the first terminal of the lock-in amplifier, the second terminal of the lock-in amplifier is used to input the AC voltage signal, and the third and fourth terminals of the lock-in amplifier are used to output the processing result; The transimpedance amplifier is used to convert the alternating current signal into a first voltage signal and transmit the first voltage signal to the lock-in amplifier; The lock-in amplifier is used to perform frequency shifting on the first voltage signal and the AC voltage signal to obtain a second voltage signal and a third voltage signal. The lock-in amplifier is further configured to filter the second voltage signal and output the filtered second voltage signal, filter the third voltage signal and output the filtered third voltage signal, wherein when it is detected that the amplitude difference between the filtered second voltage signal and the filtered third voltage signal is a fixed value as the optical power of the laser remains constant, and changes as the optical power of the laser changes, it is determined that the conductivity of the silicon waveguide changes with the optical power of the laser.

3. The circuit according to claim 2, characterized in that, The lock-in amplifier is specifically used to multiply the first voltage signal by the AC voltage signal to obtain the second voltage signal; and to multiply the first voltage signal by the AC voltage signal with its phase flipped by 90 degrees to obtain the third voltage signal.

4. The circuit according to any one of claims 1-3, characterized in that, The laser assembly is specifically used to emit lasers of different optical powers to the optical phase array (OPA) chip by adjusting at least one parameter of the laser's intensity, frequency, or phase.

5. The circuit according to any one of claims 1-3, characterized in that, The first electrode and the second electrode are respectively disposed on the optical phase array (OPA) chip in the following ways: At least one of the following: the output side of the end-face coupler in the optical phase array (OPA) chip, the upper and lower arms of each stage of the multimode interference (MMI), the upper and lower arms of the final stage of the multimode interference (MMI), or the input side of the antenna.

6. A method for detecting an optical phase array (OPA) chip, characterized in that, A detection device for an optical phase array (OPA) chip includes a laser assembly, a first electrode, a second electrode, and a signal processing unit. The first electrode and the second electrode are respectively disposed on the OPA chip. The first electrode is used to apply an AC voltage signal, and the second electrode is electrically connected to the signal processing unit. The method includes: The laser assembly emits lasers of different optical powers into the optical phase array (OPA) chip, so that the lasers pass through the silicon waveguide of the OPA chip; the first electrode transmits the AC voltage signal into the silicon waveguide; The second electrode transmits an alternating current signal to the signal processing unit, wherein the alternating current signal is generated based on the potential difference between the first electrode and the second electrode; The signal processing unit processes the alternating current signal and outputs the processing result. When the processing result indicates that the conductivity of the silicon waveguide changes with the optical power of the laser, it is determined that the optical phase array (OPA) chip is functioning normally. The OPA chip includes at least a stacked upper cladding and a silicon waveguide, and the first electrode and the second electrode are respectively disposed on the upper cladding.

7. The method according to claim 6, characterized in that, The signal processing unit includes a transimpedance amplifier and a lock-in amplifier; wherein, the first terminal of the transimpedance amplifier is electrically connected to the second electrode, the second terminal of the transimpedance amplifier is electrically connected to the first terminal of the lock-in amplifier, the second terminal of the lock-in amplifier is used to input the AC voltage signal, and the third and fourth terminals of the lock-in amplifier are used to output the processing result. The signal processing unit performs signal processing on the alternating current signal and outputs the processing result, including: The transimpedance amplifier converts the alternating current signal into a first voltage signal and transmits the first voltage signal to the lock-in amplifier; The lock-in amplifier performs frequency shifting on the first voltage signal and the AC voltage signal to obtain a second voltage signal and a third voltage signal; The lock-in amplifier filters the second voltage signal and outputs the filtered second voltage signal, and filters the third voltage signal and outputs the filtered third voltage signal. When it is detected that the amplitude difference between the filtered second voltage signal and the filtered third voltage signal is a fixed value while the optical power of the laser remains constant, and changes with the change in the optical power of the laser, it is determined that the conductivity of the silicon waveguide changes with the change in the optical power of the laser.

8. The method according to claim 7, characterized in that, The lock-in amplifier performs frequency shifting on the first voltage signal and the AC voltage signal to obtain a second voltage signal and a third voltage signal, including: The lock-in amplifier multiplies the first voltage signal with the AC voltage signal to obtain the second voltage signal; The lock-in amplifier multiplies the first voltage signal with the AC voltage signal that has been flipped by 90 degrees to obtain the third voltage signal.

9. The method according to any one of claims 6-8, characterized in that, The laser assembly emits lasers of different optical powers toward the optical phase array (OPA) chip, including: The laser assembly emits lasers of different optical powers into the optical phase array (OPA) chip by adjusting at least one parameter of the laser's intensity, frequency, or phase.

10. The method according to any one of claims 6-8, characterized in that, The first electrode and the second electrode are respectively disposed on the optical phase array (OPA) chip in the following ways: At least one of the following: the output side of the end-face coupler in the optical phase array (OPA) chip, the upper and lower arms of each stage of the multimode interference (MMI), the upper and lower arms of the final stage of the multimode interference (MMI), or the input side of the antenna.

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