Start-up control method and device for easy mode hopping laser

Abstract

The invention provides a start-up control method and device for an easy-mode-hopping laser, and relates to the technical field of lasers. The method comprises the steps of 1, responding to a starting instruction, and executing preliminary temperature control; step 2, acquiring the temperature value of the environment where the laser is located so as to determine a temperature control parameter strategy; step 3, executing secondary temperature control according to the temperature control parameter strategy; 4, third-time temperature control is executed; the device comprises a control module, a temperature control execution module and a temperature detection module. Based on this, after being started at different environment temperatures, the laser easy to jump modes can enter the central mode capable of outputting the central wavelength to work, so that the problem that an existing laser is difficult to stably work in the central wavelength mode after being started due to the starting advantage of a non-central mode is solved.

Description

Technical Field

[0001] This invention relates to the field of laser technology, specifically to a method and device for controlling the start-up of an easy-mode-jumping laser. Background Technology

[0002] Lasers are core optical emitting devices in fields such as optical communication, optical sensing, and precision measurement. The stability of their output wavelength directly determines the communication quality and sensing accuracy. For lasers, mode hopping upon startup is a key issue affecting the stability of their output wavelength. Specifically, some lasers (such as external cavity semiconductor lasers and narrow linewidth lasers) have multiple internal modes (longitudinal modes), each corresponding to a different output wavelength. There is overlap and mode competition between adjacent modes; the same temperature point may simultaneously correspond to two or three modes. This causes the laser to preferentially enter an undesired mode upon startup, resulting in a wavelength deviation from the desired wavelength. For example, if the internal temperature of the laser is directly controlled to the temperature corresponding to the center wavelength (desired wavelength) after power-on, and this temperature simultaneously corresponds to the center wavelength of the central mode and a non-central wavelength of the non-central mode, the laser may preferentially enter the non-central mode. The main reason is that the non-central mode has an advantage in terms of startup difficulty. Specifically, the non-central mode corresponding to the lower temperature range usually has lower resonant cavity loss and lower threshold current. Therefore, according to the principle of minimum energy, the laser will preferentially select the non-central mode with lower startup difficulty.

[0003] The current mainstream solution in the industry for addressing mode hopping during startup is screening, which involves detecting and eliminating lasers prone to mode hopping before deployment. For example, patent CN117030198A discloses a laser mode hopping detector and detection method. However, in practical applications, this approach leads to significant resource waste. Directly discarding lasers that are prone to mode hopping but whose core optoelectronic performance (such as output power and linewidth) still meets basic usage requirements results in a waste of raw materials and the human and material resources invested in production. Therefore, providing a control method that allows even lower-performance lasers to operate at their center wavelength after startup under various temperature conditions would significantly improve product yield and economic efficiency.

[0004] In summary, the present invention provides a method and apparatus for controlling the start-up of a laser that is prone to mode jumping, which can take advantage of the laser's non-central mode start-up and enable the laser to stably enter the central wavelength mode after startup. Summary of the Invention

[0005] The purpose of this invention is to provide a method and apparatus for controlling the start-up of a mode-hopping laser, in order to solve the problem mentioned in the background art, where existing lasers, due to their advantage of non-central mode start-up, are unable to stably operate in the central wavelength mode after startup.

[0006] This invention is achieved using the following technical solution: A method for controlling the power-on of a mode-hopping laser includes the following steps: Step 1: Respond to the power-on command and perform initial temperature control; In this step, the temperature is controlled to the preset temperature value corresponding to the center wavelength; Step 2: Obtain the ambient temperature of the laser to determine the temperature control parameter strategy; Step 3: Perform secondary temperature control according to the temperature control parameter strategy; In this step, the temperature is controlled to rise from the preset center wavelength temperature value to the rising point temperature value. Step 4: Perform temperature control three times; In this step, the temperature is controlled to drop from the rising point temperature value to the preset center wavelength temperature value or the actual center wavelength temperature value.

[0007] Furthermore, the preset center wavelength corresponding temperature value and the actual center wavelength corresponding temperature value are located within the temperature value range corresponding to the center mode of the laser; the rising point temperature value is ≥ the highest temperature value corresponding to the lower segment mode adjacent to the center mode and < the highest temperature value corresponding to the center mode.

