An Automatic Testing Method and System for Gain Chip Parameters Based on LM-TL

Abstract

The present invention provides an automatic test method and system for gain chip parameters based on LM-TL, which relates to the technical field of chip testing. The method includes: connecting a sample gain chip to a Littman-Metcalf type tunable laser, setting test parameters, and making preparations before testing; sequentially performing optical power testing, optical wavelength testing, and amplified spontaneous emission spectrum testing on the sample gain chip to obtain optical power parameter data, optical wavelength parameter data, and amplified spontaneous emission spectrum data; analyzing the optical power parameter data, optical wavelength parameter data, and amplified spontaneous emission spectrum data to determine whether the sample gain chip is qualified, and obtaining gain chip parameters and test results; by using a wide-range free-space optical external cavity swept-frequency laser source as a test device, the present invention automatically tests and analyzes the characteristic parameters of half-butterfly packaged gain chips with different batches, different waveguide beam emission angles, and different lasing center wavelengths.

Description

Technical Field

[0001] The present invention belongs to the technical field of chip testing, and in particular relates to an automatic test method and system for gain chip parameters based on LM-TL. Background Technique

[0002] The statements in this part only provide background technical information related to the present invention, and do not necessarily constitute prior art.

[0003] A wide-range free-space optical external cavity swept-frequency laser source (also known as a Littman-Metcalf type tunable laser, abbreviated as LM-TL) has been widely used in high-speed coherent optical communication networks based on high-order optical modulation formats, fiber three-dimensional shape frequency-domain sensing, linear swept-frequency trace gas detection, and autonomous driving due to its outstanding advantages such as single longitudinal mode, narrow linewidth, continuously tunable output wavelength, and low phase noise. However, in the operation and output process of traditional LM-TL, the realization of wide-range and narrow-linewidth linearly continuously tunable laser output seriously depends on the accurate calibration of the characteristic optical parameters of the gain chip.

[0004] Traditional in-chip test systems often use probes and test instruments to calibrate the characteristic parameters of gain chips before the gain chips are processed and sliced. Through the storage module, the calibration data of the characteristic parameters of each tested gain chip are recorded, and a complex interactive parsing algorithm is used to invert the calibration data into a certain process parameter graph that can distinguish the electrical performance of the gain chip. By comparing with the standard value, gain chips with incomplete structure and unqualified electrical performance are eliminated, but the optical characteristic parameters of the laser gain chip cannot be effectively characterized. Currently, for the test of the optical characteristic parameters of gain chips, mainly through the optical coupling output method, several parameters such as its spectrum are manually calibrated, and the calibration results are easily affected by human subjective factors, resulting in the overall performance parameters of the sample gain chips being difficult to be compatible with LM-TL. Obviously, using the traditional in-chip test system as a test device can only calibrate the electrical characteristics of the sample gain chips. For half-butterfly packaged gain chips with different batches, different waveguide beam emission angles, and different lasing center wavelengths, due to factors such as their threshold current, 3dB bandwidth, and the diversity of different waveguide beam emission angles, the calibration process of the optical characteristic parameters of the sample gain chips is complex, time-consuming, has large errors, and is not universal, making it difficult to meet the application requirements of LM-TL in the field of high-speed coherent optical communication; at the same time, the non-targeted gain chip characteristic parameter test system also leads to an inefficient test process and increased costs.

[0005] Therefore, there are problems in the existing solutions that the calibration process of the characteristic parameters of the unencapsulated gain chip highly depends on the on-chip test system, the multi-thread interaction algorithm is complex, the whole test system is expensive, the optical characteristic parameters of the encapsulated gain chip cannot effectively characterize the overall performance of the sample gain chip, and the compatibility and accuracy of the LM-TL are easily affected by the manual calibration and screening factors, resulting in large differences in the output index performance of the LM-TL. Summary of the Invention

[0006] To overcome the above deficiencies of the prior art, the present invention provides an automatic test method and system for gain chip parameters based on LM-TL. By using a wide-range free-space optical external cavity swept-frequency laser source (Littman-Metcalf type tunable laser, hereinafter referred to as LM-TL) as the test device, the characteristic parameters of half-butterfly encapsulated gain chips with different batches, different waveguide beam emission angles, and different lasing center wavelengths are automatically tested and analyzed.

[0007] To achieve the above object, one or more embodiments of the present invention provide the following technical solutions:

[0008] The first aspect of the present invention provides an automatic test method for gain chip parameters based on LM-TL;

[0009] An automatic test method for gain chip parameters based on LM-TL includes:

[0010] Connect the sample gain chip to the Littman-Metcalf type tunable laser, set the test parameters, and make preparations before the test;

[0011] Perform optical power test, optical wavelength test, and amplified spontaneous emission spectrum test on the sample gain chip in sequence to obtain optical power parameter data, optical wavelength parameter data, and amplified spontaneous emission spectrum data;

[0012] Analyze the optical power parameter data, optical wavelength parameter data, and amplified spontaneous emission spectrum data to determine whether the sample gain chip is qualified, and obtain the gain chip parameters and test results.

