Method, system, equipment and product for automatically testing current line width of narrow-line-width laser

Abstract

The invention discloses a narrow-linewidth laser current linewidth automatic test method, system, device and product, frequency noise spectrum data of a laser at different injection current positions are collected through a current scanning mode with a preset step length, and the current linewidth of a narrow-linewidth laser is automatically tested based on the frequency noise spectrum data at the different injection current positions. Line width calculation of the laser at different injection current positions is carried out; and finally, according to the integral line widths at different injection currents, analyzing frequency noise spectrum evolution characteristics of the laser under different injection currents by using an automatic inflection point identification algorithm, thereby determining the integral line width of the laser under the optimal working current based on the frequency noise spectrum evolution characteristics. Therefore, a new line width measurement technology is provided, compared with a traditional delay heterodyne method and an improved null beat scheme, long / short laser delay does not need to be carried out, and therefore the problems that environment noise is introduced by long optical fiber delay and weak signals are submerged by system noise due to short optical fiber delay can be avoided, and the measurement precision is improved.

Description

Technical Field

[0001] This invention belongs to the field of laser testing technology, specifically relating to an automatic testing method, system, equipment, and product for the current linewidth of narrow-linewidth lasers. Background Technology

[0002] Laser linewidth, as a core parameter characterizing laser coherence and phase noise, directly affects its application performance in precision measurement. In fiber optic sensing systems, laser linewidth determines the phase noise level of the interference signal, limiting the system's detection sensitivity. In coherent optical communication, linewidth directly affects the bit error rate performance of the modulation signal. Furthermore, in cutting-edge scientific fields such as lidar and gravitational wave detection, sub-hertz ultra-narrow linewidths are fundamental to achieving high-precision detection. Meanwhile, with the development of laser technology, narrow-linewidth lasers have evolved from the kHz level to the Hz level, thus posing unprecedented technical challenges to traditional linewidth measurement methods.

[0003] The time-delay heterodyne method, as the most classic linewidth measurement scheme, works by splitting the laser into two paths. One path passes through a long-delay fiber (typically requiring a delay time exceeding the laser coherence time) and beats the other path. The laser linewidth is then measured by analyzing the spread of the beat spectrum. While this method is structurally simple, it faces significant bottlenecks in sub-kHz linewidth measurement. Theoretically, measuring a 1Hz linewidth requires an fiber length exceeding 100 kilometers. Such a long fiber not only introduces significant environmental disturbance noise but also produces a non-negligible dispersion effect, leading to a sharp decrease in measurement accuracy. Furthermore, research indicates that using a 76km delay fiber... When measuring a 230Hz linewidth fiber laser, the system signal-to-noise ratio has already dropped to a critical state; further reducing the linewidth will lead to measurement failure. Although the improved zero-beat scheme avoids DC noise problems through an acousto-optic frequency shifter, it faces new challenges in sub-Hertz measurements. Specifically, the short fiber delay reduces the phase noise conversion efficiency, causing weak signals to be submerged by system noise. Furthermore, some teams have found that when the delay fiber is shortened to the order of 10 meters, the phase noise component in the electrical signal is too small, and uncorrelated noises such as shot noise, thermal noise, and ADC quantization noise from the photodetector become the dominant factors, leading to serious distortion of the measurement results.

[0004] Therefore, traditional linewidth measurement methods suffer from poor measurement accuracy; thus, how to provide an automatic testing method for the current linewidth of narrow-linewidth lasers with high measurement accuracy has become an urgent problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide an automatic testing method, system, equipment, and product for the current linewidth of narrow-linewidth lasers, in order to solve the problem of low linewidth measurement accuracy in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: Firstly, an automatic method for testing the current linewidth of narrow-linewidth lasers is provided, including: Based on the historical injection current, the injection current supplied to the laser by the programmable current source is adjusted according to a preset step size. After the injection current stabilizes, the output laser of the laser is connected to the laser noise analyzer. The historical injection current is the injection current supplied to the laser by the programmable current source after the last adjustment according to the preset step size. Collect frequency noise spectrum data output by the laser noise analyzer, and calculate the intrinsic linewidth and integral linewidth of the laser at the current injection current based on the frequency noise spectrum data. The historical injection current is updated to the current injection current, and the injection current supplied to the laser by the programmable current source is readjusted according to the preset step size until the injection current reaches the current threshold. Then the intrinsic linewidth and integral linewidth at each injection current are obtained. By utilizing the integral linewidth at each injection current and based on an automatic inflection point identification algorithm, the frequency noise spectrum evolution characteristics of the laser under different injection currents are analyzed. Based on the frequency noise spectrum evolution characteristics, the minimum integral linewidth is determined, wherein the minimum integral linewidth is the integral linewidth of the laser at the optimal operating current. Linewidth test results are generated using the minimum integral linewidth and the intrinsic linewidth at each injected current.

[0007] Based on the above disclosure, this invention adjusts the injection current supplied to the laser by a programmable current source according to a preset step size, based on the injection current of the previous linewidth measurement. After the injection current stabilizes, the output laser light of the laser is connected to a laser noise analyzer. Then, frequency noise spectrum data output by the laser noise analyzer is collected to calculate the intrinsic linewidth and integral linewidth of the laser at the current injection current. Then, based on the current injection current, the laser injection current is adjusted again according to a preset step size until the injection current reaches a current threshold, thus obtaining the intrinsic linewidth and integral linewidth at each injection current. Next, this invention uses the integral linewidth at each injection current and an automatic inflection point recognition algorithm to analyze the frequency noise spectrum evolution characteristics of the laser under different injection currents, thereby determining the integral linewidth (i.e., the minimum integral linewidth) of the laser at the optimal operating current based on the frequency noise spectrum evolution characteristics. Finally, using the minimum integral linewidth and the intrinsic linewidth at each injection current, linewidth test results can be generated.

[0008] Through the above design, this invention acquires frequency noise spectrum data of the laser at different injection currents using a current scanning method with a preset step size. Based on this data, the linewidth of the laser at different injection currents is calculated. Finally, based on the integrated linewidth at different injection currents and using an automatic inflection point identification algorithm, the evolution characteristics of the laser's frequency noise spectrum under different injection currents are analyzed, thereby determining the integrated linewidth of the laser at the optimal operating current. Therefore, this invention provides a new linewidth measurement technology. Compared to traditional delay heterodyne methods and improved zero-beat schemes, it eliminates the need for long / short laser delays, thus avoiding the environmental noise introduced by long fiber delays and the problem of weak signals being submerged by system noise due to short fiber delays, thereby improving measurement accuracy. Simultaneously, this invention enables automatic current scanning over a wide range, significantly improving measurement efficiency compared to traditional static point measurement. Furthermore, measurement is only initiated after each current point has stabilized, effectively avoiding transient response interference, further improving the sensitivity and accuracy of automatic linewidth testing for narrow-linewidth lasers.

