A method and device for screening the tuning range of a narrow linewidth laser

Abstract

The present application relates to a kind of narrow line width laser tuning range screening method and device, belong to optical fiber communication technical field;Method, comprising: step 1, linearly adjust the temperature of narrow line width laser, wavelength and optical power data are synchronously collected;Step 2, when detecting that optical power occurs mode jump, record the temperature-wavelength-power data before and after mode jump and reset;Step 3, in the temperature interval of mode jump, temperature step is refined using successive approximation method, and the maximum tuning wavelength value is positioned;Step 4, compare the measured tuning range with preset threshold, and output whether the qualified determination result;Device includes processor module, current control circuit, temperature control circuit, optical power detection circuit and wavelength detection module, complete screening device is constructed, current control, temperature control, optical power detection, wavelength detection and processing module are integrated, method to hardware closed loop is realized, support full-automatic screening, improve the operability of screening.

Description

Technical Field

[0001] This invention relates to a method and apparatus for screening the tuning range of a narrow linewidth laser, belonging to the field of optical fiber communication technology. Background Technology

[0002] In optical communication, narrow-linewidth lasers, besides needing to operate stably at the center wavelength, must also possess a certain wavelength tuning range for both upward and downward tuning when operating at the center wavelength. For example, Chinese Patent Publication No. CN116131096A discloses a wide-tunable narrow-linewidth semiconductor laser. It utilizes the Fano resonance between a microring resonator and a U-shaped waveguide, and the vernier caliper effect between the microring resonators to achieve tuning functionality. Furthermore, it employs a Mach-Zehnder interferometer to suppress side modes in the transmission spectrum of the microring resonator, improving wavelength selectivity. This achieves narrowed linewidth, frequency stability, and rapid tuning over a wide spectral range. Wavelength tuning is achieved by changing the internal temperature control of the narrow-linewidth laser. Within the same mode segment, tuning to the same wavelength in a narrow-linewidth laser corresponds to a unique temperature point. When a narrow-linewidth laser skips a mode, both its output power and wavelength will change. Therefore, the maximum tuning range of the narrow-linewidth laser is the wavelength value before the mode skip. To ensure the accuracy of optical communication, users need to screen the wavelength tuning range of narrow linewidth lasers.

[0003] Current wavelength tuning screening involves manually and gradually adjusting the temperature control value of the narrow-linewidth laser in the same direction until the laser exhibits mode-hopping. A wavelength meter is then used to observe the wavelength jump; the final wavelength before the jump represents the maximum up- or down-tuning range. Adjustments are then made in the opposite direction. This manual wavelength adjustment method is extremely resource-intensive and time-consuming.

[0004] Therefore, there is an urgent need for a method and device for screening the tuning range of narrow linewidth lasers, which can automatically screen out qualified narrow linewidth lasers and save manpower and resources. Summary of the Invention

[0005] The purpose of this invention is to provide a method and apparatus for screening the tuning range of narrow linewidth lasers. The method involves connecting the narrow linewidth laser to a control circuit, automatically capturing the maximum tuning value of the narrow linewidth laser, comparing it with tuning parameters, and finally screening out the qualified narrow linewidth lasers.

[0006] The present invention provides a method for screening the tuning range of a narrow linewidth laser, comprising:

[0007] Step 1: Linearly adjust the temperature of the narrow linewidth laser while simultaneously acquiring wavelength and optical power data;

[0008] Step 2: When mode hopping of optical power is detected, record the temperature-wavelength-power data before and after mode hopping and reset;

[0009] Step 3: Within the mode-hopping temperature range, refine the temperature step using a successive approximation method to locate the maximum tuning wavelength value;

[0010] Step 4: Compare the measured tuning range with the preset threshold and output the result of whether it is qualified.

[0011] By employing a process of linear temperature control, mode skipping detection, successive approximation positioning of the maximum tuning wavelength, and threshold comparison, the tuning range is automated and highly accurate, avoiding errors caused by manual intervention, improving screening efficiency and reliability, and saving manpower and resources.

[0012] Here, resetting means restarting the narrow-linewidth laser, returning the wavelength to its original center wavelength value.

[0013] Preferably, in step 1, the linear adjustment of the narrow linewidth laser temperature is specifically achieved by adjusting the temperature in steps ΔT = 0.5-1℃.