[0013] Further, the preparations before the test are specifically as follows:

[0014] Connect the sample gain chip to the Littman-Metcalf type tunable laser;

[0015] Start the Littman-Metcalf type tunable laser;

[0016] Read the drive current parameter of the control circuit driving the sample gain chip, the spatial position parameter of the actuator, the temperature parameter of the support plate, the angle of the angle adjustment mechanism, and the channel position of the optical switch;

[0017] Check the connection of the sample gain chip;

[0018] Start the high-precision thermostat and read the temperature value of the high-precision thermostat;

[0019] Set the test parameters, including the simulated temperature of the high-precision thermostat, the sampling rate of the optical power meter, the wavelength resolution of the optical wavelength meter, the wavelength resolution of the spectrometer, multiple driving currents arranged at equal intervals from small to large for the sample gain chip, the simulated temperature of the support plate, and the angle of the angle adjustment mechanism.

[0020] Furthermore, for the optical power test, the specific steps are as follows:

[0021] Place the optical switch at the channel position for optical power test;

[0022] According to the set test parameters, control the simulated temperature of the high-precision thermostat, the simulated temperature of the support plate, and the angle of the angle adjustment mechanism, apply multiple different driving currents to the sample gain chip respectively, and record the optical power data under different driving currents to obtain a set of optical power distribution data;

[0023] Increase the angle of the angle adjustment mechanism by 5°, and re-measure a set of optical power distribution data.

[0024] Analyze the two sets of optical power distribution data to obtain the optical power parameter data of the sample gain chip, including the power vs. injection current change distribution trace, threshold current, and optimal operating current.

[0025] Furthermore, perform a difference operation on the corresponding points of the two sets of optical power distribution data to obtain a set of difference distribution data, and draw the power vs. injection current change distribution trace according to the difference distribution data;

[0026] In a set of difference distribution data, the first driving current value where the difference distribution data is greater than the pre-set optical power value is the threshold current;

[0027] Calculate the slope between adjacent points in the second set of optical power distribution data to obtain a set of slope values. The driving current value with the smallest slope is the optimal operating current.

[0028] Furthermore, for the optical wavelength test, the specific steps are as follows:

[0029] Place the optical switch at the channel position for optical wavelength test;

[0030] According to the set test parameters and the threshold current obtained in the optical power test, control the simulated temperature of the high-precision thermostat, the simulated temperature of the support plate, and the angle of the angle adjustment mechanism, apply driving currents higher than the threshold current obtained in the optical power test to the sample gain chip respectively, and record the resonant wavelength data under different driving currents to obtain the optical wavelength distribution data;

[0031] Analyze the optical wavelength distribution data to obtain the optical wavelength parameter data of the sample gain chip, including the distribution trace of the lasing wavelength varying with the drive current and the resonance scanning range.

[0032] Furthermore, the steps of the amplified spontaneous emission spectrum test are as follows:

[0033] Place the optical switch at the channel position for the amplified spontaneous emission spectrum test;

[0034] According to the set test parameters and the threshold current obtained in the optical power test, control the simulated temperature of the high-precision constant temperature box, the simulated temperature of the support plate, and the angle of the angle adjustment mechanism, apply a specified current to the sample gain chip respectively, and record the amplified spontaneous emission spectrum data at the specified current to obtain the amplified spontaneous emission spectrum distribution data, where the specified current is the threshold current plus a specified offset;

[0035] Analyze the amplified spontaneous emission spectrum distribution data to obtain the amplified spontaneous emission spectrum parameter data of the sample gain chip, including the bandwidth, spectral ripple, and beam exit angle.

[0036] Furthermore, the determination of whether the sample gain chip is qualified includes four situations:

[0037] If the power difference between two corresponding points below the threshold current in the optical power difference distribution data is less than a preset power value, it is unqualified;

[0038] If the resonance scanning range is less than or equal to a preset resonance center wavelength range, it is unqualified;

[0039] If the absolute value of the power difference between two adjacent points in the amplified spontaneous emission spectrum distribution data is greater than or equal to a preset power value, it is unqualified;

[0040] If all the above three situations are satisfied simultaneously, it is qualified.

[0041] The second aspect of the present invention provides an automatic test system for gain chip parameters based on LM-TL.

[0042] An automatic test system for gain chip parameters based on LM-TL includes a test preparation module, a test implementation module, and a data analysis module;

[0043] The test preparation module is configured to: connect the sample gain chip to a Littman-Metcalf type tunable laser, set the test parameters, and make preparations before the test;

[0044] A test execution module, configured to: sequentially perform an optical power test, an optical wavelength test, and an amplified spontaneous emission spectrum test on a sample gain chip to obtain optical power parameter data, optical wavelength parameter data, and amplified spontaneous emission spectrum data;

[0045] A data analysis module, configured to: analyze the optical power parameter data, the optical wavelength parameter data, and the amplified spontaneous emission spectrum data to determine whether the sample gain chip is qualified, and obtain gain chip parameters and test results.