[0009] In one possible design, based on the frequency noise spectrum data, the intrinsic linewidth and integral linewidth of the laser at the current injection current are calculated, including: The frequency noise spectrum data is preprocessed to obtain a preprocessed frequency noise spectrum; Background noise is acquired, wherein the background noise is measured after the laser is turned off; Based on the preprocessed frequency noise spectrum and the background noise, the actual frequency noise spectrum is generated; Frequency noise data above a preset frequency band is extracted from the actual frequency noise spectrum, and the intrinsic linewidth of the laser at the current injection current is calculated based on the extracted frequency noise data. The actual frequency noise spectrum is subjected to frequency numerical integration to obtain the integral linewidth of the laser at the current injection current.

[0010] In one possible design, the integral linewidth at each injection current is utilized, and based on an automatic inflection point identification algorithm, the frequency noise spectrum evolution characteristics of the laser under different injection currents are analyzed. Based on these frequency noise spectrum evolution characteristics, the minimum integral linewidth is determined, including: Based on the integral linewidth at each injected current under the preset step size, a current linewidth curve is constructed. Based on the current linewidth curve, a local fine scan of the laser injection current is performed to obtain the candidate optimal operating current of the laser after the local fine scan. Adjust the candidate optimal operating current, and after adjustment, acquire the new frequency noise spectrum data output by the laser noise analyzer; The frequency noise spectrum evolution characteristics of the new frequency noise spectrum data are analyzed to determine the optimal operating current based on the frequency noise spectrum evolution characteristics, and the integration linewidth corresponding to the optimal operating current is taken as the minimum integration linewidth.

[0011] In one possible design, a local fine scan of the laser injection current is performed based on the current linewidth profile to obtain candidate optimal operating currents for the laser after the local fine scan, including: On the current linewidth curve, search for the three consecutive injection current points with the lowest linewidth values; Based on the three injection current points found, a quadratic curve is fitted, and the minimum point on the quadratic curve is determined. By reducing the step accuracy of the preset step size, a reduced preset step size is obtained; Determine whether the preset step size after shrinking has reached the minimum step size; If not, then take the current value corresponding to the minimum point as the center, and control the programmable current source to provide injection current to the laser according to the reduced preset step size, so as to obtain the integral line width at each injection current under the reduced preset step size. A new current linewidth curve is constructed based on the integral linewidth at each injected current under the reduced preset step size; The current linewidth curve is updated to the new current linewidth curve, and the three consecutive injection current points with the lowest linewidth values ​​are searched again until the preset step size is reduced to the minimum step size. The current value corresponding to the minimum point is taken as the candidate optimal operating current of the laser.

[0012] In a possible design, the frequency noise spectrum evolution characteristics of the new frequency noise spectrum data are analyzed to determine the optimal operating current based on these characteristics, including: Extract the low-frequency noise component from the new frequency noise spectrum data; The slope change of the low-frequency noise component is monitored to see if it meets the preset change conditions, wherein the slope change of the low-frequency noise component is used as the frequency noise spectrum evolution feature. If not, the candidate optimal operating current is readjusted until the slope change of the low-frequency noise component meets the preset change conditions, and the adjusted candidate optimal operating current is taken as the optimal operating current.

[0013] In one possible design, the laser is temperature regulated by a dual closed-loop controller during operation. The dual closed-loop controller includes a fast temperature control loop, which collects the real-time temperature of the laser and, based on the temperature error between the real-time temperature and a preset temperature, uses a PID algorithm to adjust the laser temperature to the preset temperature. The method further includes, after calculating the intrinsic linewidth and integral linewidth of the laser at the current injection current: Determine if the laser requires temperature compensation; If so, the laser is temperature compensated using the dual closed-loop controller to adjust the laser temperature to a preset temperature, and after adjusting to the preset temperature, the historical injection current is updated to the current injection current.

[0014] In one possible design, determining whether the laser needs temperature compensation includes: based on the temperature adaptive monitoring and adjustment loop in the dual closed-loop controller, determining whether the absolute value of the temperature error is greater than the error threshold, wherein if the absolute value of the temperature error is greater than the error threshold, the laser is temperature compensated using the dual closed-loop controller. Accordingly, temperature compensation for the laser using the dual closed-loop controller includes: The scanning process is paused, which includes adjusting the injection current of the laser and acquiring the frequency noise spectrum data output by the laser noise analyzer. The laser's real-time temperature is reacquired through a rapid temperature control loop. Based on the temperature error between the real-time temperature and the preset temperature, and using a PID algorithm, the laser's temperature is adjusted until the absolute value of the temperature error is less than or equal to the minimum error threshold, and the duration for which the absolute value of the temperature error is less than or equal to the minimum error threshold is greater than the preset duration. Then, the scanning process is resumed.

[0015] Secondly, an automatic testing system for the current linewidth of narrow-linewidth lasers is provided, including: The current injection unit is used to adjust the injection current provided to the laser by the programmable current source according to a preset step size based on the historical injection current, and to connect the output laser of the laser to the laser noise analyzer after the injection current stabilizes. The historical injection current is the injection current provided to the laser by the programmable current source after the last adjustment according to the preset step size. The data processing unit is used to acquire the frequency noise spectrum data output by the laser noise analyzer, and calculate the intrinsic linewidth and integral linewidth of the laser at the current injection current based on the frequency noise spectrum data. The data processing unit is also used to update the historical injection current to the current injection current, and readjust the injection current supplied to the laser by the programmable current source according to the preset step size until the injection current reaches the current threshold, and obtain the intrinsic linewidth and integral linewidth at each injection current. The linewidth testing unit is used to analyze the frequency noise spectrum evolution characteristics of the laser under different injection currents by utilizing the integrated linewidth at each injection current and based on an automatic inflection point identification algorithm, so as to determine the minimum integrated linewidth based on the frequency noise spectrum evolution characteristics, wherein the minimum integrated linewidth is the integrated linewidth of the laser under the optimal operating current. The linewidth testing unit is also used to generate linewidth test results using the minimum integrated linewidth and the intrinsic linewidth at each injected current.

