VCSEL laser calibration method and system applied to fiber bragg grating sensing

Abstract

The invention provides a VCSEL laser calibration method and system applied to fiber bragg grating sensing, and relates to the technical field of fiber bragg grating demodulation.The method comprises the steps that multiple voltage and current parameter sets in the calibration system are collected, and output parameters corresponding to the voltage and current parameter sets are calculated to construct a simplified output corresponding table; according to the simplified output corresponding table, a tuning characteristic curve corresponding to the VCSEL is obtained, and the tuning characteristic curve comprises a wavelength current tuning characteristic curve and a wavelength voltage tuning characteristic curve; intercepting wavelength voltage tuning characteristic curves under different currents and splicing the wavelength voltage tuning characteristic curves to obtain a spliced wavelength voltage and current tuning curve; and calculating a voltage and current parameter and a voltage change derivative corresponding to the spliced wavelength voltage and current tuning curve at a preset wavelength interval, and constructing a laser wavelength lookup table according to the voltage and current parameter and the voltage change derivative so as to calibrate laser output by the VCSEL. According to the invention, the accuracy and robustness of laser calibration can be improved.

Description

Technical Field

[0001] This invention relates to the field of fiber grating demodulation technology, and in particular to a VCSEL laser calibration method and system applied to fiber grating sensing. Background Technology

[0002] VCSEL lasers possess advantages such as low power consumption, low cost, and ease of integration, leading to their widespread application in optical sensing, data communication, and lighting displays. In recent years, wavelength-tunable VCSEL lasers have been developed and applied in fiber grating sensing and optical coherence tomography (OCT) diagnostics, improving the overall performance of traditional technologies. Taking fiber grating sensing as an example, using VCSEL lasers as the light source can reduce system size, power consumption, and cost, potentially driving the industrial application of fiber grating sensing technology.

[0003] Chinese Patent Publication No. CN110333049A discloses a semiconductor laser calibration method based on fiber optic sensing. The method includes: establishing an accurate correspondence between the laser output optical signal and the laser drive current by calibrating the center wavelength of the narrowband optical pulses output by the laser. Based on this correspondence, the present invention can complete the calibration of the laser output optical signal of the fiber optic demodulation system in a high-speed digital signal processing chip or a large-scale programmable logic array chip, or in host computer software. However, the above scheme does not consider the influence of the drive voltage on the wavelength and output power, and cannot construct a multi-dimensional data correspondence, thus limiting its application scope and robustness. Therefore, it is essential to provide a VCSEL laser calibration method and system applied to fiber optic grating sensing to improve the accuracy and robustness of laser calibration. Summary of the Invention

[0004] In view of this, the present invention proposes a VCSEL laser calibration method and system for fiber optic grating sensing. By sampling multiple sets of voltage and current and calculating the corresponding output wavelength and output power, the amount of data storage and processing is greatly reduced. The spliced ​​curve avoids the breakage or nonlinear abrupt change of the tuning wavelength under a single current range, improves the linearity and usable range of the entire spectrum, and further enhances the accuracy and robustness of laser calibration.

[0005] This invention provides a method for calibrating a VCSEL laser used in fiber Bragg grating sensing, the method comprising: Multiple sets of voltage and current parameters are collected in the calibration system, and the output parameters corresponding to the voltage and current parameter sets are calculated to construct a simplified output correspondence table. The output parameters include the output wavelength and output power of the VCSEL laser. According to the simplified output correspondence table, the tuning characteristic curve corresponding to the VCSEL laser is obtained, wherein the tuning characteristic curve includes the wavelength current tuning characteristic curve and the wavelength voltage tuning characteristic curve. The wavelength-voltage tuning characteristic curves under different currents are extracted and spliced ​​together to obtain the spliced ​​wavelength-voltage-current tuning curve. The voltage and current parameters and voltage change derivatives corresponding to the spliced ​​wavelength voltage and current tuning curve are calculated with a preset wavelength interval, and a laser wavelength lookup table is constructed based on the voltage and current parameters and the voltage change derivatives to calibrate the laser output by the VCSEL laser.

[0006] Based on the above technical solutions, preferably, the multiple sets of voltage and current parameters in the acquisition and calibration system specifically include: The current parameters in the voltage and current parameter group are selected at a first interval between the current threshold and the current upper limit, and the voltage parameters in the voltage and current parameter group are selected at a second interval within the voltage tuning range. The corresponding current parameters and voltage parameters are then combined to obtain the voltage and current parameter group.

[0007] Based on the above technical solutions, preferably, the step of obtaining the tuning characteristic curve of the VCSEL laser according to the simplified output correspondence table specifically includes: Based on the simplified output correspondence table showing the mapping relationship between output wavelength and current under a fixed voltage, a quadratic function is fitted using the least squares method to obtain the wavelength-current tuning characteristic curve and the corresponding wavelength-current tuning characteristic curve function. Based on the simplified output correspondence table, the mapping relationship between output wavelength and voltage under fixed current is obtained. A quadratic function is fitted using the least squares method to obtain the wavelength-voltage tuning characteristic curve and the wavelength-voltage tuning characteristic curve function corresponding to the wavelength-voltage tuning characteristic curve.