[0008] The power-on control method for a mode-hopping laser provided by this invention establishes an adaptive dynamic temperature control strategy based on ambient temperature. Specifically: First, through preliminary temperature control, the laser temperature reaches the preset temperature value corresponding to the center wavelength. However, due to mode overlap and competition, the laser may be in the lower mode at this time. Then, through secondary temperature control, the temperature control parameter strategy is determined according to the ambient temperature, causing the laser temperature to rise to a temperature range exceeding the temperature range corresponding to the lower mode, thereby causing the laser to jump out of the lower mode and reach the center mode. Finally, through tertiary temperature control, the temperature of the laser in the center mode is reduced to return to the temperature value corresponding to the center wavelength, so that the laser can stably operate in the center mode and output a more accurate center wavelength after power-on.

[0009] Furthermore, in step 2, the temperature control parameter strategy is used to adjust the temperature control parameters, which include the temperature rise amplitude and / or the temperature rise rate.

[0010] Furthermore, the temperature control parameter strategy includes at least a first temperature control parameter, a second temperature control parameter, and a third temperature control parameter. The heating amplitude and / or heating rate in the first temperature control parameter is less than the heating amplitude and / or heating rate in the second temperature control parameter, which is less than the heating amplitude and / or heating rate in the third temperature control parameter. When the ambient temperature is less than or equal to a first preset temperature threshold, it is determined to be a low-temperature environment, and the first temperature control parameter is used. When the ambient temperature is greater than or equal to a second preset temperature threshold, it is determined to be a high-temperature environment, and the third temperature control parameter is used. When the first preset temperature threshold is less than or equal to a second preset temperature threshold, it is determined to be a normal temperature environment, and the second temperature control parameter is used.

[0011] Furthermore, the first preset temperature threshold is 10°C, and the second preset temperature threshold is 50°C.

[0012] In the above scheme, considering the variation of the effective tuning range of the laser modes under different ambient temperatures and the temperature regulation characteristics of the TEC, a temperature control parameter strategy is designed to ensure the effectiveness of secondary temperature control. Specifically, the effective tuning range here refers to the temperature regulation range in which the laser successfully jumps from the lower mode to the center mode without entering the upper mode after reaching the temperature value corresponding to the fixed preset center wavelength. Under high temperature conditions, the minimum and maximum temperatures corresponding to each mode will increase, so the upper and lower limits of this effective tuning range will increase. Conversely, under low temperature conditions, the upper and lower limits of this effective tuning range will decrease. The TEC temperature regulation characteristics include response delay and temperature overshoot, meaning that the TEC cannot instantly bring the laser to the target temperature value during temperature control, exhibiting a certain lag. Moreover, the actual temperature value may briefly exceed the target temperature value during heating and may briefly fall below the target temperature value during cooling, before gradually stabilizing. Therefore, in high-temperature environments, if the heating amplitude and / or heating rate during secondary temperature control is too small, the laser may not be able to jump out of the lower mode; in low-temperature environments, if the heating amplitude and / or heating rate is too large, the laser may overshoot and enter the upper mode.

[0013] Furthermore, the preset center wavelength corresponding temperature value and the actual center wavelength corresponding temperature value are equal or not equal; if they are not equal, the difference between the two is within the specified product tolerance range.

[0014] Furthermore, the preset center wavelength corresponding temperature value is determined based on the performance parameters of the laser, and it corresponds to different actual center wavelength corresponding temperature values ​​under different ambient temperature values.

[0015] In the above scheme, considering practical application, the preset center wavelength corresponding temperature value is generally taken as the actual center wavelength corresponding temperature value under normal temperature conditions. The actual center wavelength corresponding temperature value of the laser increases with the rise of ambient temperature. After performing three temperature control operations under extreme temperature conditions, it is preferable to bring the laser temperature to the actual center wavelength corresponding temperature value under the ambient temperature; alternatively, it can be brought back to the preset center wavelength corresponding temperature value. In this case, although there is a certain difference from the actual center wavelength corresponding temperature value, the slight wavelength difference caused by this difference is within the acceptable error range for the customer.

[0016] A laser mode-hopping laser start-up control device is provided to implement the above-described mode-hopping laser start-up control method. It includes a control module, a temperature control execution module, and a temperature detection module. The temperature control execution module and the temperature acquisition module are electrically connected to the control module. The temperature acquisition module is used to acquire the ambient temperature value of the laser. The temperature control execution module is used to perform temperature control. The control module is configured to generate a temperature control command and send it to the temperature control execution module, and to receive the ambient temperature value and determine the temperature control parameter strategy based on it.

[0017] Furthermore, the control module includes an electrically connected controller and a memory; the temperature control execution module includes an electrically connected digital-to-analog converter and a TEC drive circuit, the digital-to-analog converter being electrically connected to the controller.