[0016] Thirdly, an automatic testing device for the current linewidth of a narrow-linewidth laser is provided. Taking the device as an electronic device as an example, it includes a memory, a processor, and a transceiver that are connected in sequence. The memory is used to store a computer program, the transceiver is used to send and receive messages, and the processor is used to read the computer program and execute the automatic testing method for the current linewidth of a narrow-linewidth laser as described in the first aspect or any possible design of the first aspect.

[0017] Fourthly, a storage medium is provided, on which instructions are stored, which, when executed on a computer, perform the automatic testing method for narrow linewidth laser current as described in the first aspect or any possible design of the first aspect.

[0018] Fifthly, a computer program product containing instructions is provided, which, when executed on a computer, causes the computer to perform the automatic test method for narrow linewidth laser current as described in the first aspect or any possible design of the first aspect.

[0019] Beneficial effects: (1) This invention collects frequency noise spectrum data of the laser at different injection currents by using a current scanning method with a preset step size, and calculates the linewidth of the laser at different injection currents based on the frequency noise spectrum data at different injection currents; finally, based on the integrated linewidth at different injection currents, and using an automatic inflection point identification algorithm, the evolution characteristics of the frequency noise spectrum of the laser under different injection currents are analyzed, and the integrated linewidth of the laser at the optimal operating current is determined accordingly; thus, this invention provides a new linewidth measurement technology, which, compared with the traditional delay heterodyne method and the improved zero-beat scheme, does not require long / short laser delay, thus avoiding the problem of environmental noise introduced by long fiber delay and weak signals caused by short fiber delay being submerged by system noise, thereby improving the measurement accuracy.

[0020] (2) The present invention can realize automatic current scanning over a wide range, which greatly improves the measurement efficiency compared with the traditional static point measurement mode. Moreover, the measurement is started only after each current point stabilizes. Based on this, transient response interference can be effectively avoided, thereby further improving the sensitivity and accuracy of automatic linewidth testing of narrow linewidth lasers. Attached Figure Description

[0021] Figure 1 A flowchart illustrating the steps of the automatic testing method for the current linewidth of a narrow-linewidth laser provided in an embodiment of the present invention; Figure 2 A schematic diagram of the structure of the automatic testing system for narrow linewidth laser current linewidth provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be briefly introduced below in conjunction with the accompanying drawings and descriptions of the embodiments or the prior art. Obviously, the following description of the structure of the accompanying drawings is 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. It should be noted that the description of these embodiments is for the purpose of helping to understand the present invention, but does not constitute a limitation of the present invention.

[0023] It should be understood that although the terms first, second, etc., may be used herein to describe various units, these units should not be limited by these terms. These terms are only used to distinguish one unit from another. For example, a first unit may be referred to as a second unit, and similarly, a second unit may be referred to as a first unit, without departing from the scope of the exemplary embodiments of the invention.

[0024] It should be understood that the term "and / or" that may appear in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist simultaneously. The term " / and" that may appear in this document describes another relationship between related objects, indicating that two relationships can exist. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " that may appear in this document generally indicates that the related objects before and after it are in an "or" relationship.

[0025] Example: Before describing the automatic testing method for narrow-linewidth laser current linewidth provided in this embodiment, an automatic testing system for narrow-linewidth laser current linewidth is first provided. This system may include, but is not limited to: a high-precision drive module (programmable current source, range 0-500mA, step size 0.1mA); a coherent detection unit (laser noise analyzer, such as a GP-LWM100 analyzer, center wavelength 1530nm-1625nm); and a dynamic temperature control subsystem, which includes a dual closed-loop controller. The inner loop is a fast temperature control loop, and the outer loop is a temperature adaptive monitoring and adjustment loop. The inner loop uses a semiconductor thermoelectric cooler to regulate the laser temperature in real time (accuracy ±0.1℃). When the temperature drift >0.1℃, the outer loop, based on NTC thermistor temperature monitoring, will pause scanning and... The system employs several mechanisms: Initiation of compensation; intelligent optical path adapter (automatic attenuator for dynamically adjusting input power from -8dBm to 0dBm); data processing engine: real-time execution of noise state estimation algorithms, outputting intrinsic and integral linewidths; The system's workflow is as follows: The center wavelength of the narrow-linewidth laser is controlled by a high-precision current source (i.e., the injection current of the laser is adjusted by a programmable current source). The laser signal emitted by the narrow-linewidth laser then enters the GP-LWM100 analyzer for parameter performance evaluation. Internal and external dual closed-loop controllers address the thermal effects caused by current tuning. Finally, the linewidth is calculated based on the data processing engine, and the frequency noise spectrum evolution characteristics under different injection currents are analyzed to accurately locate the linewidth minimum point (i.e., the optimal operating current of the laser).

[0026] Thus, this embodiment combines the sub-Hertz detection capability of the GP-LWM100 with a high-resolution programmable current source (0.1 step). The system deeply integrates with an industrial computer for collaborative control. On one hand, it collects frequency noise spectrum data of the laser at different injection currents using a current scanning method with preset step sizes. Based on this data, it calculates the linewidth of the laser at different injection currents. Finally, based on the integrated linewidth at different injection currents and using an automatic inflection point identification algorithm, it analyzes the evolution characteristics of the laser's frequency noise spectrum under different injection currents, thereby determining the integrated linewidth of the laser at the optimal operating current. Therefore, compared to traditional delay heterodyne methods and improved zero-beat schemes, this system eliminates the need for long / short laser delays, thus avoiding environmental noise introduced by long fiber delays and the problem of weak signals being submerged by system noise due to short fiber delays, thereby improving measurement accuracy. On the other hand, this system can achieve automatic current scanning over a wide range, greatly improving measurement efficiency compared to traditional static point measurement. Measurement is only initiated after each current point has stabilized, effectively avoiding transient response interference, further improving the sensitivity and accuracy of automatic linewidth testing for narrow-linewidth lasers.

[0027] Among them, see Figure 1 As shown, the automatic testing method for narrow linewidth laser current linewidth provided in this embodiment can be run on the data processing engine side of the automatic testing system for narrow linewidth laser current linewidth. Optionally, the data processing engine can be, but is not limited to, a computer or a server. It is understood that the aforementioned execution subject does not constitute a limitation on the embodiments of this application. Accordingly, the operation steps of this method can be, but are not limited to, the steps S1 to S5 below.