[0046] The third aspect of the present invention provides a computer-readable storage medium, on which a program is stored, and when the program is executed by a processor, the steps in a method for automatically testing gain chip parameters based on LM-TL as described in the first aspect of the present invention are implemented.

[0047] The fourth aspect of the present invention provides an electronic device, including a memory, a processor, and a program stored on the memory and executable on the processor. When the processor executes the program, the steps in a method for automatically testing gain chip parameters based on LM-TL as described in the first aspect of the present invention are implemented.

[0048] The above one or more technical solutions have the following beneficial effects:

[0049] By using a wide-range free-space optical external cavity swept-frequency laser source (Littman-Metcalf type tunable laser, abbreviated as LM-TL) as a test device, the characteristic parameters of semi-butterfly packaged gain chips with different batches, different waveguide beam output angles, and different lasing center wavelengths are automatically tested. Based on the characteristics that the optical characteristic parameters of the semi-butterfly packaged gain chip are sensitive to free-space optical feedback, through in-depth analysis of test traces such as the output optical power of the pigtail fiber versus the injection current, the tuning wavelength versus the coupled output optical power, and the tuning wavelength versus the threshold current, the efficient and highly accurate automatic testing and automatic analysis of the optical characteristic parameters of the semi-butterfly packaged gain chip are realized, providing advanced test instruments for fields such as intelligent high-speed coherent network reconfigurable transmission, cross-correlation frequency-domain decoupled fiber three-dimensional shape sensing, high-precision gas spectroscopy measurement, and autonomous driving. At the same time, it further expands the application range of the Littman-Metcalf type tunable laser, adds application scenarios for LM-TL, and promotes the rapid development of the wide-range free-space optical external cavity tunable laser industry.

[0050] The present invention solves the problems that in the traditional in-chip test system for calibrating the characteristic parameters of unencapsulated gain chips, the multi-thread interaction algorithm is complex and the whole test system is expensive, and the optical characteristic parameters of the encapsulated gain chips cannot effectively characterize the compatibility of the overall performance of the sample gain chips with LM-TL, and the accuracy is easily affected by manual calibration and screening factors, resulting in large differences in the output index performance of LM-TL; it solves the problems that the calibration process of the chip optical characteristic parameters in the LM-TL system is complex, time-consuming, has large errors and is not universal; it further expands the application scope of the Littman-Metcalf type tunable laser, adds application scenarios for LM-TL, and promotes the rapid development of the wide-range free-space optical external cavity tunable laser industry.

[0051] Advantages of additional aspects of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The accompanying drawings forming a part of this specification are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0053] Figure 1 It is a flowchart of the method for the first embodiment.

[0054] Figure 2 It is a structural diagram of the automatic test device for gain chip parameters in the first embodiment.

[0055] Figure 3 It is a structural diagram of the Littman-Metcalf type tunable laser in the first embodiment.

[0056] Figure 4 It is a system structural diagram of the second embodiment.

[0057] In the figure, 1. Littman-Metcalf type tunable laser; 2. High-precision constant temperature box; 3. Optical switch; 4. Optical power meter; 5. Optical wavelength meter; 6. Spectrometer; 7. Control computer; 101. Sample gain chip; 102. Beam shaping lens; 103. Optical frequency selection element; 104. Tunable mirror; 105. Actuator; 106. Support plate; 107. Control circuit; 108. Angle adjustment mechanism. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0058] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0059] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0060] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0061] Embodiment 1

[0062] This embodiment discloses an automatic test method for gain chip parameters based on LM-TL;

[0063] As Figure 1 shown, an automatic test method for gain chip parameters based on LM-TL includes:

[0064] Step S1: Connect the sample gain chip to a Littman-Metcalf type tunable laser, set the test parameters, and make preparations before the test;

[0065] The device for automatically testing the gain chip parameters, as Figure 2 shown, consists of the following parts:

[0066] (1) The Littman-Metcalf type tunable laser 1 mainly consists of a sample gain chip 101, a beam shaping lens 102, an optical frequency selection element 103, a tunable mirror 104, an actuator 105, a support plate 106, a control circuit 107, an angle adjustment mechanism 108, etc.

[0067] The structure of the Littman-Metcalf type tunable laser 1 is as Figure 3 shown. A wide-range free-space optical external cavity swept-frequency laser source (Littman-Metcalf type tunable laser, abbreviated as LM-TL) is used as the test equipment to automatically test the characteristic parameters of semi-butterfly packaged gain chips with different batches, different waveguide beam emission angles, and different lasing center wavelengths, and automatically analyze the test results such as the amplified spontaneous emission spectrum, resonance spectrum, power distribution data varying with the injection current, and lasing wavelength distribution data varying with the threshold current, so as to obtain the tunable range, optimal operating current, spectral ripple, and beam emission angle test data of the gain chip to be tested, and achieve accurate testing of the characteristic parameters of the semi-butterfly packaged gain chip. The specific composition is as follows:

[0068] The sample gain chip 101, typically an InP-based single-facet semiconductor gain chip in a semi-butterfly package, with a typical single-facet reflectivity of 0.005%, a typical 3dB bandwidth better than 80nm, is used for the generation of a free-space optical external cavity strong feedback seed source.