[0014] Setting the temperature step size to 0.5-1℃ (including 0.5℃ and 1℃) balances temperature control accuracy and efficiency: too large a step size may miss the jump point, while too small a step size will reduce efficiency. The 0.5-1℃ step size optimizes the efficiency of the screening process while ensuring data density.

[0015] Preferably, the determination condition for mode skipping in step 2 is:

[0016] The change in power |ΔP| ≥ ΔPmax,

[0017] The wavelength change |Δλ| ≥ Δλmax

[0018] After the wavelength jump, it falls within the non-edge tuning range of another mode segment;

[0019] Where ΔPmax is the allowable range of power variation, and Δλmax is the allowable range of wavelength variation.

[0020] The criteria for determining mode hopping (power / wavelength change exceeding the threshold and wavelength within the non-edge tuning range) have been clarified, avoiding misjudgments caused by accidental noise or unstable edge tuning, improving the accuracy of mode hopping detection, and providing a reliable basis for subsequent screening.

[0021] Preferably, step 2 specifically includes:

[0022] Step 201, Initialization

[0023] Create an empty list hops to store the locations of detected hop events;

[0024] Step 202: Traverse the data sequence

[0025] Starting from the second data point, i.e., index i = 1; compare the power and wavelength values ​​at the current time i with those at the previous time i-1;

[0026] Step 203: Calculate the change

[0027] Calculate the power change: |ΔP| = |current power - previous power|

[0028] Calculate the wavelength change: |Δλ| = |current wavelength - previous wavelength|

[0029] Step 204: Judgment of transition conditions

[0030] If both of the following conditions are met simultaneously, then mode skipping is considered to be possible:

[0031] Power jump: |ΔP| ≥ ΔPmax

[0032] Wavelength jump: |Δλ| ≥ Δλmax

[0033] Step 205: Non-edge range verification

[0034] Verify whether the current wavelength is within the non-edge range of normal tuning of the narrow linewidth laser. If the verification passes, add the current index i to the mode hopping list hops.

[0035] Step 206, Return Results

[0036] Finally, it returns a list of indexes of all detected hop events, hops.

[0037] Through a streamlined design that includes initialization, data traversal, change calculation, condition judgment, and non-edge verification, automatic detection and localization of mode-hopping events are achieved, reducing the complexity of manual analysis and improving the efficiency and consistency of mode-hopping detection.

[0038] Preferably, step 3 specifically includes:

[0039] Step 301: Find the upper limit of tuning

[0040] Coarse adjustment stage:

[0041] Starting from the current temperature Tstart, gradually increase the temperature ΔT and measure the wavelength λ;

[0042] If the wavelength continues to increase, record the current temperature Thigh and wavelength λhigh_temp.

[0043] When the wavelength stops increasing, stop coarse adjustment and start fine adjustment;

[0044] Fine-tuning stage:

[0045] Within the temperature range [Tlow, Thigh], calculate the intermediate temperature Tmid = (Tlow + Thigh) / 2;

[0046] Adjust to Tmid and measure wavelength λmid.

[0047] Adjust to Tmid+εtemp and measure λmid_plus.

[0048] If λmid_plus > λmid, it means that a larger wavelength exists in the direction of higher temperature, so update Tlow = Tmid; otherwise, update Thigh = Tmid.

[0049] Repeat until the temperature range difference is less than ε, at which point the wavelength corresponding to Thigh is λhigh;

[0050] Step 302: Find the lower limit of tuning

[0051] Similar to step 301, but the direction is to decrease the temperature and find the minimum wavelength;

[0052] Where ε represents precision.

[0053] The maximum tuning wavelength is located by a successive approximation method combining coarse and fine adjustment: coarse adjustment quickly narrows the range, while fine adjustment accurately approximates the limit temperature point through the bisection method, avoiding omissions or redundancies that may be caused by linear stepping, and significantly improving the accuracy and efficiency of tuning range positioning.

[0054] Preferably, the qualification determination in step 4 is as follows:

[0055] Calculation requirements: λupper = λcenter + Δ, λlower = λcenter – Δ;

[0056] If λhigh≥λupper and λlow≤λlower, then the tuning range is acceptable; otherwise, it is unacceptable.