[0028] S1. Based on the historical injection current, the injection current provided to the laser by the programmable current source is adjusted according to a preset step size. After the injection current stabilizes, the output laser of the laser is connected to a laser noise analyzer. The historical injection current is the injection current provided to the laser by the programmable current source after the last adjustment according to the preset step size. In this embodiment, assuming the initial current is 1.2mA and the preset step size is 0.1mA, then after the first adjustment according to the preset step size, the injection current provided to the laser by the programmable current source is 1.3mA. After completing the linewidth measurement at 1.3mA, the next measurement will be at 1.4mA. Thus, the injection current used for each linewidth measurement is based on the previous injection current plus the preset step size. Based on this, automatic current scanning over a large range can be achieved. Of course, the current can be gradually increased or decreased according to the aforementioned preset step size, which is not specifically limited in this embodiment.

[0029] For example, after adjusting the injection current of the programmable current source, a fixed time is waited for the injection current to be determined to be stable. Also, for example, the laser (i.e., a narrow linewidth laser) is connected to the laser noise analyzer via an automatic attenuator. This ensures that the optical power entering the laser noise analyzer (i.e., the GP-LWM100 analyzer) remains between -8dBm and 0dBm. Furthermore, after determining that the injection current is stable, the connection between the laser and the automatic attenuator can be established, thus enabling the input of the output laser.

[0030] After adjusting the injection current of the laser, a laser noise analyzer can be used to collect the frequency noise spectrum data at the current injection current, so as to calculate the linewidth at the current injection current based on the collected frequency noise spectrum data; the data acquisition process is as shown in step S2 below.

[0031] S2. Collect the frequency noise spectrum data output by the laser noise analyzer, and calculate the intrinsic linewidth and integral linewidth of the laser at the current injection current based on the frequency noise spectrum data.

[0032] In this embodiment, the laser is operated using a dual closed-loop controller to address temperature instability caused by the thermal effect of the control. The inner loop uses a semiconductor thermoelectric cooler to control the laser temperature in real time (accuracy ±0.1℃). When the temperature drift is >0.1℃, the outer loop monitors the temperature based on an NTC thermistor. When the absolute value of the temperature error is greater than the error threshold, the scanning is paused and compensation is initiated.

[0033] Thus, the laser employs a dual-loop controller for temperature regulation. This dual-loop controller includes a fast temperature control loop and a temperature adaptive monitoring and adjustment loop. The fast temperature control loop collects the laser's real-time temperature and, based on the temperature error between the real-time temperature and a preset temperature, uses a PID algorithm to adjust the laser temperature to the preset temperature. Specifically, the fast temperature control loop includes: a sensor; an NTC (negative temperature coefficient) thermistor integrated inside the laser, which monitors the laser chip temperature in real time; and an actuator (thermoelectric thermoelectric cooler (TEC)). The fast temperature control loop uses a PID (proportional-integral-derivative) control algorithm to regulate the laser temperature. It compares the set target temperature with the temperature fed back by the NTC in real time to obtain the temperature error. The PID controller calculates the current signal driving the TEC based on the proportional, integral, and derivative terms of the error, thereby quickly offsetting temperature fluctuations and stabilizing the laser temperature near the set value (with an accuracy of ±0.1℃).

[0034] The temperature adaptive monitoring and adjustment loop monitors the temperature error data of the inner loop in real time. When the absolute value of the temperature error of the inner loop is detected to be >0.1℃, it indicates that the thermal effect caused by the change in current has exceeded the rapid compensation capability of the inner loop. At this time, the outer loop algorithm is immediately connected to perform temperature compensation for the laser. The temperature compensation process is described in detail below.

[0035] Based on this, after temperature control is completed, noise spectrum analysis can be performed. The core function of the laser noise analyzer is to directly measure and output the frequency noise spectrum of the laser. The horizontal axis of the spectrum is the Fourier frequency, and the vertical axis is the power spectral density. Therefore, the linewidth can be calculated based on the frequency noise spectrum data, as shown in steps S21 to S25 below.

[0036] S21. The frequency noise spectrum data is preprocessed to obtain a preprocessed frequency noise spectrum. In this embodiment, the preprocessing of the frequency noise spectrum data may include, but is not limited to, smoothing the frequency noise spectrum data to suppress random noise interference. Thus, after the data preprocessing is completed, the background noise can be obtained, as shown in step S22 below.

[0037] S22. Obtain background noise, wherein the background noise is measured after the laser is turned off; in specific applications, the background noise is the system noise measured after the laser is turned off, which can be pre-measured and pre-stored in the data processing engine; based on this, after obtaining the background noise, the system noise floor can be removed, the process of which is shown in step S23 below.

[0038] S23. Based on the preprocessed frequency noise spectrum and the background noise, generate the actual frequency noise spectrum; in this embodiment, the actual frequency noise spectrum can be obtained by subtracting the background noise from the preprocessed frequency noise spectrum; then, the linewidth can be calculated, as shown in steps S24 and S25 below.

[0039] S24. Extract frequency noise data above a preset frequency band from the actual frequency noise spectrum, and calculate the intrinsic linewidth of the laser at the current injection current based on the extracted frequency noise data. In specific implementation, the intrinsic linewidth corresponds to the white noise plateau in the frequency noise spectrum, i.e., the noise floor that is independent of frequency. Therefore, for example, but not limited to, extracting frequency noise data above 1MHz from the actual frequency noise spectrum; then, calculate the mean of the power spectral density of the frequency noise data above 1MHz; finally, the intrinsic linewidth at the current injection current can be calculated based on the mean of the power spectral density.

[0040] Optionally, for example, but not limited to, the following formula can be used to calculate the intrinsic linewidth.

[0041] ; In the formula, The intrinsic linewidth at the current injection current. This is the mean of the power spectral density.

[0042] After calculating the intrinsic linewidth, the integral linewidth can be calculated, as shown in step S25 below.

[0043] S25. Perform frequency numerical integration on the actual frequency noise spectrum to obtain the integral linewidth of the laser at the current injection current after the frequency numerical integration. In specific implementation, the integral linewidth includes the overall linewidth of all frequency noise contributions, especially low-frequency noise, and can better reflect the actual coherence performance of the laser. Therefore, for example, but not limited to, numerical integration can be performed on the entire frequency noise spectrum from low frequency to high frequency to obtain the integral linewidth.