[0069] The beam shaping lens 102 is used for beam expansion and collimation of the laser beam output by the sample gain chip 101, and is typically a molded aspheric lens.

[0070] The optical frequency selection element 103 is generally a liquid crystal cell, a tunable filter, and a fixed grid filter, and is typically a blazed grating with a high groove density, and the typical groove density is greater than 900 lines / mm, and is used for the selection of resonant modes.

[0071] The tunable mirror 104 is used to realize the oscillation of photons with a specific frequency selected by the optical frequency selection element 103 in the external cavity, and is typically a gold-plated mirror.

[0072] The actuator 105 is used to precisely adjust the spatial position of the tunable mirror 104 and is driven by the control circuit 107.

[0073] The support plate 106 is integrated with a semiconductor refrigerator and a temperature sensor, and is used to stabilize the operating temperature of the Littman-Metcalf type tunable laser 1 and is controlled by the control circuit 107.

[0074] The control circuit 107 is controlled by the control computer 7, and is used to load the drive current of the sample gain chip 101, load the actuation voltage of the actuator 105, precisely adjust the temperature field of the support plate 106, and load the drive signal of the angle adjustment mechanism 108.

[0075] The angle adjustment mechanism 108 is driven by the control circuit 107 to switch the beam output angle of the measured sample gain chip 101.

[0076] (2) The high-precision constant temperature box 2 is used to reduce the measurement deviation caused by the change of the external environment temperature, and the typical temperature adjustment accuracy is ±1°C.

[0077] (3) The optical switch 3, a 1×3 optical switch, is controlled by the control computer 7 to switch the optical signal output channels of the optical power meter 4, the optical wavelength meter 5, and the spectrometer 6.

[0078] (4) The optical power meter 4 is used to extract the resonant optical power of the gain chip under different injection currents.

[0079] (5) The optical wavelength meter 5 is used to record the lasing wavelength.

[0080] (6) The spectrometer 6 is used to test the amplified spontaneous emission spectrum and the resonant spectrum, and the typical resolution is 0.02nm.

[0081] (7) The control computer 7 provides instruction initialization and drive signals for the actuator 105, support plate 106, control circuit 107, and angle adjustment mechanism 108 in the Littman-Metcalf type tunable laser, temperature control signals for the high-precision thermostat 2, instruction initialization and test channel switching for the optical switch 3, synchronous trigger acquisition signals for the optical power meter 4, optical wavelength meter 5, and spectrometer 6, and receives and processes distribution data information such as resonant power, lasing wavelength, and spectrum recorded in real time in the optical power meter 4, optical wavelength meter 5, and spectrometer 6.

[0082] For the device for automatically testing the above gain chip parameters, preparations before testing are carried out, and the specific steps are as follows:

[0083] Step S1-1: Connect the sample gain chip 101 to the Littman-Metcalf type tunable laser 1;

[0084] Step S1-2: The control computer 7 remotely controls the startup of the Littman-Metcalf type tunable laser 1;

[0085] Step S1-3: The control computer 7 reads the initial state parameters such as the drive current parameter of the sample gain chip 101 driven by the control circuit 107 in the Littman-Metcalf type tunable laser 1, the spatial position parameter of the actuator 105, the temperature parameter of the support plate 106, the angle of the angle adjustment mechanism 108, and the channel position CP[1~3] of the optical switch 3;

[0086] Step S1-4: Check the connection condition of the sample gain chip;

[0087] Step S1-5: The control computer 7 remotely controls the startup of the high-precision thermostat 2, and the control computer 7 reads the initial state parameters such as the temperature value of the high-precision thermostat 2;

[0088] Step S1-6: The user sets the simulated temperature ST of the high-precision thermostat 2, the sampling rate PS of the optical power meter 4 connected to channel CP[1], the wavelength resolution WR of the optical wavelength meter 5 connected to channel CP[2], the wavelength resolution OR of the spectrometer 6 connected to channel CP[3], the drive current IQ[1~M] of the sample gain chip 101, the simulated temperature ST1 of the support plate 106, and the angle ANG of the angle adjustment mechanism 108.

[0089] Among them, the M drive current values in IQ are arranged at equal intervals from small to large.