[0057] Where λcenter is the center wavelength and Δ is the tuning range.

[0058] By directly comparing the preset tuning range (λcenter±Δ) with the measured range (λhigh / λlow), an objective and quantitative standard for qualification is provided, realizing the automated output of screening results and avoiding errors from subjective judgment.

[0059] The present invention provides a narrow linewidth laser tuning range screening device, comprising:

[0060] Current control circuit: used to control the power supply to the narrow linewidth laser and trigger a reset signal when mode skipping is detected;

[0061] Temperature control circuit: used for wavelength tuning control of narrow linewidth lasers;

[0062] Optical power detection circuit: used to acquire the output optical power of a narrow linewidth laser;

[0063] Wavelength detection module: used to acquire the current wavelength of the narrow linewidth laser in real time;

[0064] Processor module: Connects the current control circuit, temperature control circuit, optical power detection circuit and wavelength detection module, and is used to execute the above-mentioned narrow linewidth laser tuning range screening method to screen the narrow linewidth laser tuning range.

[0065] A complete screening device was constructed, integrating current control, temperature control, optical power detection, wavelength detection and processing modules, realizing a closed loop from method to hardware, supporting fully automatic screening, and improving the operability of screening.

[0066] Preferably, the processor module controls the switching of the narrow linewidth laser current by enabling the base level of the transistor in the current control circuit. When the narrow linewidth laser is turned off and then turned on again, it is combined with TEC temperature control to restore the narrow linewidth laser to the center wavelength value.

[0067] By controlling the base level of the transistor, the current of the narrow-linewidth laser is controlled to switch on and off. After reset, the narrow-linewidth laser automatically recovers its center wavelength, which simplifies the reset operation after mode skipping and improves the response speed and stability of the device.

[0068] Preferably, the processor module compares the actual operating temperature of the narrow-linewidth laser with the digital-to-analog converter of the temperature control circuit via an operational amplifier, and continuously adjusts the temperature control module of the narrow-linewidth laser to ensure that the operating temperature of the narrow-linewidth laser matches the control temperature.

[0069] By using a digital-to-analog converter and an operational amplifier to compare the actual temperature with the control temperature, closed-loop temperature control is achieved, ensuring precise and stable temperature of the narrow-linewidth laser, avoiding the impact of temperature fluctuations on the tuning range, and improving temperature control accuracy and screening reliability.

[0070] Preferably, the optical power detection circuit includes a photodiode and a transimpedance amplifier, which convert the output optical power of the narrow linewidth laser into a voltage signal and transmit it to the processor module.

[0071] The optical power detection circuit combining a photodiode and a transimpedance amplifier converts weak optical signals into voltage signals with a high signal-to-noise ratio, improving the sensitivity and accuracy of optical power detection and providing a reliable data basis for mode hopping determination.

[0072] Compared with existing technologies, the beneficial effects of the narrow linewidth laser tuning range screening method and apparatus of the present invention are as follows:

[0073] 1. Significantly improved screening accuracy and reliability

[0074] Accurate identification of mode hopping events: By setting power change thresholds (ΔPmax) and wavelength change thresholds (Δλmax), combined with verification of non-edge tuning range, false judgments are effectively filtered out, ensuring that recording is triggered only when mode hopping occurs, avoiding false detections caused by noise or temporary fluctuations.

[0075] Precise positioning of tuning boundaries: The temperature step is refined within the mode skipping range by adopting the successive approximation method. The temperature range is dynamically narrowed through two stages of coarse and fine adjustment. Finally, the maximum / minimum tuning wavelength is located with high precision ε. Compared with the traditional linear scanning method, this method can reduce the number of measurement points and improve the accuracy of boundary positioning.

[0076] 2. Optimization of screening efficiency and automation level

[0077] Linear adjustment and synchronous acquisition: Through step temperature adjustment and real-time data acquisition (step 1), continuous monitoring of the tuning process is achieved, avoiding intermittent errors caused by manual intervention.

[0078] The reset mechanism ensures stability: after mode hopping occurs, the system automatically resets to the center wavelength (step 2) to ensure that subsequent measurements are not affected by the previous mode hopping and to improve test repeatability.