[0044] For example, the integral linewidth can be calculated using, but is not limited to, the following formula.

[0045] ; In the formula, Indicates the width of the integral line. Represents the actual frequency noise spectrum. The maximum Fourier frequency, This involves integrating the Fourier frequencies.

[0046] Thus, through the aforementioned steps S21 to S25, the linewidth at the current injection current can be calculated based on the frequency noise spectrum data at the current injection current. Then, it can be determined whether temperature compensation is needed, the process of which is as follows: S26. After calculating the intrinsic linewidth and integral linewidth of the laser at the current injection current, determine whether the laser needs temperature compensation. In this embodiment, the temperature adaptive monitoring and adjustment loop in the dual closed-loop controller is used to determine whether the absolute value of the temperature error is greater than the error threshold (i.e., 0.1℃). If the absolute value of the temperature error is greater than the error threshold, the dual closed-loop controller is used to perform temperature compensation on the laser, i.e., step S27 is executed below; otherwise, step S3 is executed directly below.

[0047] S27. If so, the laser is temperature compensated using the dual closed-loop controller to adjust the laser temperature to a preset temperature, and after adjusting to the preset temperature, the historical injection current is updated to the current injection current.

[0048] In this embodiment, the temperature compensation process is as follows: First, the scanning process is paused (the scanning process includes adjusting the injection current of the laser and acquiring the frequency noise spectrum data output by the laser noise analyzer); then, the real-time temperature of the laser is reacquired through a fast temperature control loop, and the laser temperature is adjusted based on the temperature error between the real-time temperature and the preset temperature, and using a PID algorithm, until the absolute value of the temperature error is less than or equal to the minimum error threshold, and the duration for which the absolute value of the temperature error is less than or equal to the minimum error threshold is greater than the preset duration, at which point the scanning process is resumed.

[0049] Furthermore, the following section provides a more detailed explanation of temperature compensation: When the absolute value of the temperature error in the inner loop is detected to be >0.1℃, it indicates that the thermal effect caused by the current change has exceeded the rapid compensation capability of the inner loop. The outer loop algorithm immediately intervenes, and the process is as follows: a. Pause scanning: immediately pause current scanning and linewidth measurement, and fix the current; b. Start compensation: immediately interrupt the ongoing automatic scanning process, including pausing current stepping and data acquisition of GP-LWM100, and stabilize the entire system at the current current state; then, temperature adjustment is performed, that is, the system completely hands over control to the temperature control subsystem. Under the drive of the inner loop PID controller, the TEC pulls the laser temperature back to the set value as quickly as possible; at this time, temperature control has the highest priority, and the system will wait and no longer perform any operations that may introduce thermal disturbances; at the same time, after the temperature recovers, stability verification and recovery are also set, that is: the system continuously monitors the temperature until the absolute value of the temperature error in the inner loop is ≤0.05℃ and maintains it for a period of time (such as 1 second). At this time, it can be determined that the temperature has stabilized again.

[0050] Once the temperature stabilizes, the system will re-measure the linewidth at the current point to ensure data validity. Then, the system automatically resumes the scanning task from the previously paused current point. Furthermore, if temperature drift occurs frequently, the control parameters of the inner-loop PID controller can be adaptively adjusted, such as increasing the integral gain and decreasing the current scan step speed. Thus, once the laser temperature drift gradually stabilizes, the system can adjust and compensate according to the set parameters to better adapt to the specific thermal characteristics of the laser.

[0051] Thus, after temperature compensation is completed, the next current point can be scanned, and the above process is repeated until the current threshold is reached; wherein, the continuous current scanning process is as shown in step S3 below.

[0052] S3. Update the historical injection current to the current injection current, and readjust the injection current supplied to the laser by the programmable current source according to the preset step size until the injection current reaches the current threshold, and obtain the intrinsic linewidth and integral linewidth at each injection current. In specific implementation, after completing the current scan according to the preset step size, the intrinsic linewidth and integral linewidth at each injection current point can be obtained. Then, the integral linewidth at each current point can be used to perform frequency noise spectrum evolution characteristic analysis, and the minimum integral linewidth can be determined based on the frequency noise spectrum evolution characteristics obtained from the analysis.

[0053] The frequency noise spectrum evolution characteristic analysis is shown in step S4 below.

[0054] S4. Utilizing the integral linewidth at each injection current and based on an automatic inflection point identification algorithm, analyze the frequency noise spectrum evolution characteristics of the laser under different injection currents to determine the minimum integral linewidth based on the frequency noise spectrum evolution characteristics. The minimum integral linewidth is the integral linewidth of the laser at its optimal operating current. In practical applications, this embodiment utilizes the frequency noise sensitivity of a laser noise analyzer to develop an automatic inflection point identification algorithm. This algorithm is used to accurately locate the minimum linewidth point (i.e., the optimal operating current of the laser) by analyzing the frequency noise spectrum evolution characteristics under different injection currents. The frequency noise spectrum evolution characteristic analysis process based on automatic inflection point identification is shown in steps S41 to S44 below.

[0055] S41. Based on the integral linewidth at each injected current under the preset step size, a current linewidth curve is constructed. In this embodiment, the injected current is used as the abscissa and the integral linewidth corresponding to each injected current is used as the ordinate to construct the current linewidth curve. Then, a local fine scan can be performed based on the current linewidth curve, as shown in step S42 below.

[0056] S42. Based on the current linewidth curve, perform a local fine scan of the laser injection current to obtain the candidate optimal operating current of the laser after the local fine scan; in specific implementation, for example, but not limited to, the following steps S42a to S42g can be used to perform a local fine scan of the injection current to obtain the candidate optimal operating current of the laser.

[0057] S42a. On the current linewidth curve, search for the three consecutive injection current points with the lowest linewidth values.

[0058] After searching for the three consecutive injection current points with the lowest integral linewidth values ​​on the current linewidth curve, curve fitting can be performed, as shown in step S42b below.

[0059] S42b. Based on the three injection current points found, a quadratic curve is fitted and the minimum point on the quadratic curve is determined. In specific implementation, the quadratic curve is fitted with these three points to calculate the current value corresponding to the minimum point of the curve. Then, the local fine scan is performed using the current value corresponding to the minimum point. The process is as shown in the following steps S42c to S42g.