[0008] More preferably, the step of stitching together the wavelength-voltage tuning characteristic curves under different currents specifically includes: The voltage tuning characteristic curves of each wavelength are cut with a preset start wavelength, a preset segmentation wavelength, and a preset end wavelength. The first wavelength segment and the second wavelength segment in the first power stage of each wavelength voltage tuning characteristic curve are compared. If the current of the first wavelength segment is less than the current of the second wavelength segment, the first wavelength segment is replaced by the second wavelength segment.

[0009] More preferably, the step of stitching together the wavelength-voltage tuning characteristic curves under different currents further includes: The third and fourth wavelength segments in the second power stage of the voltage tuning characteristic curves of each wavelength are compared. If the current in the third wavelength segment is less than the current in the fourth wavelength segment, the fourth wavelength segment is replaced by the third wavelength segment. The laser power in the second power stage is greater than the laser power in the first power stage.

[0010] More preferably, the preset start wavelength, the preset segmentation wavelength, and the preset end wavelength are determined by the actual application band requirements of the VCSEL laser, and different wavelength segments in all wavelength voltage tuning characteristic curves are spliced ​​sequentially along the wavelength increasing direction.

[0011] More preferably, the step of constructing a laser wavelength lookup table based on the voltage and current parameters and the derivative of the voltage change specifically includes: Calculate the voltage and current parameters and voltage change derivatives corresponding to the spliced ​​wavelength voltage and current tuning curves at preset wavelength intervals, and construct an initial wavelength lookup table; Based on the simplified output correspondence table, the wavelength deviation corresponding to each voltage and current parameter is output. If the wavelength deviation is greater than the preset deviation threshold, the voltage value is adjusted according to the voltage change derivative until all wavelength deviations are lower than the preset deviation threshold, so as to obtain the laser wavelength lookup table.

[0012] A second aspect of this application provides a VCSEL laser calibration system for fiber optic grating sensing, the VCSEL laser calibration system comprising a data acquisition module, a curve stitching module, and a laser calibration module, wherein... The data acquisition module is used to acquire multiple sets of voltage and current parameters in the calibration system and calculate the output parameters corresponding to the voltage and current parameter sets to construct a simplified output correspondence table. The output parameters include the output wavelength and output power of the VCSEL laser. The curve splicing module is used to obtain the tuning characteristic curve corresponding to the VCSEL laser according to the simplified output correspondence table. The tuning characteristic curve includes the wavelength current tuning characteristic curve and the wavelength voltage tuning characteristic curve. The wavelength voltage tuning characteristic curves under different currents are spliced ​​to obtain the spliced ​​wavelength voltage current tuning curve. The laser calibration module is used to calculate the voltage and current parameters and voltage change derivatives corresponding to the spliced ​​wavelength voltage and current tuning curve at preset wavelength intervals, and to construct a laser wavelength lookup table based on the voltage and current parameters and the voltage change derivatives to calibrate the laser output by the VCSEL laser.

[0013] A third aspect of this application provides an electronic device including a processor, a memory, a user interface, and a network interface, wherein the memory is used to store instructions, the user interface and the network interface are used to communicate with other devices, and the processor is used to execute the instructions stored in the memory.

[0014] A fourth aspect of this application provides a computer-readable storage medium having a computer program stored thereon, the computer program being executed by a processor to implement the steps of a VCSEL laser calibration method applied to fiber optic grating sensing.

[0015] The VCSEL laser calibration method and system for fiber Bragg grating sensing provided by this invention has the following advantages over the prior art: (1) By sampling multiple sets of voltage / current and calculating the corresponding output wavelength and output power, the original continuous tuning data can be condensed into a simplified output correspondence table, which greatly reduces the amount of data storage and processing. The wavelength voltage curves under different bias currents are extracted and spliced ​​at the overlapping bands, realizing continuous and smooth tuning characteristics in a wider wavelength range. The spliced ​​curves avoid the breakage or nonlinear change of the tuning wavelength under a single current range, improving the linearity and usable range of the entire spectrum. At the same time, by cross-validating the consistency of the tuning curves under different current conditions and removing abnormal points during the splicing process, the non-ideal effects caused by temperature drift, driving circuit noise, etc. can be suppressed. The output wavelength lookup table has its own voltage change derivative information, which can be used for dynamic compensation and closed-loop correction, further improving the accuracy and robustness of laser calibration.

[0016] (2) By comparing two current curve segments in the same wavelength range in the first power stage and the second power stage respectively, the segment with lower current is selected, which directly reduces the laser driving current. Local replacement of each curve segment can eliminate discontinuous abrupt changes or reverse jumps caused by power stage conversion, ensuring a smooth transition of wavelength and current relationship in the low-to-high power switching range. The smooth and continuous tuning curve can avoid abrupt noise in output power and wavelength, improve system stability and signal quality. The replaced spliced ​​tuning curve takes into account the best driving conditions of each power stage, so that the entire preset wavelength range can obtain the required output at a lower current. The optimized tuning range is wider, maximizing the available wavelength range of the device and meeting the requirements of large dynamic scanning. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic flowchart illustrating a VCSEL laser calibration method for fiber optic grating sensing provided by the present invention; Figure 2 A schematic diagram of the frame of a VCSEL laser wavelength calibration device provided by the present invention; Figure 3 This is a schematic diagram of the structure of the real-time task scheduling system provided by the present invention; Figure 4 This is a schematic diagram of the structure of the electronic device provided by the present invention.