[0079] 3. Product quality control and cost reduction

[0080] Threshold comparison judgment: The measured tuning range is directly compared with the preset threshold (λcenter±Δ) to quickly output a qualified / unqualified conclusion, avoiding subjective judgment and ensuring that the tuning performance of the factory-delivered narrow linewidth laser meets the design requirements.

[0081] Integrated device design: The processor module coordinates current control, temperature control, optical power and wavelength detection to achieve full automation of the screening process, reduce manual operation time and equipment dependence, and reduce production costs.

[0082] 4. Hardware and Algorithm Co-optimization

[0083] Temperature control closed loop: A temperature control loop is constructed using a digital-to-analog converter and an operational amplifier to ensure that the actual temperature is consistent with the set value, thereby improving the stability of temperature adjustment.

[0084] High-sensitivity optical power detection: The combination of photodiode and transimpedance amplifier converts the optical signal into a voltage signal, enhancing the detection capability of weak optical power changes and supporting the sensitivity of mode hopping determination.

[0085] In summary, this technical solution, through algorithm optimization and hardware integration, solves the problems of low accuracy, poor efficiency, and excessive human interference in traditional screening methods, providing an efficient and reliable quality control means for the large-scale production of narrow-linewidth lasers. Attached Figure Description

[0086] Figure 1 This is a structural block diagram of a narrow linewidth laser tuning range screening device according to the present invention;

[0087] Figure 2 This is a circuit diagram of a current control circuit according to the present invention;

[0088] Figure 3 This is a circuit diagram of a temperature control circuit according to the present invention;

[0089] Figure 4 This is a circuit diagram of an optical power detection circuit according to the present invention;

[0090] Figure 5 This is a flowchart illustrating the operation of a narrow linewidth laser tuning range screening device according to the present invention. Detailed Implementation

[0091] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0092] Example 1

[0093] like Figures 1-4 As shown, this embodiment discloses a narrow linewidth laser tuning range screening device, comprising:

[0094] Current control circuit: A MOSFET driving circuit is used. The gate voltage of MOSFET Q1 is a fixed value, that is, the driving current of the narrow linewidth laser is a unique fixed value. During reset, the narrow linewidth laser is turned off by pulling down the base level of transistor Q2. After power-on, the laser is restored to the center wavelength value by combining TEC temperature control.

[0095] Temperature control circuit: Includes PID control module and TEC cooling chip, outputs control voltage through 16-bit DAC, drives TEC through operational amplifier U3, with an accuracy of ±0.01℃.

[0096] Optical power detection circuit: 1 / 100 of the output light is split and fed into photoelectric converter PD1. The current is then converted into voltage and fed into ADC analog-to-digital converter for voltage acquisition. The processor calculates the optical power value based on the ADC acquisition value.

[0097] Wavelength detection module: A computer is used to obtain the current wavelength of the narrow linewidth laser in real time via a wavelength meter.

[0098] Processor module: It adopts the STM32H743 main control chip, runs the FreeRTOS real-time operating system, and sets the sampling frequency to 10kHz; it communicates with the computer via wired or wireless communication to determine whether the narrow linewidth laser generates mode hopping, so as to capture the final wavelength tuning maximum value of the narrow linewidth laser.

[0099] like Figure 5 As shown, the working process of this narrow linewidth laser tuning range screening device is as follows:

[0100] 1. The processor module can control the on / off state of the narrow linewidth laser through the current control circuit. After the narrow linewidth laser generates mode skipping, it resets the narrow linewidth laser. The processor controls the operating temperature of the narrow linewidth laser through the temperature controller, thereby controlling the wavelength tuning of the narrow linewidth laser and finding the maximum tuning range of the wavelength.

[0101] 2. The processor module detects the optical power of the narrow-linewidth laser via the optical detection module. Within the same mode band, the output power of a narrow-linewidth laser changes smoothly with wavelength adjustment. However, when mode hopping occurs, the power of the narrow-linewidth laser experiences a relatively drastic jump. At this point, it is determined whether the wavelength tuning during mode hopping is greater than or equal to the required tuning range. In the center wavelength region of a narrow-linewidth laser, the gain medium achieves the highest power output near the center wavelength. For example, a 1550nm tunable narrow-linewidth laser can achieve an output power of 10.0dBm-13.0dBm at the center wavelength. When the wavelength deviates from the center to the edge of the gain bandwidth, the gain coefficient of the narrow-linewidth laser decreases significantly, leading to power attenuation. After mode hopping, the wavelength of the narrow-linewidth laser will fall within the non-edge tuning range of another mode band, and the power of the narrow-linewidth laser will undergo a drastic increase.