[0060] S42c. Reduce the step precision of the preset step size to obtain a reduced preset step size; in this embodiment, it is equivalent to adjusting the current step precision to perform fine current scanning with a smaller step size; before scanning, it is necessary to determine whether the reduced preset step size has reached the minimum step size, that is, whether the minimum step precision has been reached, and the determination process is shown in step S42d below.

[0061] S42d. Determine whether the reduced preset step size has reached the minimum step size; in specific implementation, the minimum step size can be set according to actual use, and is not specifically limited here; at the same time, when the reduced preset step size has not reached the minimum step size, it is necessary to use the current value corresponding to the aforementioned minimum point as the center and perform current scanning according to the reduced preset step size, as shown in step S42e below.

[0062] S42e. If not, then using the current value corresponding to the minimum point as the center, and controlling the programmable current source to provide injection current to the laser according to the reduced preset step size, so as to obtain the integral linewidth at each injection current under the reduced preset step size; in this embodiment, the process of adjusting the injection current using the current value corresponding to the minimum point as the center and according to the reduced preset step size can be referred to the aforementioned step S1; at the same time, after adjustment, the frequency noise spectrum data output by the laser noise analyzer can be collected, and based on this, the intrinsic linewidth and integral linewidth can be calculated; then, the current value is increased or decreased according to the reduced preset step size until the current threshold is reached, then the integral linewidth at each injection current under the reduced preset step size can be obtained; thus, the current linewidth curve can be reconstructed based on the integral linewidth at each injection current under the reduced preset step size, and the aforementioned process is repeated until the reduced preset step size reaches the minimum step size, then the current value closest to the optimal operating current can be obtained.

[0063] The process of continuously performing local fine scanning is shown in steps S42f and S42g below.

[0064] S42f. Based on the integral linewidth at each injected current under the reduced preset step size, a new current linewidth curve is constructed.

[0065] S42g. Update the current linewidth curve to the new current linewidth curve, and re-search for the three consecutive injection current points with the lowest linewidth values ​​until the reduced preset step size reaches the minimum step size. Then, take the current value corresponding to the minimum point as the candidate optimal operating current of the laser.

[0066] After completing the local fine scanning of the injected current through the aforementioned steps S42a to S42g, this embodiment will also analyze the shape evolution of the frequency noise spectrum to help verify the inflection point (i.e. the optimal operating current point), as shown in steps S43 and S44 below.

[0067] S43. Adjust the candidate optimal operating current, and after adjustment, collect the new frequency noise spectrum data output by the laser noise analyzer; in this embodiment, it is equivalent to adjusting the current value (such as increasing or decreasing the minimum step size) with the candidate optimal operating current as the center, so that a new frequency noise spectrum data will be obtained after each adjustment; then, the inflection point can be verified by analyzing the new frequency noise spectrum data, the process of which is shown in step S44 below.

[0068] S44. Analyze the frequency noise spectrum evolution characteristics of the new frequency noise spectrum data, determine the optimal operating current based on the frequency noise spectrum evolution characteristics, and take the integration linewidth corresponding to the optimal operating current as the minimum integration linewidth; in specific implementation, for example, but not limited to, the following steps S44a to S44c can be used to perform the shape evolution analysis of the frequency noise spectrum.

[0069] S44a. Extract the low-frequency noise component from the new frequency noise spectrum data.

[0070] S44b. Monitor whether the slope change of the low-frequency noise component meets the preset change conditions, wherein the slope change of the low-frequency noise component serves as the frequency noise spectrum evolution characteristic. In specific implementation, when the current approaches the optimal point, the low-frequency noise component decreases significantly, and the white noise plateau tends to flatten. Therefore, the inflection point can be verified by monitoring the slope change of the low-frequency noise. For example, the preset change condition is that the change amplitude of the slope is greater than a preset threshold. If the aforementioned condition is not met, the candidate optimal operating current needs to be adjusted again based on the previous adjustment, and the aforementioned process is repeated until the slope change meets the preset change conditions, at which point the optimal operating current can be obtained. The continuous adjustment process is shown in step S44c below.

[0071] S44c. If not, then readjust the candidate optimal operating current until the slope change of the low-frequency noise component meets the preset change conditions, and then take the adjusted candidate optimal operating current as the optimal operating current.

[0072] Thus, through the aforementioned steps S41 to S44 and their corresponding sub-steps, the automatic inflection point recognition algorithm can be summarized as follows: The integral linewidth value corresponding to each current point is plotted as a current-linewidth curve. Then, a numerical optimization algorithm is used to search for the minimum point on the current-linewidth curve. The specific steps are as follows: within the initial scan range, the three consecutive current points with the lowest linewidth values ​​are identified; a quadratic curve is fitted to these three points, and the current value corresponding to the minimum point of the curve is calculated; then, with this current value as the center, a local fine scan is performed by continuously reducing the step size. At this time, the linewidth continuously decreases with the local fine scan of the current. The above fitting process is repeated until the current step accuracy reaches the minimum step accuracy. At this time, the linewidth is close to the minimum linewidth. At the same time, the algorithm also analyzes the shape evolution of the frequency noise spectrum: when the current is close to the optimal point, the low-frequency noise component is significantly reduced, and the white noise plateau tends to flatten. Therefore, the algorithm uses the change of the low-frequency noise slope to help verify the inflection point. That is, when the current step accuracy reaches the minimum step accuracy, the current is adjusted to make the low-frequency noise component significantly reduced (i.e., the slope change meets the preset change conditions). The current value at this time is marked as the inflection point, which is the optimal operating current value.

[0073] Finally, the algorithm automatically outputs the optimal operating current value and the corresponding minimum integral linewidth, and marks it as the "inflection point". In this way, this embodiment can accurately locate the minimum linewidth point (i.e., the optimal operating current) by analyzing the frequency noise spectrum evolution characteristics under different currents. Experiments show that the algorithm has an optimal current identification accuracy of ±0.1 mA for a 1550 nm DFB laser, which is significantly better than the traditional trial and error method.

[0074] After obtaining the minimum integrated linewidth, the linewidth test results can be generated by combining the intrinsic linewidths at each of the aforementioned injection currents, as shown in step S5 below.

[0075] S5. Generate linewidth test results using the minimum integral linewidth and the intrinsic linewidth at each injected current.