[0019] Explanation of reference numerals in the attached figures: 1. VCSEL laser calibration system; 11. Data acquisition module; 12. Curve splicing module; 13. Laser calibration module; 2. Electronic equipment; 21. Processor; 22. Communication bus; 23. User interface; 24. Network interface; 25. Memory. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] This invention discloses a VCSEL laser calibration method for fiber optic grating sensing, with reference to... Figure 1 The steps of this method include S1 to S4.

[0022] Step S1: Collect multiple sets of voltage and current parameters in the calibration system and calculate the output parameters corresponding to the voltage and current parameter sets to construct a simplified output correspondence table. The output parameters include the output wavelength and output power of the VCSEL laser.

[0023] In this step, the current parameters in the voltage and current parameter group are selected at a first interval between the current threshold and the current upper limit, and the voltage parameters in the voltage and current parameter group are selected at a second interval within the voltage tuning range. The corresponding current parameters and voltage parameters are then combined to obtain the voltage and current parameter group.

[0024] Furthermore, the driving current of a VCSEL laser has a threshold I0 and an upper limit I1. After the driving current reaches the threshold, the laser begins to output an optical signal. The wavelength and power of the output optical signal are affected by three factors: temperature, voltage, and current. Precise control of the laser output can be achieved by constructing an output correspondence table. Therefore, a simplified output correspondence table is constructed to record the laser output characteristics. The simplified output correspondence table consists of multiple sets of data, each containing voltage and current values ​​along with the corresponding laser output wavelength and power. When selecting voltage and current parameter sets to construct the simplified output correspondence table, the current is selected based on the laser output current threshold I0. a With upper limit I b Inner intervals D I The selected voltage mode is within the tuning range [V]. a V b Equal intervals within D v Select voltage values. Combine the selected voltage and current values ​​in pairs as measurement parameter groups, measure and record the actual output power and wavelength of the laser under each parameter group, and obtain a simplified output correspondence table.

[0025] Step S2: Obtain the tuning characteristic curve corresponding to the VCSEL laser according to the simplified output correspondence table. The tuning characteristic curve includes the wavelength current tuning characteristic curve and the wavelength voltage tuning characteristic curve.

[0026] This step also includes steps S21 to S22.

[0027] Step S21: Based on the simplified output correspondence table, the mapping relationship between the output wavelength and current under a fixed voltage is obtained by performing quadratic function fitting using the least squares method to obtain the wavelength current tuning characteristic curve and the wavelength current tuning characteristic curve function corresponding to the wavelength current tuning characteristic curve.

[0028] Step S22: Based on the simplified output correspondence table, the mapping relationship between the output wavelength and voltage under a fixed current is obtained by performing quadratic function fitting using the least squares method to obtain the wavelength-voltage tuning characteristic curve and the wavelength-voltage tuning characteristic curve function corresponding to the wavelength-voltage tuning characteristic curve.

[0029] Furthermore, under constant temperature and voltage conditions, the output wavelength of a VCSEL laser exhibits a quadratic curve relationship with the input current, and the coefficients of the curve expression are related to the voltage. Similarly, when the current is constant, the output wavelength also exhibits a quadratic curve relationship with the voltage, and the coefficients of the curve expression are related to the current. Therefore, the simplified output correspondence table data is grouped according to voltage parameter values, with each group having the same voltage value. For each group, the coefficients of the curve expression are calculated using the least squares method, thus obtaining the tuning characteristic curve function expression of the output wavelength as a function of current under a fixed voltage. Based on the obtained wavelength-current tuning characteristic curve function expression, the output wavelength corresponding to any current under a fixed voltage can be calculated. Using a uniform value selection method, the wavelength can be much smaller than D. I Current interval D I2 Select a current value and calculate the output wavelength corresponding to the selected current value under each fixed voltage. Add the calculation results to the simplified output correspondence table. Group the data in the supplemented simplified output correspondence table according to the current value, calculate the wavelength-voltage variation curve expression for each group of data, and obtain the wavelength-voltage tuning characteristic curve function expression.

[0030] Under constant temperature conditions, the output power of a VCSEL laser exhibits an approximate quadratic curve relationship with both input voltage and input current when the current and voltage are constant. Therefore, similar to the calculation process for the wavelength-voltage tuning curve and wavelength-current tuning curve, the power-voltage curve and power-current tuning characteristic curve can be calculated from simplified output data tables.