[0102] Table 1 Correspondence between wavelength and power variation

[0103] 1 24.5 1550.5600 12.95 2 25.5 1550.5605 12.20 3 26.4 1550.5610 11.45 4 27.5 1550.5615 10.7 5 28.6 1550.5621 9.17 6 29.4 1550.5585 (resulting in membrane skipping) 11.85 (Power reverses sharply)

[0104] It can be seen that the narrow linewidth laser exhibits mode skipping between 28.6℃ and 29.4℃. The processor will then refine this range to find the operating temperature point for mode skipping.

[0105] 3. The processor iteratively approaches the temperature point where the maximum wavelength tuning value of the narrow-linewidth laser is found. The processor informs the computer that this is the maximum tuning wavelength value of the narrow-linewidth laser. The computer records this value and compares it with the required maximum tuning wavelength value to determine if it meets the requirements. For example, if the center wavelength of the narrow-linewidth laser is λ1 = 1540.56 nm, and the required tuning range is ±0.05 nm, then the upper and lower tuning ranges of the narrow-linewidth laser should be greater than 1540.61 nm and less than 1540.51 nm, respectively. If the wavelength tuning range of the narrow-linewidth laser is 1540.60 nm - 1540.52 nm, then the tuning range of the narrow-linewidth laser is unacceptable. If the wavelength tuning range of the narrow-linewidth laser is 1540.62 nm - 1540.50 nm, then the tuning range of the narrow-linewidth laser is acceptable.

[0106] 4. After finding the wavelength tuning range on one side, repeat steps 1, 2, and 3 above to find out whether the maximum wavelength tuning value on the other side (upward or downward tuning) meets the standard.

[0107] Example 2

[0108] This embodiment discloses a method for screening the tuning range of a narrow linewidth laser, including:

[0109] Step 1: Linearly adjust the temperature of the narrow linewidth laser while simultaneously acquiring wavelength and optical power data;

[0110] Step 2: When mode hopping of optical power is detected, record the temperature-wavelength-power data before and after mode hopping and reset;

[0111] Step 3: Within the mode-hopping temperature range, refine the temperature step using a successive approximation method to locate the maximum tuning wavelength value;

[0112] Step 4: Compare the measured tuning range with the preset threshold and output the result of whether it is qualified.

[0113] Specifically as follows:

[0114] 1. Data Acquisition and Preprocessing

[0115] Data is acquired in real time using an optical power detection circuit and a wavelength meter.

[0116] 2. Threshold setting

[0117] Set ΔPmax and Δλmax according to the narrow linewidth laser datasheet, and define the mode boundary (e.g., 1550.55nm to 1550.57nm is one mode).

[0118] 3. Jump Detection Algorithm

[0119] 3.1 Initialization

[0120] Create an empty list hops to store the locations of detected hop events;

[0121] 3.2 Traversing the Data Sequence

[0122] Starting from the second data point, i.e., index i = 1; compare the power and wavelength values ​​of the current time i with those of the previous time i-1; the step temperature ΔT between the current time i and the previous time i-1 is 1℃;

[0123] 3.3 Calculate the change

[0124] Calculate the power change: |ΔP| = |current power - previous power|

[0125] Calculate the wavelength change: |Δλ| = |current wavelength - previous wavelength|

[0126] 3.4 Jump Condition Judgment

[0127] If both of the following conditions are met simultaneously, then mode skipping is considered to be possible:

[0128] Power jump: |ΔP| ≥ ΔPmax

[0129] Wavelength jump: |Δλ| ≥ Δλmax

[0130] 3.5 Non-edge range verification

[0131] Verify whether the current wavelength is within the non-edge range of normal tuning of the narrow linewidth laser. If the verification passes, add the current index i to the mode hopping list hops.

[0132] 3.6 Return Results

[0133] Finally, it returns a list of indexes of all detected hop events, hops.