[0018] The beneficial effects achieved by this invention are: This invention provides a method and apparatus for controlling the startup of a laser prone to mode hopping. By setting up a control module, a temperature control execution module, and a temperature detection module, and performing three adaptive temperature control steps based on ambient temperature, the laser can still enter a central mode capable of outputting the central wavelength after startup, even when facing the startup advantage of a non-central mode. Based on this, compared with existing technologies that use a screening and exclusion method, this invention effectively solves the problem of wavelength error after startup caused by mode competition, thereby improving the availability of lasers prone to mode hopping, significantly improving product yield, and reducing resource waste. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the steps of the mode-hopping laser power-on control method according to an embodiment of the present invention; Figure 2 This is a schematic diagram showing the correspondence between the modes of laser I described in this embodiment of the invention and temperature values ​​under low-temperature conditions; Figure 3 This is a schematic diagram showing the correspondence between the modes of laser I described in this embodiment of the invention and temperature values ​​under normal temperature conditions; Figure 4This is a schematic diagram showing the correspondence between the modes and temperature values ​​of the laser I described in this embodiment of the invention under high temperature conditions. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0021] The first aspect of this embodiment provides a power-on control device for an easy-mode-jumping laser, mainly including a control module, a temperature control execution module, and a temperature detection module, specifically: The temperature control execution module and the temperature acquisition module are electrically connected to the control module. The control module includes an electrically connected controller (MCU) and a memory. The temperature control execution module includes an electrically connected DAC digital-to-analog converter and a TEC drive circuit. The temperature acquisition module includes an ambient temperature sensor and a laser chip temperature sensor. The controller is electrically connected to the digital-to-analog converter, and the ambient temperature sensor and the laser chip temperature sensor are electrically connected to the controller.

[0022] The controller acts as the central control unit, coordinating the work of each module. It generates temperature control commands and sends them to the temperature control execution module. The memory stores the program code implementing the control method and pre-programs a library of laser characteristic parameters, calibrated during actual production. This library includes various target temperature values, temperature thresholds, and heating amplitudes and rates related to the control method. The controller can call the corresponding values ​​from the parameter library to generate the specific content in the temperature control command. A digital-to-analog converter (DAC) converts the digital temperature control commands sent by the controller into analog voltages. The TEC drive circuit generates a corresponding drive current based on this analog voltage, thereby controlling the heating or cooling of the thermoelectric cooler (TEC) and its power. An ambient temperature sensor collects the ambient temperature of the laser, while a laser chip temperature sensor collects the real-time internal temperature of the laser.

[0023] The second aspect of this embodiment provides a power-on control method for an easily mode-hopping laser, which utilizes the power-on control device described above. Please refer to [reference needed]. Figure 1 It includes the following steps: Step 1: Respond to the power-on command and perform initial temperature control. Specifically: After power-on, the controller first initializes by reading the preset temperature value corresponding to the center wavelength from the characteristic parameter library in the memory. This preset temperature value corresponding to the center wavelength is located within the temperature range corresponding to the center mode of the laser. Then, the controller uses this preset temperature value corresponding to the center wavelength as the target temperature value and generates a temperature control command to control the operation of the TEC drive circuit, thereby adjusting the laser temperature to the preset temperature value corresponding to the center wavelength. However, at this time, due to mode overlap and competition, the laser may enter the lower mode adjacent to the center mode.

[0024] Step 2: Obtain the ambient temperature of the laser to determine the temperature control strategy. Specifically: The controller reads the current ambient temperature value from an ambient temperature sensor, then compares this value with a preset temperature threshold to determine the current ambient temperature type, and based on this, determines the temperature control parameter strategy. The temperature control parameter strategy is used to adjust the temperature control parameters, which include the temperature rise amplitude and / or temperature rise rate. Wherein: The temperature control parameter strategy includes at least a first temperature control parameter, a second temperature control parameter, and a third temperature control parameter, wherein the temperature rise amplitude and / or temperature rise rate in the first temperature control parameter is less than the temperature rise amplitude and / or temperature rise rate in the second temperature control parameter, which is less than the temperature rise amplitude and / or temperature rise rate in the third temperature control parameter. The preset temperature threshold includes a first preset temperature threshold and a second preset temperature threshold, wherein the first preset temperature threshold is less than the second preset temperature threshold.