[0031] In this step, the quadratic function naturally possesses curvature, which can accurately characterize the nonlinear tuning characteristics of VCSEL near the threshold and in the high bias region. Least square fitting automatically smooths discrete measurement noise by co-fitting the entire set of data, achieving a more stable and continuous tuning curve. During the fitting process, all sampling points are integrated, and occasional outliers and random noise are automatically filtered out, which is more robust than point-by-point table lookup.

[0032] Step S3: Extract wavelength-voltage tuning characteristic curves under different currents and splice them together to obtain spliced ​​wavelength-voltage-current tuning curves.

[0033] This step also includes steps S31 to S32.

[0034] Step S31: Cut the voltage tuning characteristic curve of each wavelength with a preset start wavelength, a preset segmentation wavelength and a preset end wavelength. Compare the first wavelength segment and the second wavelength segment in the first power stage of each wavelength voltage tuning characteristic curve. If the current of the first wavelength segment is less than the current of the second wavelength segment, then replace the first wavelength segment with the second wavelength segment.

[0035] In this step, the preset start wavelength, preset segmentation wavelength, and preset end wavelength are determined by the actual application band requirements of the VCSEL laser, and different wavelength segments in all wavelength voltage tuning characteristic curves are spliced ​​sequentially along the wavelength increasing direction.

[0036] Step S32: Compare the third and fourth wavelength segments in the second power stage of the voltage tuning characteristic curves of each wavelength. If the current in the third wavelength segment is less than the current in the fourth wavelength segment, then replace the fourth wavelength segment with the third wavelength segment. The laser power in the second power stage is greater than the laser power in the first power stage.

[0037] Furthermore, since the effect of voltage change on laser output power is about one-tenth that of current change, and the wavelength voltage tuning curve has a wider wavelength range, this invention uses voltage regulation to control the adjustment of the output wavelength and current regulation to control the adjustment of the output power. By splicing the wavelength voltage tuning curves when different currents are fixed, a flatter output power wavelength curve and a smoother wavelength voltage current tuning curve are obtained.

[0038] The laser tuning characteristic curve is selected from the portion where the output power changes relatively flat with voltage at a fixed current. Since the output power ranges of the wavelength voltage tuning curves at different fixed currents overlap, and the output power increases with the input current at a fixed voltage but decreases with the input voltage at a fixed current, for a single wavelength voltage tuning curve at a fixed current, the portion with lower output power is replaced by the wavelength voltage curve at a higher current, and the portion with higher output power is replaced by the wavelength voltage curve at a lower current, thus obtaining the spliced ​​wavelength voltage current tuning curve.

[0039] In this embodiment, two current curve segments within the same wavelength range are compared in the first power stage (low power) and the second power stage (high power), and the segment with the lower current is selected, directly reducing the laser drive current. Local replacement of each curve segment can eliminate discontinuous abrupt changes or reverse jumps caused by power stage transitions, ensuring a smooth transition of the wavelength-current relationship in the low-to-high power switching range. The smooth and continuous tuning curve can avoid abrupt noise in output power and wavelength, improving system stability and signal quality. The replaced spliced ​​tuning curve takes into account the optimal driving conditions of each power stage, enabling the entire preset wavelength range to obtain the required output at a lower current. The optimized tuning range is wider, maximizing the usable wavelength range of the device and meeting the requirements of large dynamic scanning. Through local comparison, high current segments that are severely affected by temperature drift or device nonlinearity in certain wavelength bands are eliminated, reducing the overall fluctuation and error of the tuning curve, improving the monotonicity and robustness of wavelength-current mapping, and facilitating accurate positioning and fast closed-loop control.

[0040] Step S4: Calculate the voltage and current parameters and voltage change derivatives corresponding to the spliced ​​wavelength voltage and current tuning curves with a preset wavelength interval, and construct a laser wavelength lookup table based on the voltage and current parameters and voltage change derivatives to calibrate the laser output by the VCSEL laser.

[0041] This step also includes steps S41 to S42.

[0042] Step S41: Calculate the voltage and current parameters and voltage change derivatives corresponding to the spliced ​​wavelength voltage and current tuning curves with a preset wavelength interval, and construct an initial wavelength lookup table.

[0043] Step S42: Based on the simplified output correspondence table, output the corresponding wavelength deviation for each voltage and current parameter. If the wavelength deviation is greater than the preset deviation threshold, adjust the voltage value according to the voltage change derivative until all wavelength deviations are lower than the preset deviation threshold, so as to obtain the laser wavelength lookup table.

[0044] Based on the spliced ​​wavelength-voltage-current tuning curve, calculate the voltage and current parameters corresponding to the required wavelength and the derivative of wavelength with respect to voltage change. Measure the actual output wavelength under the voltage and current parameters. For points where the error does not meet the requirements, perform voltage correction based on the derivative. For each set of data in the lookup table, perform actual measurements. Subtract the required wavelength value from the actual measured wavelength value to obtain the difference between the actual measured wavelength value and the required wavelength value for that set of parameters. For parameter sets where the wavelength difference does not meet the requirements, perform voltage fine-tuning. Divide the wavelength difference of that set by the derivative of wavelength with respect to voltage change to obtain the voltage correction value. Subtract the voltage correction value from the original voltage parameter to obtain the corrected voltage value. Record the current value, the corrected voltage value, and the laser output wavelength to finally obtain the laser wavelength lookup table.