[0090] Step S2: Perform optical power test, optical wavelength test, and amplified spontaneous emission spectrum test on the sample gain chip in sequence to obtain optical power parameter data, optical wavelength parameter data, and amplified spontaneous emission spectrum data;

[0091] The specific steps for performing optical power test on the sample gain chip in sequence are as follows:

[0092] Step S2-1: Control the computer 7 to remotely start the optical switch 3 and place it at the channel position CP[1];

[0093] Step S2-2: Control the circuit 107 to load drive currents IQ[1~M] onto the laser chip (101) respectively, set the simulated temperatures to ST and ST1, and set the angle to ANG. Under M drive current conditions, measure and record the optical power of the M drive currents;

[0094] Step S2-3: Control the circuit 107 to load drive currents IQ[1~M] onto the laser chip (101) respectively, set the simulated temperatures to ST and ST1, and set the angle to ANG + 5°. Under M drive current conditions, measure and record the optical power of the M drive currents;

[0095] Step S2-4: After completing the optical power test, control the computer 7 to read the number of optical power data points A1 at the ANG angle, the number of optical power data points A2 at the ANG + 5° angle, the optical power distribution data P_A1[1~M][1~A1] at the ANG angle, and the optical power distribution data P_A2[1~M][1~A2] at the ANG + 5° angle;

[0096] The function of the angle +5° is to cause the angle to shift, so that resonance cannot occur, and thus no feedback is generated.

[0097] Step S2-5: Analyze P_A1[1~M][1~A1] and P_A2[1~M][1~A2] to obtain the distribution traces PI_A1 (with feedback) and PI_A2 (without feedback) of the sample gain chip power varying with the injection current, the threshold current I_th, and the optimal operating current I_lm.

[0098] The method flow for feature extraction of the distribution trace of the sample gain chip power varying with the injection current is to quickly analyze two sets of optical power distribution data to obtain the threshold current I_th and the optimal operating current I_lm. The specific steps are as follows:

[0099] 1) Read the optical power distribution data P_A1[1~M][1~A1] and P_A2[1~M][1~A2];

[0100] 2) Perform point-by-point difference operation on the optical power distribution data of P_A1[1~A1] and P_A2[1~A2] measured under the drive current IQ[1~M]. The optical power distribution data is transformed into difference distribution data D_P, and the distribution traces PI_A1 (with feedback) and PI_A2 (without feedback) of the sample gain chip power varying with the injection current are plotted.

[0101] 3) Find the first drive current value IQ[TH_1] for which the difference distribution data D_P > THR_1 (THR_1 = 1 mW) holds. Set the threshold current I_th = IQ[TH_1], and determine whether D_P[1~TH_1] > 0 holds. If it holds, continue with the following steps; otherwise, return and output that the sample gain chip is unqualified.

[0102] 4) Calculate the slope K between adjacent points within the drive current IQ[TH_1~M] range of the PI_A2 trace to find IQ[TH_2] that satisfies the following formula:

[0103] K < THR_2 (THR_2 = ((P_A2[TH_1 - 1][i] - P_A2[TH_1 - 2][i - 1]) / (IQ[2] - IQ[1])))

[0104] Output the optimal operating current I_lm = IQ[TH_2], and save the I_1 drive currents between IQ[TH_1] and IQ[TH_2] in the drive current I_dc.

[0105] 5) Store the sample gain chip threshold current I_th in STC[I_th] and the optimal operating current I_lm in STC[I_lm].

[0106] Perform optical wavelength tests on the sample gain chip in sequence. The specific steps are as follows:

[0107] Step S2 - 6: Control the computer 7 to remotely start the optical switch 3 and place it in the channel position CP[2].

[0108] Step S2 - 7: Control the circuit 107 to load the drive currents I_dc[1~I_1] onto the laser chip (101) respectively, load the actuation signals STEP[1~S1] onto the actuator (105) respectively, set the analog temperature to ST and ST1, and set the angle to ANG. Measure and record the data of the resonant wavelengths of [I_1][S1] cavity lengths under the I_1 drive current conditions.

[0109] Step S2 - 8: After completing the optical wavelength test, control the computer 7 to read the number of optical wavelength data points S1, the number of power points P1, the number of drive current data points I_1, and the optical wavelength distribution data WA_D[1~S1][1~P1][1~I_1].

[0110] Step S2-9: Analyze WA_D[1~S1][1~P1][1~I_1] to obtain the distribution trace W_I of the lasing wavelength of the sample gain chip with respect to the threshold current and the resonance scanning range W_R.

[0111] The method flow for feature extraction of the distribution trace of the lasing wavelength of the sample gain chip with respect to the threshold current, by quickly analyzing the optical wavelength distribution data, thereby obtaining the resonance scanning range W_R, the specific steps are as follows:

[0112] 1) Read the resonance optical wavelength distribution data WA_D[1~S1][1~P1][1~I_1] and the optimal operating current IQ[TH_2] in STC[CP[1]];

[0113] 2) Plot the distribution trace W_I of the lasing wavelength of the sample gain chip with respect to the threshold current, and find the wavelength value WA_MAX[I_dc[1~I_1]] corresponding to the maximum optical power recorded in the original optical wavelength distribution data under the condition of the driving current I_dc[1~I_1];