[0134] Code example:

[0135] defdetect_mode_hop(power_series,wavelength_series,delta_p,delta_lambda):

[0136] hops=[]

[0137] foriinrange(1,len(power_series)):

[0138] dp=abs(power_series[i]-power_series[i-1])

[0139] dl=abs(wavelength_series[i]-wavelength_series[i-1])

[0140] ifdp>=delta_panddl>=delta_lambda:

[0141] #Verify whether it is in the non-edge tuning range

[0142] ifis_non_edge(wavelength_series[i]):

[0143] hops.append(i)

[0144] returnhops

[0145] 4. Tuning range verification and adjustment

[0146] After mode hopping, calculate the deviation between the current wavelength and the target tuning range.

[0147] If the deviation exceeds the allowable range, the temperature control module (TEC) refines the search for a stable operating point within the mode skipping range using smaller steps (e.g., 0.1℃). Specifically:

[0148] 4.1 Initialization Parameters

[0149] Inputs: center wavelength λcenter, tuning range Δ, initial temperature adjustment step size ΔTinitial, accuracy ε;

[0150] Output: Maximum wavelength λhigh, minimum wavelength λlow;

[0151] 4.2 Finding the upper limit of tuning

[0152] Coarse adjustment stage:

[0153] Starting from the current temperature Tstart, gradually increase the temperature ΔTinitial and measure the wavelength λ;

[0154] If the wavelength continues to increase, record the current temperature Thigh and wavelength λhigh_temp.

[0155] When the wavelength stops increasing, stop coarse adjustment and start fine adjustment;

[0156] Fine-tuning stage:

[0157] Within the temperature range [Tlow, Thigh], calculate the intermediate temperature Tmid = (Tlow + Thigh) / 2;

[0158] Adjust to Tmid and measure wavelength λmid.

[0159] Adjust to Tmid+εtemp and measure wavelength λmid_plus.

[0160] If λmid_plus > λmid, it means that a larger wavelength exists in the direction of higher temperature, so update Tlow = Tmid; otherwise, update Thigh = Tmid.

[0161] Repeat until the temperature range difference is less than ε, at which point the wavelength corresponding to Thigh is λhigh;

[0162] 4.3 Finding the lower limit of tuning

[0163] Similar to 4.2, but the direction is to reduce the temperature and find the minimum wavelength.

[0164] 5. Conformity verification

[0165] Calculation requirements: λupper = λcenter + Δ, λlower = λcenter – Δ;

[0166] If λhigh ≥ λupper and λlow ≤ λlower, then the tuning range is acceptable; otherwise, it is unacceptable.

[0167] For example

[0168] Input: λcenter=1540.56nm, Δ=0.05nm, ΔTinitial=0.5°C, ε=0.01°C.

[0169] Output:

[0170] If λhigh = 1540.62nm (≥ 1540.61nm) and λlow = 1540.50nm (≤ 1540.51nm), then it is acceptable.

[0171] If λhigh = 1540.60nm (< 1540.61nm) and λlow = 1540.52nm (> 1540.51nm), then it is unqualified.

[0172] The above description is only a preferred embodiment of this practice, but the scope of protection of this embodiment is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the scope of the technology disclosed in this embodiment, based on the technical solution and inventive concept of this embodiment, should be covered within the scope of protection of this embodiment.