[0045] In this step, an initial lookup table is directly generated with preset wavelength intervals, quickly covering the entire tuning range. Based on the linear approximation of analytical differentiation, deviation can be significantly reduced with a single iteration, requiring fewer iterations and achieving fast convergence. By relying on the deviation of the actual measurement in the simplified output table, wavelength shifts caused by device nonlinearity, temperature drift, or driving circuit errors can be automatically corrected. Uniform error correction is performed on all lookup points across the entire band, avoiding abrupt changes or error accumulation at splicing points in local bands. The result is a lookup table with uniform and controlled wavelength error across the entire tuning range, meeting the requirements of high-precision fiber Bragg grating sensing. The calibration process can be fully automated, eliminating the need for repeated manual fine-tuning, reducing operational complexity and maintenance costs.

[0046] The present invention also provides a VCSEL laser wavelength calibration device, the specific structure of which is as follows: Figure 2As shown. The device is mainly divided into three parts: a laser driver section, a laser output measurement section, and a data processing section. For the laser driver section, a single FPGA chip is used as the core, receiving commands from the host computer via serial communication. The FPGA chip is connected to a three-channel D / A conversion circuit. The driving voltage adjustment range is [V]. a V b The driving current adjustment range is [I]. a ,I b The selected D / A chip is a 16-bit D / A chip, which can achieve a voltage resolution of (V). b -V a ) / 2 16 and current resolution is (I b -I a ) / 2 16 Precise control is achieved. Two of the three D / A conversion circuits are connected to constant voltage source circuits, and one is connected to a constant current source circuit. One constant voltage source circuit provides the driving voltage for the VCSEL laser, while the other constant voltage source circuit is used to control the temperature of the VCSEL laser. The constant current source circuit provides the driving current for the VCSEL laser.

[0047] The VCSEL laser output measurement section of the VCSEL laser wavelength calibration device uses a wavelength meter, model AQ6151B, for data acquisition. The computer communicates with the wavelength meter via Ethernet. After receiving a command, the computer performs a single measurement and sends the measured center wavelength and power to the computer.

[0048] The specific steps of the VCSEL laser output measurement process are as follows: The computer establishes a communication connection with the wavelength meter and the laser driver; the computer sends the drive parameter setting command to the laser driver through the serial port, and the laser driver outputs the voltage and current values; the computer sends the measurement command to the wavelength meter through the network port, and the wavelength meter performs the measurement after receiving the command and sends the measurement data to the computer through the network port; the computer records the VCSEL laser drive parameters at this time as well as the actual measured VCSEL laser output wavelength and power.

[0049] In one example, the VCSEL laser used has a current threshold I1 of 10mA, a current upper limit I2 of 18mA, and a voltage tuning lower limit V. a The maximum value is 0V, and the upper limit is V. b The voltage is 18V. When performing simplified output correspondence table measurements, the current interval D is... I The current value is 2mA, the number of current values ​​is 5, and the voltage interval is D. VThe voltage was set to 4.5V, with five voltage values, forming a total of 25 measurement parameter groups. The actual output wavelength and power of the laser corresponding to each parameter group were measured sequentially using a VCSEL laser calibration system, resulting in a simplified output correspondence table. Under constant temperature and current conditions, the wavelength of a VCSEL laser exhibits a quadratic relationship with voltage, and the output wavelength also approximately follows a quadratic relationship with current when the voltage is fixed. For a single quadratic function curve, the function expression can be calculated by measuring the values ​​at three points on the curve. Considering factors such as measurement error, five points were selected for measurement to reduce the impact of measurement error.

[0050] The simplified output correspondence table data is divided into five groups based on voltage values. Each group contains five sets of measurement parameters. Based on the current value, output wavelength, and output power of each group, the least squares method is used to calculate the output wavelength-current and output power-current tuning characteristic curves under a fixed voltage. Within the current threshold I1 = 10mA and the current upper limit I2 = 18mA, according to the current interval D... I2 Eighty-one current values, each at equal intervals of 0.1 mA, were selected and substituted into the function expressions for the output wavelength-current and output power-current tuning characteristic curves. The laser output wavelength and power corresponding to each of the 81 selected current values ​​under each curve were calculated. The calculation results were then added to a simplified output correspondence table. Based on whether the current values ​​were identical, the data were divided into 81 groups, each containing 5 parameter groups. Using the voltage value, output wavelength, and output power of each group, the least squares method was used to calculate the function expressions for the output wavelength-voltage and output power-voltage tuning characteristic curves under a fixed current.