[0114] 3) Locate the first lasing center wavelength point POS[1] operating at the threshold current point according to WA_MAX[I_dc[1]];

[0115] 4) Starting from POS[1], progressively search for the lasing center wavelength points POS[2~I_1] of WA_MAX[I_dc[2~I_1]] that deviate from the threshold current point;

[0116] 5) Calculate the corresponding resonance center wavelength range FL_1 between the two wavelength points of POS[1] and MAX[POS[2~I_1]];

[0117] 6) Find the minimum wavelength value WA_D_S and the maximum wavelength value WA_D_E recorded in the original optical wavelength distribution data automatically measured under the condition of the driving current IQ[TH_2]:

[0118] WA_D_S = MIN[WA_D[1~S1]] and WA_D_E = MAX[WA_D[1~S1]]

[0119] 7) Calculate the corresponding resonance scanning range W_R between the two wavelength points of WA_D_S and WA_D_E;

[0120] 8) Judge whether W_R > THR_3 (THR_3 = FL_1 + 80nm) holds. If it holds, store the resonance scanning range W_R of the sample gain chip in STC[W_R]. If it does not hold, return and output that the sample gain chip is unqualified;

[0121] Step S2-10: Control the computer 7 to remotely start the optical switch 3 to the channel position CP[3];

[0122] Step S2-11: Control the circuit 107 to load a driving current I_th + 300 mA to the laser chip (101), set the analog temperature to ST and ST1, and set the angles to ANG[1~G1]. Under these conditions, measure and record the data of the amplified spontaneous emission spectrum;

[0123] Step S2-12: After completing the amplified spontaneous emission spectrum test, control the computer 7 to read the number of optical wavelength data points S2, the number of power points P2, and the number of angle points G1, and the amplified spontaneous emission spectrum distribution data ASE[1~S2][1~P2][1~G1];

[0124] Step S2-13: Analyze ASE[1~S2][1~P2][1~G1] to obtain the 3dB bandwidth BW_1, spectral ripple RIP_1, and beam emission angle ANG_1 of the sample gain chip;

[0125] The calculation process for analyzing the amplified spontaneous emission spectrum distribution data to obtain the 3dB bandwidth, spectral ripple, and beam emission angle parameters of the sample gain chip is as follows. The specific steps are as follows:

[0126] 1) Read the original amplified spontaneous emission spectrum distribution data ASE[1~S2][1~P2][1~G1], wavelength resolution OR, and WA_D_S and WA_D_E in STC[CP[2]];

[0127] 2) Find the optical power ASE_C[1~G1] corresponding to the lasing center wavelength W_C = ((WA_D_E - WA_D_S) / 2) in ASE[1~S2][1~P2][1~G1];

[0128] 3) Calculate the beam emission angle corresponding to MAX(ASE_C[1~G1]);

[0129] 4) Find the optical power ASE_C[ANG_1] corresponding to W_C in ASE[1~S2][1~P2][ANG_1];

[0130] 5) Calculate the wavelength values W_C_L and W_C_R on both sides of W_C corresponding to when ASE_C[ANG_1] drops to ASE_C[ANG_1] / 2;

[0131] 6) Determine whether (W_C_R - W_C_L) < THR_4 (THR_4 = FL_1 + 60 nm) holds. If it holds, continue; if not, return and output that the sample gain chip is unqualified;

[0132] 7) Search for the optical power P_O corresponding to [W_C - 10*OR ~ W_C + 10*OR] in ASE[1~S2][1~P2][ANG_1 + 5°];

[0133] 8) Calculate the power difference D_P between two adjacent points of P_O, and determine whether 10*log10(ABS(D_P)) < 0.4 dB holds. If it holds, output the test parameters STC[CP[3]] of the sample gain chip; otherwise, return and output that the sample gain chip is unqualified.

[0134] Step S3: Analyze the optical power parameter data, optical wavelength parameter data, and amplified spontaneous emission spectrum data to determine whether the sample gain chip is qualified, and obtain the gain chip parameters and test results.

[0135] During the test process of step S2, it is possible to determine whether the sample gain chip is qualified, or first perform the test, record the test data, and finally determine whether it is qualified based on the test data. Generally speaking, there are four situations regarding whether it is qualified:

[0136] If the power difference between two corresponding points below the threshold current in the optical power difference distribution data is less than a preset power value, it is unqualified;

[0137] If the resonance scanning range is less than or equal to the preset resonance center wavelength range, it is unqualified;

[0138] If the absolute value of the power difference between two adjacent points in the amplified spontaneous emission spectrum distribution data is greater than or equal to a preset power value, it is unqualified;

[0139] If all the above three situations are satisfied simultaneously, it is qualified.