Claims

1. A method for screening the tuning range of a narrow linewidth laser, characterized in that, include: Step 1: Linearly adjust the temperature of the narrow linewidth laser while simultaneously acquiring wavelength and optical power data; Step 2: When mode hopping of optical power is detected, record the temperature-wavelength-power data before and after mode hopping and reset; Step 3: Within the mode-hopping temperature range, refine the temperature step using a successive approximation method to locate the maximum tuning wavelength value; Step 3 specifically includes: Step 301: Find the upper limit of tuning Coarse adjustment stage: Starting from the current temperature Tstart, gradually increase the temperature ΔT and measure the wavelength λ; If the wavelength continues to increase, record the current temperature Thigh and the wavelength λhigh_temp; When the wavelength stops increasing, stop coarse adjustment and start fine adjustment; Fine-tuning stage: Within the temperature range [Tlow, Thigh], calculate the intermediate temperature Tmid = (Tlow + Thigh) / 2, where Tlow represents the minimum value of the temperature range and Thigh represents the maximum value of the temperature range. Adjust to Tmid and measure wavelength λmid; Adjust to Tmid+εtemp, and measure λmid_plus; If λmid_plus > λmid, it means that a larger wavelength exists in the direction of higher temperature, so update Tlow = Tmid; otherwise, update Thigh = Tmid. Repeat until the temperature range difference is less than ε, at which point the wavelength corresponding to Thigh is λhigh; Step 302: Find the lower limit of tuning Similar to step 301, but the direction is to decrease the temperature and find the minimum wavelength λlow; Where ε represents precision; Step 4: Compare the measured tuning range with the preset threshold and output the result of whether it is qualified. The qualification determination in step 4 is as follows: Calculation requirements: λupper = λcenter + Δ, λlower = λcenter – Δ; If λhigh≥λupper and λlow≤λlower, then the tuning range is acceptable; otherwise, it is unacceptable. Where λcenter is the center wavelength and Δ is the tuning range.

2. The method of claim 1, wherein the laser is a narrow linewidth laser. In step 1, the linear adjustment of the narrow linewidth laser temperature is specifically achieved by adjusting the temperature in steps of ΔT = 0.5-1℃.

3. The method of claim 1, wherein the laser is a narrow linewidth laser. The determination condition for mode skipping in step 2 is as follows: The change in power |ΔP| ≥ ΔPmax, The wavelength change |Δλ| ≥ Δλmax After the wavelength jump, it falls within the non-edge tuning range of another mode segment; Where ΔPmax is the allowable range of power variation, and Δλmax is the allowable range of wavelength variation.

4. The method for screening the tuning range of a narrow linewidth laser according to claim 3, characterized in that, Step 2 specifically includes: Step 201, Initialization Create an empty list hops to store the locations of detected hop events; Step 202: Traverse the data sequence Starting from the second data point, i.e., index i=1; compare the power and wavelength values ​​at the current time i with those at the previous time i-1; Step 203: Calculate the change Calculate the power change: |ΔP| = |current power - previous power| Calculate the wavelength change: |Δλ| = |current wavelength - previous wavelength| Step 204: Judgment of transition conditions If both of the following conditions are met simultaneously, then mode skipping is considered to be possible: Power jump: |ΔP| ≥ ΔPmax Wavelength jump: |Δλ| ≥ Δλmax Step 205: Non-edge range verification Verify whether the current wavelength is within the non-edge range of normal tuning of the narrow linewidth laser. If the verification passes, add the current index i to the mode hopping list hops. Step 206, Return Results Finally, it returns a list of indexes of all detected hop events, hops.

5. A narrow linewidth laser tuning range screening device, characterized in that, include: Current control circuit: used to control the power supply to the narrow linewidth laser and trigger a reset signal when mode skipping is detected; Temperature control circuit: used for wavelength tuning control of narrow linewidth lasers; Optical power detection circuit: used to acquire the output optical power of a narrow linewidth laser; Wavelength detection module: used to acquire the current wavelength of the narrow linewidth laser in real time; Processor module: Connects current control circuit, temperature control circuit, optical power detection circuit and wavelength detection module, used to execute the narrow linewidth laser tuning range screening method according to any one of claims 1-4, and to screen the narrow linewidth laser tuning range.

6. The narrow linewidth laser tuning range screening device according to claim 5, characterized in that, The processor module controls the switching of the narrow linewidth laser current by adjusting the base level of the transistor in the enable current control circuit. When the narrow linewidth laser is turned off and then turned on again, it will return to the center wavelength value.

7. The narrow linewidth laser tuning range screening device according to claim 5, characterized in that, The processor module compares the actual operating temperature of the narrow-linewidth laser with the digital-to-analog converter of the temperature control circuit via an operational amplifier, and continuously adjusts the temperature control module of the narrow-linewidth laser to ensure that the operating temperature of the narrow-linewidth laser matches the control temperature.

8. The narrow linewidth laser tuning range screening device according to claim 5, characterized in that, The optical power detection circuit includes a photodiode and a transimpedance amplifier, which convert the output optical power of the narrow linewidth laser into a voltage signal and transmit it to the processor module.

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