[0051] From the tuning characteristic curves obtained above, curves with fixed current values ​​of 16mA, 15mA, and 14mA are selected and spliced ​​together. Taking 1546nm as the starting wavelength, 1549nm and 1552nm as the dividing points, and 1554nm as the ending wavelength, the tuning characteristic curves are cut. For the tuning characteristic curve with a fixed current value of 16mA, the portion with wavelength values ​​of 1546-1549nm is selected; for the tuning characteristic curve with a fixed current value of 15mA, the portion with wavelength values ​​of 1549-1552nm is selected; and for the tuning characteristic curve with a fixed current value of 14mA, the portion with wavelength values ​​of 1552-1554nm is selected. The three curve segments are spliced ​​together in wavelength order to finally obtain a tuning curve with a wavelength tuning range of 8nm, a starting wavelength of 1546nm, and an ending wavelength of 1554nm.

[0052] Based on the spliced ​​curve function expression, the voltage and current values ​​corresponding to each wavelength value are calculated from 1546-1554nm at 0.01nm intervals, and the derivative of the wavelength with respect to voltage at the corresponding point is calculated to obtain an initial wavelength lookup table. Using a VCSEL laser calibration system, each set of parameters in the lookup table is measured and verified sequentially. If the wavelength deviation is less than 10pm, the parameter set is retained and the next set of parameters is measured. If the wavelength deviation is greater than 10pm, the corrected voltage value is calculated based on the derivative of the wavelength with respect to voltage and the wavelength deviation value. Measurements are repeated until the wavelength deviation is less than 10pm before proceeding to the next set of parameters, ultimately obtaining the laser wavelength lookup table. This specific implementation method results in a VCSEL laser wavelength lookup table with fewer wavelength tuning path jump points, a wavelength tuning range of 8nm, and power fluctuations within ±0.5dB for different output wavelengths.

[0053] In this embodiment, by sampling multiple sets of voltage / current and calculating the corresponding output wavelength and output power, the original continuous tuning data can be condensed into a simplified output lookup table, greatly reducing the amount of data storage and processing. Wavelength-voltage curves under different bias currents are extracted and spliced ​​at overlapping bands, achieving continuous and smooth tuning characteristics over a wider wavelength range. Furthermore, the spliced ​​curves avoid breaks or nonlinear abrupt changes in tuning wavelengths under a single current range, improving the linearity and usable range of the entire spectrum. At the same time, by cross-validating the consistency of tuning curves under different current conditions and eliminating outliers during the splicing process, the non-ideal effects caused by temperature drift, drive circuit noise, etc. can be suppressed. The output wavelength lookup table has built-in voltage change derivative information, which can be used for dynamic compensation and closed-loop correction, further improving the accuracy and robustness of laser calibration.

[0054] Based on the above method, this application discloses a VCSEL laser calibration system applied to fiber optic grating sensing, with reference to... Figure 3 The VCSEL laser calibration system 1 includes a data acquisition module 11, a curve stitching module 12, and a laser calibration module 13, wherein... The data acquisition module 11 is used to acquire multiple sets of voltage and current parameters in the calibration system and calculate the output parameters corresponding to the voltage and current parameter sets in order to construct a simplified output correspondence table. The output parameters include the output wavelength and output power of the VCSEL laser. The curve splicing module 12 is used to obtain the tuning characteristic curve corresponding to the VCSEL laser according to the simplified output correspondence table. The tuning characteristic curve includes the wavelength current tuning characteristic curve and the wavelength voltage tuning characteristic curve. The wavelength voltage tuning characteristic curves under different currents are spliced ​​to obtain the spliced ​​wavelength voltage current tuning curve. The laser calibration module 13 is used to calculate the voltage and current parameters and voltage change derivatives corresponding to the spliced ​​wavelength voltage and current tuning curves at preset wavelength intervals, and to construct a laser wavelength lookup table based on the voltage and current parameters and voltage change derivatives to calibrate the laser output by the VCSEL laser.

[0055] In one example, the data acquisition module 11 selects the current parameter in the voltage and current parameter group at a first interval between the current threshold and the current upper limit, and selects the voltage parameter in the voltage and current parameter group at a second interval within the voltage tuning range, and combines the corresponding current parameter and voltage parameter to obtain the voltage and current parameter group.

[0056] In one example, the curve splicing module 12 is used to perform quadratic function fitting using the least squares method based on the mapping relationship between the output wavelength and current under a fixed voltage according to the simplified output correspondence table, so as to obtain the wavelength current tuning characteristic curve and the wavelength current tuning characteristic curve function corresponding to the wavelength current tuning characteristic curve; based on the mapping relationship between the output wavelength and voltage under a fixed current according to the simplified output correspondence table, it performs quadratic function fitting using the least squares method to obtain the wavelength voltage tuning characteristic curve and the wavelength voltage tuning characteristic curve function corresponding to the wavelength voltage tuning characteristic curve.

[0057] In one example, the curve splicing module 12 is used to cut each wavelength voltage tuning characteristic curve with a preset start wavelength, a preset segmentation wavelength and a preset end wavelength, and compare the first wavelength segment and the second wavelength segment in the first power stage of each wavelength voltage tuning characteristic curve. If the current of the first wavelength segment is less than the current of the second wavelength segment, the first wavelength segment is replaced with the second wavelength segment.