[0076] Therefore, through the automatic testing method for the current linewidth of narrow-linewidth lasers described in detail in steps S1 to S5 above, this invention provides a new linewidth measurement technology. Compared with the traditional delay heterodyne method and the improved zero-beat scheme, it eliminates the need for long / short laser delays. This avoids the environmental noise introduced by long fiber delays and the problem of weak signals being submerged by system noise due to short fiber delays, thereby improving measurement accuracy. At the same time, this invention can achieve automatic current scanning over a wide range, which greatly improves measurement efficiency compared with the traditional static point measurement mode. Moreover, the measurement is only started after each current point has stabilized. Based on this, transient response interference can be effectively avoided, further improving the sensitivity and accuracy of automatic testing of the linewidth of narrow-linewidth lasers. Therefore, this invention is very suitable for large-scale application and promotion.

[0077] like Figure 2As shown, the second aspect of this embodiment provides a hardware system for implementing the automatic testing method for narrow linewidth laser current linewidth described in the first aspect of the embodiment, wherein, taking the system as a data processing engine as an example, it includes: The current injection unit is used to adjust the injection current provided to the laser by the programmable current source according to a preset step size based on the historical injection current, and to connect the output laser of the laser to the laser noise analyzer after the injection current stabilizes. The historical injection current is the injection current provided to the laser by the programmable current source after the last adjustment according to the preset step size.

[0078] The data processing unit is used to acquire the frequency noise spectrum data output by the laser noise analyzer, and calculate the intrinsic linewidth and integral linewidth of the laser at the current injection current based on the frequency noise spectrum data.

[0079] The data processing unit is also used to update the historical injection current to the current injection current, and readjust the injection current supplied to the laser by the programmable current source according to the preset step size until the injection current reaches the current threshold, and obtain the intrinsic linewidth and integral linewidth at each injection current.

[0080] The linewidth testing unit is used to analyze the frequency noise spectrum evolution characteristics of the laser under different injection currents by utilizing the integrated linewidth at each injection current and based on an automatic inflection point identification algorithm, so as to determine the minimum integrated linewidth based on the frequency noise spectrum evolution characteristics, wherein the minimum integrated linewidth is the integrated linewidth of the laser under the optimal operating current.

[0081] The linewidth testing unit is also used to generate linewidth test results using the minimum integrated linewidth and the intrinsic linewidth at each injected current.

[0082] The working process, working details and technical effects of the system provided in this embodiment can be found in the first aspect of the embodiment, and will not be repeated here.

[0083] like Figure 3 As shown, the third aspect of this embodiment provides an automatic testing device for the current linewidth of a narrow-linewidth laser. Taking the device as an electronic device as an example, it includes: a memory, a processor, and a transceiver that are connected in sequence. The memory is used to store a computer program, the transceiver is used to send and receive messages, and the processor is used to read the computer program and execute the automatic testing method for the current linewidth of a narrow-linewidth laser as described in the first aspect of the embodiment.

[0084] For specific examples, the memory may include, but is not limited to, random access memory (RAM), read-only memory (ROM), flash memory, first-in-first-out (FIFO) memory, and / or first-in-last-out (FILO) memory, etc.; specifically, the processor may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor may be implemented using at least one hardware form of DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), PLA (Programmable Logic Array). The processor may also include a main processor and a coprocessor. The main processor, also known as the CPU (Central Processing Unit), is used to process data in the wake-up state; the coprocessor is a low-power processor used to process data in the standby state.

[0085] In some embodiments, the processor may integrate a GPU (Graphics Processing Unit), which is responsible for rendering and drawing the content to be displayed on the screen. For example, the processor may not be limited to microprocessors of the STM32F105 series, reduced instruction set computer (RISC) microprocessors, x86 architecture processors, or processors with integrated neural network processing units (NPUs). The transceiver may be, but is not limited to, a Wi-Fi transceiver, a Bluetooth transceiver, a General Packet Radio Service (GPRS) transceiver, a ZigBee (a low-power LAN protocol based on the IEEE 802.15.4 standard) transceiver, a 3G transceiver, a 4G transceiver, and / or a 5G transceiver. Furthermore, the device may also include, but is not limited to, a power module, a display screen, and other necessary components.

[0086] The working process, working details and technical effects of the electronic device provided in this embodiment can be found in the first aspect of the embodiment, and will not be repeated here.

[0087] The fourth aspect of this embodiment provides a storage medium that stores instructions containing the automatic testing method for narrow linewidth laser current linewidth as described in the first aspect of the embodiment. That is, the storage medium stores instructions that, when executed on a computer, perform the automatic testing method for narrow linewidth laser current linewidth as described in the first aspect of the embodiment.

[0088] The storage medium refers to a carrier for storing data, which may include, but is not limited to, floppy disks, optical disks, hard disks, flash memory, USB flash drives, and / or memory sticks. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.

[0089] The working process, working details and technical effects of the storage medium provided in this embodiment can be found in the first aspect of the embodiment, and will not be repeated here.

[0090] The fifth aspect of this embodiment provides a computer program product containing instructions that, when executed on a computer, cause the computer to perform the automatic testing method for narrow linewidth laser current linewidth as described in the first aspect of this embodiment, wherein the computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device.

[0091] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An automatic method for testing the current linewidth of a narrow-linewidth laser, characterized in that, include: Based on the historical injection current, the injection current supplied to the laser by the programmable current source is adjusted according to a preset step size. After the injection current stabilizes, the output laser of the laser is connected to the laser noise analyzer. The historical injection current is the injection current supplied to the laser by the programmable current source after the last adjustment according to the preset step size. Collect frequency noise spectrum data output by the laser noise analyzer, and calculate the intrinsic linewidth and integral linewidth of the laser at the current injection current based on the frequency noise spectrum data. The historical injection current is updated to the current injection current, and the injection current supplied to the laser by the programmable current source is readjusted according to the preset step size until the injection current reaches the current threshold. Then the intrinsic linewidth and integral linewidth at each injection current are obtained. By utilizing the integral linewidth at each injection current and based on an automatic inflection point identification algorithm, the frequency noise spectrum evolution characteristics of the laser under different injection currents are analyzed. Based on the frequency noise spectrum evolution characteristics, the minimum integral linewidth is determined, wherein the minimum integral linewidth is the integral linewidth of the laser at the optimal operating current. Linewidth test results are generated using the minimum integral linewidth and the intrinsic linewidth at each injected current.