[0140] Embodiment 2

[0141] This embodiment discloses an automatic test system for gain chip parameters based on LM-TL;

[0142] As Figure 4 shown, an automatic test system for gain chip parameters based on LM-TL includes a test preparation module, a test implementation module, and a data analysis module;

[0143] The test preparation module is configured to: connect the sample gain chip to a Littman-Metcalf type tunable laser, set the test parameters, and make preparations before the test;

[0144] The test implementation module is configured to: sequentially perform an optical power test, an optical wavelength test, and an amplified spontaneous emission spectrum test on the sample gain chip to obtain optical power parameter data, optical wavelength parameter data, and amplified spontaneous emission spectrum data;

[0145] The data analysis module is configured to analyze the optical power parameter data, the optical wavelength parameter data, and the amplified spontaneous emission spectrum data, determine whether the sample gain chip is qualified, and obtain the gain chip parameters and the test results.

[0146] Embodiment III

[0147] The purpose of this embodiment is to provide a computer-readable storage medium.

[0148] A computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, it implements the steps in a method for automatically testing gain chip parameters based on LM-TL as described in Embodiment 1 of the present disclosure.

[0149] Embodiment IV

[0150] The purpose of this embodiment is to provide an electronic device.

[0151] An electronic device includes a memory, a processor, and a program stored on the memory and executable on the processor. When the processor executes the program, it implements the steps in a method for automatically testing gain chip parameters based on LM-TL as described in Embodiment 1 of the present disclosure.

[0152] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An automatic test method for gain chip parameters based on LM-TL, characterized in that Including: Connect the sample gain chip to a Littman-Metcalf type tunable laser, set the test parameters, and make preparations before testing; The Littman-Metcalf type tunable laser consists of a sample gain chip, a beam shaping lens, an optical frequency selection element, a tunable mirror, an actuator, a support plate, a control circuit, and an angle adjustment mechanism. The specific composition is as follows: The sample gain chip is an InP-based single-faceted semiconductor gain chip with a semi-butterfly package, used for generating a free-space optical external cavity strong feedback seed source; The beam shaping lens is used for expanding and collimating the laser beam output by the sample gain chip, and is a molded aspherical lens; The optical frequency selection element is a liquid crystal cell, a tunable filter, and a fixed grid filter, and is a blazed grating with a high line density, used for selecting resonant modes; The tunable mirror is used to realize the oscillation of photons with a specific frequency selected by the optical frequency selection element in the external cavity, and is a gold-plated mirror; The actuator is used to precisely adjust the spatial position of the tunable mirror and is driven by the control circuit; The support plate is integrated with a semiconductor cooler and a temperature sensor, used to stabilize the operating temperature of the Littman-Metcalf type tunable laser and is controlled by the control circuit; The control circuit is controlled by a control computer, loading the drive current of the sample gain chip, loading the actuation voltage of the actuator, precisely adjusting the temperature field of the support plate, and loading the drive signal of the angle adjustment mechanism; The angle adjustment mechanism is driven by the control circuit to switch the beam output angle of the measured sample gain chip; Perform optical power test, optical wavelength test, and amplified spontaneous emission spectrum test on the sample gain chip in sequence to obtain optical power parameter data, optical wavelength parameter data, and amplified spontaneous emission spectrum data; Analyze the optical power parameter data, optical wavelength parameter data, and amplified spontaneous emission spectrum data to determine whether the sample gain chip is qualified, and obtain the gain chip parameters and test results.

2. The automatic test method for gain chip parameters based on LM-TL according to claim 1, wherein The preparations before testing are specifically as follows: Connect the sample gain chip to a Littman-Metcalf type tunable laser; Start the Littman-Metcalf type tunable laser; Read the drive current parameter of the control circuit driving the sample gain chip, the spatial position parameter of the actuator, the temperature parameter of the support plate, the angle of the angle adjustment mechanism, and the channel position of the optical switch; Check the connection status of the sample gain chip; Start the high-precision constant temperature box and read the temperature value of the high-precision constant temperature box; Set the test parameters, including the simulated temperature of the high-precision constant temperature box, the sampling rate of the optical power meter, the wavelength resolution of the optical wavelength meter, the wavelength resolution of the spectrometer, multiple drive currents arranged at equal intervals from small to large of the sample gain chip, the simulated temperature of the support plate, and the angle of the angle adjustment mechanism.

3. The automatic test method for gain chip parameters based on LM-TL according to claim 2, characterized in that The specific steps of the optical power test are as follows: Place the optical switch at the channel position for optical power test; According to the set test parameters, control the simulated temperature of the high-precision constant temperature box, the simulated temperature of the support plate, and the angle of the angle adjustment mechanism, respectively load multiple different drive currents on the sample gain chip, and record the optical power data under different drive currents to obtain a set of optical power distribution data; Increase the angle of the angle adjustment mechanism by 5°, and re-measure a set of optical power distribution data; Analyze the two sets of optical power distribution data to obtain the optical power parameter data of the sample gain chip, including the power variation distribution trace with the injection current, the threshold current, and the optimal operating current.