[0058] In one example, the curve splicing module 12 is used to compare the third and fourth wavelength segments in the second power stage of the voltage tuning characteristic curves of each wavelength. If the current of the third wavelength segment is less than the current of the fourth wavelength segment, the fourth wavelength segment is replaced with the third wavelength segment. The laser power in the second power stage is greater than the laser power in the first power stage.

[0059] In one example, the preset start wavelength, preset segmentation wavelength, and preset end wavelength are determined by the actual application band requirements of the VCSEL laser, and different wavelength segments in all wavelength voltage tuning characteristic curves are spliced ​​sequentially along the wavelength increasing direction.

[0060] In one example, the laser calibration module 13 is used to calculate the voltage and current parameters and voltage change derivatives corresponding to the spliced ​​wavelength voltage and current tuning curves at preset wavelength intervals, and construct an initial wavelength lookup table; based on the simplified output correspondence table, the corresponding wavelength deviations are output for each voltage and current parameter; if the wavelength deviation is greater than a preset deviation threshold, the voltage value is adjusted according to the voltage change derivative until all wavelength deviations are lower than the preset deviation threshold, so as to obtain the laser wavelength lookup table.

[0061] Please see Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 4 As shown, the electronic device 2 may include: at least one processor 21, at least one network interface 24, user interface 23, memory 25, and at least one communication bus 22.

[0062] The communication bus 22 is used to enable communication between these components.

[0063] The user interface 23 may include a display screen and a camera. Optionally, the user interface 23 may also include a standard wired interface and a wireless interface.

[0064] The network interface 24 may optionally include a standard wired interface or a wireless interface (such as a Wi-Fi interface).

[0065] The processor 21 may include one or more processing cores. The processor 21 connects to various parts of the server using various interfaces and lines, and performs various server functions and processes data by running or executing instructions, programs, code sets, or instruction sets stored in the memory 25, and by calling data stored in the memory 25. Optionally, the processor 21 may be implemented using at least one hardware form of Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), or Programmable Logic Array (PLA). The processor 21 may integrate one or a combination of several of the following: Central Processing Unit (CPU), Graphics Processing Unit (GPU), and modem. The CPU primarily handles the operating system, user interface, and applications; the GPU is responsible for rendering and drawing the content required for display; and the modem handles wireless communication. It is understood that the modem may also not be integrated into the processor 21 and may be implemented as a separate chip.

[0066] The memory 25 may include random access memory (RAM) or read-only memory. Optionally, the memory 25 may include non-transitory computer-readable storage medium. The memory 25 can be used to store instructions, programs, code, code sets, or instruction sets. The memory 25 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as touch function, sound playback function, image playback function, etc.), instructions for implementing the above-described method embodiments, etc.; the data storage area may store data involved in the above-described method embodiments, etc. Optionally, the memory 25 may also be at least one storage device located remotely from the aforementioned processor 21. Figure 4 As shown, the memory 25, which serves as a computer storage medium, may include an operating system, a network communication module, a user interface module, and an application program for a VCSEL laser calibration method applied to fiber optic grating sensing.

[0067] exist Figure 4 In the electronic device 2 shown, the user interface 23 is mainly used to provide an input interface for the user and to obtain the user input data; while the processor 21 can be used to call the application program stored in the memory 25 for a VCSEL laser calibration method applied to fiber optic grating sensing. When executed by one or more processors, the electronic device performs one or more methods as described in the above embodiments.

[0068] A computer-readable storage medium storing instructions that, when executed by one or more processors, cause a computer to perform one or more methods as described in the embodiments above.

[0069] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0070] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0071] In the several embodiments provided in this application, it should be understood that the disclosed apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the shown or discussed mutual couplings or direct couplings or communication connections may be through some service interfaces; indirect couplings or communication connections between apparatuses or units may be electrical or other forms.

[0072] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0073] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0074] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage device (CMD). Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a memory and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned memory includes various media capable of storing program code, such as USB flash drives, portable hard drives, magnetic disks, or optical disks.

[0075] The above are merely exemplary embodiments of this disclosure and should not be construed as limiting the scope of this disclosure. Any equivalent changes and modifications made in accordance with the teachings of this disclosure shall still fall within the scope of this disclosure. Those skilled in the art will readily conceive of other embodiments of this disclosure upon considering the specification and the disclosure of practical truths. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not described in this disclosure.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for calibrating a VCSEL laser used in fiber optic grating sensing, characterized in that, The method includes: Multiple sets of voltage and current parameters are collected in the calibration system, and the output parameters corresponding to the voltage and current parameter sets are calculated to construct a simplified output correspondence table. The output parameters include the output wavelength and output power of the VCSEL laser. According to the simplified output correspondence table, the tuning characteristic curve corresponding to the VCSEL laser is obtained, wherein the tuning characteristic curve includes the wavelength current tuning characteristic curve and the wavelength voltage tuning characteristic curve. The wavelength-voltage tuning characteristic curves under different currents are extracted and spliced ​​together to obtain the spliced ​​wavelength-voltage-current tuning curve. The voltage and current parameters and voltage change derivatives corresponding to the spliced ​​wavelength voltage and current tuning curve are calculated with a preset wavelength interval, and a laser wavelength lookup table is constructed based on the voltage and current parameters and the voltage change derivatives to calibrate the laser output by the VCSEL laser.