2. The method according to claim 1, characterized in that, Based on the frequency noise spectrum data, the intrinsic linewidth and integral linewidth of the laser at the current injection current are calculated, including: The frequency noise spectrum data is preprocessed to obtain a preprocessed frequency noise spectrum; Background noise is acquired, wherein the background noise is measured after the laser is turned off; Based on the preprocessed frequency noise spectrum and the background noise, the actual frequency noise spectrum is generated; Frequency noise data above a preset frequency band is extracted from the actual frequency noise spectrum, and the intrinsic linewidth of the laser at the current injection current is calculated based on the extracted frequency noise data. The actual frequency noise spectrum is subjected to frequency numerical integration to obtain the integral linewidth of the laser at the current injection current.

3. The method according to claim 1, characterized in that, By utilizing the integral linewidth at each injection current and based on an automatic inflection point identification algorithm, the frequency noise spectrum evolution characteristics of the laser under different injection currents are analyzed, in order to identify these characteristics. Determine the minimum integration linewidth, including: Based on the integral linewidth at each injected current under the preset step size, a current linewidth curve is constructed. Based on the current linewidth curve, a local fine scan of the laser injection current is performed to obtain the candidate optimal operating current of the laser after the local fine scan. Adjust the candidate optimal operating current, and after adjustment, acquire the new frequency noise spectrum data output by the laser noise analyzer; The frequency noise spectrum evolution characteristics of the new frequency noise spectrum data are analyzed to determine the optimal operating current based on the frequency noise spectrum evolution characteristics, and the integration linewidth corresponding to the optimal operating current is taken as the minimum integration linewidth.

4. The method according to claim 3, characterized in that, Based on the current linewidth curve, a local fine scan of the laser injection current is performed to obtain the candidate optimal operating current of the laser after the local fine scan, including: On the current linewidth curve, search for the three consecutive injection current points with the lowest linewidth values; Based on the three injection current points found, a quadratic curve is fitted, and the minimum point on the quadratic curve is determined. By reducing the step accuracy of the preset step size, a reduced preset step size is obtained; Determine whether the preset step size after shrinking has reached the minimum step size; If not, then take the current value corresponding to the minimum point as the center, and control the programmable current source to provide injection current to the laser according to the reduced preset step size, so as to obtain the integral line width at each injection current under the reduced preset step size. A new current linewidth curve is constructed based on the integral linewidth at each injected current under the reduced preset step size; The current linewidth curve is updated to the new current linewidth curve, and the three consecutive injection current points with the lowest linewidth values ​​are searched again until the preset step size is reduced to the minimum step size. The current value corresponding to the minimum point is taken as the candidate optimal operating current of the laser.

5. The method according to claim 3, characterized in that, Analyze the frequency noise spectrum evolution characteristics of the new frequency noise spectrum data to determine the optimal operating current based on these characteristics, including: Extract the low-frequency noise component from the new frequency noise spectrum data; The slope change of the low-frequency noise component is monitored to see if it meets the preset change conditions, wherein the slope change of the low-frequency noise component is used as the frequency noise spectrum evolution feature. If not, the candidate optimal operating current is readjusted until the slope change of the low-frequency noise component meets the preset change conditions, and the adjusted candidate optimal operating current is taken as the optimal operating current.

6. The method according to claim 1, characterized in that, During operation, the laser is temperature regulated using a dual closed-loop controller. The dual closed-loop controller includes a fast temperature control loop, which collects the real-time temperature of the laser and, based on the temperature error between the real-time temperature and the preset temperature, uses a PID algorithm to adjust the laser temperature to the preset temperature. The method further includes, after calculating the intrinsic linewidth and integral linewidth of the laser at the current injection current: Determine if the laser requires temperature compensation; If so, the laser is temperature compensated using the dual closed-loop controller to adjust the laser temperature to a preset temperature, and after adjusting to the preset temperature, the historical injection current is updated to the current injection current.

7. The method according to claim 6, characterized in that, Determining whether a laser needs temperature compensation includes: based on the temperature adaptive monitoring and adjustment loop in the dual closed-loop controller, determining whether the absolute value of the temperature error is greater than the error threshold; if the absolute value of the temperature error is greater than the error threshold, then the dual closed-loop controller is used to perform temperature compensation on the laser. Accordingly, temperature compensation for the laser using the dual closed-loop controller includes: The scanning process is paused, which includes adjusting the injection current of the laser and acquiring the frequency noise spectrum data output by the laser noise analyzer. The laser's real-time temperature is reacquired through a rapid temperature control loop. Based on the temperature error between the real-time temperature and the preset temperature, and using a PID algorithm, the laser's temperature is adjusted until the absolute value of the temperature error is less than or equal to the minimum error threshold, and the duration for which the absolute value of the temperature error is less than or equal to the minimum error threshold is greater than the preset duration. Then, the scanning process is resumed.

8. An automatic testing system for the current linewidth of a narrow-linewidth laser, characterized in that, include: The current injection unit is used to adjust the injection current provided to the laser by the programmable current source according to a preset step size based on the historical injection current, and to connect the output laser of the laser to the laser noise analyzer after the injection current stabilizes. The historical injection current is the injection current provided to the laser by the programmable current source after the last adjustment according to the preset step size. The data processing unit is used to acquire the frequency noise spectrum data output by the laser noise analyzer, and calculate the intrinsic linewidth and integral linewidth of the laser at the current injection current based on the frequency noise spectrum data. The data processing unit is also used to update the historical injection current to the current injection current, and readjust the injection current supplied to the laser by the programmable current source according to the preset step size until the injection current reaches the current threshold, and obtain the intrinsic linewidth and integral linewidth at each injection current. The linewidth testing unit is used to analyze the frequency noise spectrum evolution characteristics of the laser under different injection currents by utilizing the integrated linewidth at each injection current and based on an automatic inflection point identification algorithm, so as to determine the minimum integrated linewidth based on the frequency noise spectrum evolution characteristics, wherein the minimum integrated linewidth is the integrated linewidth of the laser under the optimal operating current. The linewidth testing unit is also used to generate linewidth test results using the minimum integrated linewidth and the intrinsic linewidth at each injected current.

9. An electronic device, characterized in that, include: A memory, a processor, and a transceiver are sequentially connected in communication, wherein the memory is used to store computer programs, the transceiver is used to send and receive messages, and the processor is used to read the computer programs and execute the automatic testing method for narrow linewidth laser current linewidth as described in any one of claims 1 to 7.

10. A computer program product containing instructions, characterized in that, When the instructions are executed on the computer, the computer performs the automatic test method for narrow linewidth laser current linewidth as described in any one of claims 1 to 7.

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