4. The automatic test method for the gain chip parameters based on LM-TL according to claim 3, wherein, Perform a difference operation on the corresponding points of the two sets of optical power distribution data to obtain a set of difference distribution data, and draw the power variation distribution trace with the injection current according to the difference distribution data; In a set of difference distribution data, the first drive current value at which the difference distribution data is greater than the pre-set optical power value is the threshold current; Calculate the slope between adjacent two points in the second set of optical power distribution data to obtain a set of slope values, and the drive current value with the smallest slope is the optimal operating current.

5. The automatic test method for gain chip parameters based on LM-TL according to claim 3, characterized in that, The specific steps for the optical wavelength test are as follows: Place the optical switch at the channel position for the optical wavelength test; According to the set test parameters and the threshold current obtained in the optical power test, control the simulated temperature of the high-precision constant temperature chamber, the simulated temperature of the support plate, and the angle of the angle adjustment mechanism, and apply drive currents higher than the threshold current obtained in the optical power test to the sample gain chip respectively, and record the resonant wavelength data at different drive currents to obtain the optical wavelength distribution data; Analyze the optical wavelength distribution data to obtain the optical wavelength parameter data of the sample gain chip, including the distribution trace of the lasing wavelength with the drive current and the resonant scanning range.

6. The automatic test method for gain chip parameters based on LM-TL according to claim 3, characterized in that The specific steps for the amplified spontaneous emission spectrum test are as follows: Place the optical switch at the channel position for the amplified spontaneous emission spectrum test; According to the set test parameters and the threshold current obtained in the optical power test, control the simulated temperature of the high-precision constant temperature chamber, the simulated temperature of the support plate, and the angle of the angle adjustment mechanism, and apply specified currents to the sample gain chip respectively, and record the amplified spontaneous emission spectrum data at the specified currents to obtain the amplified spontaneous emission spectrum distribution data, where the specified current is the threshold current plus a specified offset; Analyze the amplified spontaneous emission spectrum distribution data to obtain the amplified spontaneous emission spectrum parameter data of the sample gain chip, including the bandwidth, spectral ripple, and beam exit angle.

7. The automatic test method for gain chip parameters based on LM-TL according to claim 1, characterized in that The determination of whether the sample gain chip is qualified includes four cases: If the power difference between the corresponding two points below the threshold current in the optical power difference distribution data is less than the pre-set power value, it is unqualified; If the resonant scanning range is less than or equal to the pre-set resonant center wavelength range, it is unqualified; If the absolute value of the power difference between adjacent two points in the amplified spontaneous emission spectrum distribution data is greater than or equal to the pre-set power value, it is unqualified; If all of the above three cases are satisfied at the same time, it is qualified.

8. An automatic test system for gain chip parameters based on LM-TL, characterized in that, It includes a test preparation module, a test implementation module, and a data analysis module; The test preparation module is configured to: connect the sample gain chip to a Littman-Metcalf type tunable laser, set the test parameters, and make preparations before the test; the Littman-Metcalf type tunable laser consists of a sample gain chip, a beam shaping lens, an optical frequency selection element, a tunable mirror, an actuator, a support plate, a control circuit, and an angle adjustment mechanism part, and the specific composition is as follows: The sample gain chip is an InP-based single-faceted semiconductor gain chip with a semi-butterfly package, and is used for the generation of a free-space optical external cavity strong feedback seed source; The beam shaping lens is used for beam expansion and collimation of the laser beam output by the sample gain chip, and is a molded aspherical lens; The optical frequency selection element is a liquid crystal cell, a tunable filter, and a fixed grid filter, and is a blazed grating with a high line density, and is used for the selection of resonant modes; The tunable mirror is used to realize the oscillation of photons with a specific frequency selected by the optical frequency selection element in the external cavity, and is a gold-plated mirror; The actuator is used to precisely adjust the spatial position of the tunable mirror and is driven by a control circuit; The support plate is integrated with a semiconductor cooler and a temperature sensor, and is used to stabilize the operating temperature of the Littman-Metcalf type tunable laser and is controlled by a control circuit; The control circuit is controlled by a control computer, and is used for loading the drive current of the sample gain chip, loading the actuation voltage of the actuator, precisely adjusting the temperature field of the support plate, and loading the drive signal of the angle adjustment mechanism; The angle adjustment mechanism is driven by the control circuit to switch the beam emission angle of the measured sample gain chip; The test implementation module is configured to: sequentially perform optical power test, optical wavelength test, and amplified spontaneous emission spectrum test on the sample gain chip to obtain optical power parameter data, optical wavelength parameter data, and amplified spontaneous emission spectrum data; The data analysis module is configured to: analyze the optical power parameter data, optical wavelength parameter data, and amplified spontaneous emission spectrum data to determine whether the sample gain chip is qualified, and obtain the gain chip parameters and test results.

9. A computer-readable storage medium having a program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps in a method for automatically testing gain chip parameters based on LM-TL as described in any one of claims 1-7.

10. An electronic device, comprising a memory, a processor, and a program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps in a method for automatically testing gain chip parameters based on LM-TL as described in any one of claims 1-7.

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