2. The VCSEL laser calibration method for fiber optic grating sensing as described in claim 1, characterized in that, The data acquisition and calibration system includes multiple sets of voltage and current parameters, specifically: The current parameters in the voltage and current parameter group are selected at a first interval between the current threshold and the current upper limit, and the voltage parameters in the voltage and current parameter group are selected at a second interval within the voltage tuning range. The corresponding current parameters and voltage parameters are then combined to obtain the voltage and current parameter group.

3. The VCSEL laser calibration method for fiber optic grating sensing as described in claim 1, characterized in that, The step of obtaining the tuning characteristic curve of the VCSEL laser according to the simplified output correspondence table specifically includes: Based on the simplified output correspondence table, the mapping relationship between output wavelength and current under fixed voltage is obtained by performing quadratic function fitting using the least squares method to obtain the wavelength current tuning characteristic curve and the wavelength current tuning characteristic curve function corresponding to the wavelength current tuning characteristic curve. Based on the simplified output correspondence table, the mapping relationship between output wavelength and voltage under fixed current is obtained. A quadratic function is fitted using the least squares method to obtain the wavelength-voltage tuning characteristic curve and the wavelength-voltage tuning characteristic curve function corresponding to the wavelength-voltage tuning characteristic curve.

4. The VCSEL laser calibration method for fiber optic grating sensing as described in claim 1, characterized in that, The process of stitching together wavelength-voltage tuning characteristic curves under different currents specifically includes: The voltage tuning characteristic curves of each wavelength are cut with a preset start wavelength, a preset segmentation wavelength, and a preset end wavelength. The first wavelength segment and the second wavelength segment in the first power stage of each wavelength voltage tuning characteristic curve are compared. If the current of the first wavelength segment is less than the current of the second wavelength segment, the first wavelength segment is replaced by the second wavelength segment.

5. The VCSEL laser calibration method for fiber optic grating sensing as described in claim 4, characterized in that, The method of stitching together wavelength-voltage tuning characteristic curves under different currents also includes: The third and fourth wavelength segments in the second power stage of the voltage tuning characteristic curves of each wavelength are compared. If the current in the third wavelength segment is less than the current in the fourth wavelength segment, the fourth wavelength segment is replaced by the third wavelength segment. The laser power in the second power stage is greater than the laser power in the first power stage.

6. The VCSEL laser calibration method for fiber optic grating sensing as described in claim 4, characterized in that, The preset start wavelength, the preset segmentation wavelength, and the preset end wavelength are determined by the actual application band requirements of the VCSEL laser, and different wavelength segments in all wavelength voltage tuning characteristic curves are spliced ​​sequentially along the wavelength increasing direction.

7. The VCSEL laser calibration method for fiber optic grating sensing as described in claim 1, characterized in that, The step of constructing a laser wavelength lookup table based on the voltage and current parameters and the voltage change derivative specifically includes: Calculate the voltage and current parameters and voltage change derivatives corresponding to the spliced ​​wavelength voltage and current tuning curves at preset wavelength intervals, and construct an initial wavelength lookup table; Based on the simplified output correspondence table, the wavelength deviation corresponding to each voltage and current parameter is output. If the wavelength deviation is greater than the preset deviation threshold, the voltage value is adjusted according to the voltage change derivative until all wavelength deviations are lower than the preset deviation threshold, so as to obtain the laser wavelength lookup table.

8. A VCSEL laser calibration system for fiber optic grating sensing, characterized in that, The VCSEL laser calibration system (1) includes a data acquisition module (11), a curve stitching module (12), and a laser calibration module (13), wherein, The data acquisition module (11) is used to acquire multiple sets of voltage and current parameters in the calibration system and calculate the output parameters corresponding to the voltage and current parameter sets to construct a simplified output correspondence table. The output parameters include the output wavelength and output power of the VCSEL laser. The curve splicing module (12) is used to obtain the tuning characteristic curve corresponding to the VCSEL laser according to the simplified output correspondence table. The tuning characteristic curve includes the wavelength current tuning characteristic curve and the wavelength voltage tuning characteristic curve. The wavelength voltage tuning characteristic curves under different currents are spliced ​​to obtain the spliced ​​wavelength voltage current tuning curve. The laser calibration module (13) is used to calculate the voltage and current parameters and voltage change derivatives corresponding to the spliced ​​wavelength voltage and current tuning curve at a preset wavelength interval, and to construct a laser wavelength lookup table based on the voltage and current parameters and the voltage change derivatives to calibrate the laser output by the VCSEL laser.

9. An electronic device, characterized in that, The device includes a processor (21), a memory (25), a user interface (23), and a network interface (24). The memory (25) is used to store instructions. The user interface (23) and the network interface (24) are used to communicate with other devices. The processor (21) is used to execute the instructions stored in the memory (25) to cause the electronic device (2) to perform the method as described in any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1-7.

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