[0025] When the first preset temperature threshold is less than the ambient temperature and less than the second preset temperature threshold, the environment is considered normal temperature, and the second temperature control parameter is used. When the ambient temperature is less than or equal to the first preset temperature threshold, the environment is considered low temperature. Under the influence of the effective tuning range of the laser mode (the temperature regulation range in which the laser successfully jumps from the lower mode to the central mode without entering the upper mode after reaching a fixed preset center wavelength) and the TEC temperature regulation characteristics, to prevent the laser from jumping out of the central mode, the heating amplitude and / or heating rate need to be reduced, i.e., the first temperature control parameter is used. When the ambient temperature is greater than or equal to the second preset temperature threshold, the environment is considered high temperature. To prevent the laser from remaining in the lower mode, the heating amplitude and / or heating rate need to be increased, i.e., the third temperature control parameter is used.

[0026] Step 3: Execute secondary temperature control based on the determined temperature control parameters and strategy. Specifically: In this step, the temperature is controlled by appropriate temperature control parameters to rise from the preset center wavelength temperature value to the rising point temperature value, thereby causing the laser to exit the lower mode and enter the center mode. Specifically, the rising point temperature value is greater than or equal to the highest temperature value corresponding to the lower mode and less than the highest temperature value corresponding to the center mode.

[0027] Step 4: Perform temperature control three times. Specifically: In this step, the temperature of the laser in the central mode is controlled to decrease, from the rising point temperature value to either the preset center wavelength corresponding temperature value or the actual center wavelength corresponding temperature value. The actual center wavelength corresponding temperature value lies within the temperature range corresponding to the central mode. The preset center wavelength corresponding temperature value and the actual center wavelength corresponding temperature value may be equal or unequal; if they are unequal, the difference between them conforms to the specified product tolerance range. The preset center wavelength corresponding temperature value is determined based on the laser's performance parameters, and it corresponds to different actual center wavelength corresponding temperature values ​​under different ambient temperatures.

[0028] In this embodiment, taking a laser I with three modes (including the upper mode corresponding to the upper temperature range (high temperature), the center mode where the center wavelength is located, and the lower mode corresponding to the lower temperature range (low temperature)) as an example, specific values ​​are used to explain the relevant parameters in the above steps. Specifically: In this embodiment, the first preset temperature threshold is set to 10℃, the second preset temperature threshold is set to 50℃, and the temperature corresponding to the center wavelength under normal temperature conditions is set to the preset center wavelength temperature corresponding ... Table 1 Temperature values ​​under low temperature conditions (≤10℃)

[0029] Table 2 Temperature values ​​under normal temperature conditions (>10℃, <50℃)

[0030] Table 3 Temperature values ​​under high temperature conditions (≥50℃)

[0031] Based on Tables 1, 2, and 3 above, and in conjunction with... Figure 2 , Figure 3 and Figure 4 It can be known that: In step 1: the preset temperature value corresponding to the center wavelength is the temperature value corresponding to the center wavelength under normal temperature conditions, which is 22.3℃; In step 2: when the actual ambient temperature is ≤10℃, it is determined to be a low-temperature environment; when 10℃ < actual ambient temperature < 50℃, it is determined to be a normal-temperature environment; when the actual ambient temperature is ≥50℃, it is determined to be a high-temperature environment; where: If it is a low temperature environment, the lower limit of the effective tuning range is 22.9-22.3=0.6℃ and the upper limit is 23.6-22.3=1.3℃. Therefore, 0.6≤the temperature rise amplitude in the first temperature control parameter used is <1.3. If it is a normal temperature environment, the lower limit of the effective tuning range is 23.6-22.3=1.3℃ and the upper limit is 24.4-22.3=2.1℃. Therefore, 1.3≤the temperature rise amplitude in the first temperature control parameter used is <2.1. If it is a high-temperature environment, the lower limit of the effective tuning range is 24.5-22.3=2.2℃ and the upper limit is 25.1-22.3=2.8℃. Therefore, 2.2≤the temperature rise amplitude in the first temperature control parameter used is <2.8.

[0032] In step 3: Under different ambient temperatures, the laser temperature is controlled to rise from 22.3℃ to the rising point temperature value using the corresponding temperature control parameters obtained in step 2; specifically: If it is a low-temperature environment, then 22.9 ≤ the rising point temperature value < 23.6; If the environment is at room temperature, then 23.6 ≤ the rising point temperature value < 24.4; If it is a high-temperature environment, then 24.5 ≤ the rising point temperature value < 25.1.

[0033] In step 4: the laser temperature is controlled to decrease from the rising point temperature value until it reaches the temperature value corresponding to the preset center wavelength or the actual center wavelength; specifically: In low-temperature environments, the temperature can be lowered to 22.3℃ or 21.6℃; If the environment is at room temperature, the temperature will drop to 22.3℃; In high-temperature environments, the temperature can be reduced to 22.3℃ or 23℃.

[0034] In summary, this embodiment, by setting up a control module, a temperature control execution module, and a temperature detection module, and performing three adaptive temperature control steps based on ambient temperature, enables the laser to enter the center mode capable of outputting the center wavelength after power-on at different ambient temperatures. This avoids potential mode-hopping phenomena in the laser, allowing it to successfully enter the center wavelength mode after power-on. During subsequent operation, the laser's built-in temperature control module (e.g., a thermoelectric cooler, a common feature in the field) functions normally to cope with changes in ambient temperature during laser operation, thereby ensuring wavelength stability.

[0035] It should be noted that the parts not described in detail or in detail in the above solution are all existing technologies, such as how the controller performs control, the specific principle of the TEC drive circuit controlling the thermoelectric cooler, etc., which are not improvements made by this invention to the existing technology, nor are they within the protection scope of this invention's technical solution. Therefore, they will not be elaborated on in this article.

[0036] Of course, the above description is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the embodiments of the present invention. The present invention is also not limited to the above examples, and all equivalent changes and improvements made by those skilled in the art within the scope of the present invention should fall within the patent coverage of the present invention.

Claims

1. A method for controlling the start-up of a jumpable mode laser, characterized in that, The method comprises the following steps: Step 1: in response to a start-up instruction, performing a preliminary temperature control; In this step, the temperature is controlled to a preset central wavelength corresponding temperature value; Step 2: obtaining an ambient temperature value of the laser to determine a temperature control parameter strategy; Step 3: performing a secondary temperature control according to the temperature control parameter strategy; In this step, the temperature is controlled to rise from the preset central wavelength corresponding temperature value to a rising point temperature value; Step 4: performing a tertiary temperature control; In this step, the temperature is controlled to fall from the rising point temperature value to the preset central wavelength corresponding temperature value or an actual central wavelength corresponding temperature value.

2. The method of claim 1, wherein: The preset central wavelength corresponding temperature value and the actual central wavelength corresponding temperature value are located in a temperature value interval corresponding to a central mode of the laser; the rising point temperature value is greater than a highest temperature value corresponding to a lower mode adjacent to the central mode and less than a highest temperature value corresponding to the central mode.

3. The method of claim 1, wherein: In the step 2, the temperature control parameter strategy is used to adjust a temperature control parameter, and the temperature control parameter comprises a temperature rising amplitude and / or a temperature rising rate.

4. The easy-mode-jumping laser start-up control method according to claim 3, characterized in that: The temperature control parameter strategy comprises at least a first temperature control parameter, a second temperature control parameter and a third temperature control parameter, and a temperature rising amplitude and / or a temperature rising rate in the first temperature control parameter is less than that in the second temperature control parameter and that in the third temperature control parameter; When the ambient temperature value is less than or equal to a first preset temperature threshold, it is determined that the environment is low-temperature, and the first temperature control parameter is used; when the ambient temperature value is greater than or equal to a second preset temperature threshold, it is determined that the environment is high-temperature, and the third temperature control parameter is used; when the first preset temperature threshold is less than the ambient temperature value and the ambient temperature value is less than the second preset temperature threshold, it is determined that the environment is normal-temperature, and the second temperature control parameter is used.

5. The method of claim 4, wherein: The first preset temperature threshold is 10℃, and the second preset temperature threshold is 50℃.

6. The method of claim 2, wherein: The preset central wavelength corresponding temperature value and the actual central wavelength corresponding temperature value are equal or not equal; if not equal, a difference between the two values meets a product fault tolerance range.

7. The method of claim 6, wherein: The preset central wavelength corresponding temperature value is determined based on a performance parameter of the laser, and it corresponds to different actual central wavelength corresponding temperature values under different ambient temperature values.

8. A start-up control device for a mode-hop prone laser, for implementing the start-up control method for a mode-hop prone laser according to any one of claims 1 to 7, characterized in that: The control module, the temperature control execution module and the temperature detection module are electrically connected with the control module; The temperature detection module is used to obtain an ambient temperature value of the laser; the temperature control execution module is used to perform temperature control; and the control module is configured to generate a temperature control instruction and send it to the temperature control execution module, and receive the ambient temperature value and determine a temperature control parameter strategy based thereon.

9. The easy-jump laser start-up control device of claim 8, wherein: The control module comprises a controller and a memory electrically connected; and the temperature control execution module comprises a digital-to-analog converter and a TEC driving circuit electrically connected, and the digital-to-analog converter is electrically connected with the controller.

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