Laser temperature adjustment method and device

Abstract

This invention relates to the field of laser technology and discloses a method and apparatus for adjusting the temperature of a laser. The method includes: determining a second thermistor temperature based on a predetermined temperature compensation coefficient, a first ambient temperature, a second ambient temperature, and a first thermistor temperature, so that the temperature of the thermistor at the second ambient temperature is adjusted to the second thermistor temperature; wherein, the process of determining the temperature compensation coefficient in advance includes: performing wavelength change tests on a laser chip within a predetermined current range and at a first predetermined temperature to determine the corresponding wavelength change data of the laser chip; calculating the temperature compensation coefficient based on a first relationship between the laser chip wavelength and ambient temperature, the wavelength change data, the temperature tuning coefficient, and the test ambient temperature change data. This temperature compensation coefficient is thus introduced to offset the influence of ambient temperature fluctuations on the actual temperature of the laser chip, effectively improving the stability of the laser's output wavelength.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and in particular to a method and apparatus for adjusting the temperature of a laser. Background Technology

[0002] Semiconductor lasers, with their small size, high efficiency, low energy consumption, long lifespan, and direct tunability, are widely used in fields such as gas detection. The stability of the laser's output wavelength is one of the important indicators for evaluating laser performance.

[0003] In related technologies, the temperature is typically collected by a thermistor and fed back to a microprocessor. The microprocessor then uses a preset control algorithm to control the temperature control module based on the difference between this temperature and a preset temperature. This is used to eliminate the deviation between the temperature fed back by the thermistor and the preset temperature, thereby achieving stable control of the laser output wavelength.

[0004] Chinese invention patent application No. 201910058670.1 discloses a packaging method, a laser, and a gas detection device, specifically a semiconductor laser containing a TEC (Thermoelectric Cooler). This laser monitors the temperature of the semiconductor laser chip (LD (Laser Diode) chip) in real time using a thermistor and adjusts the temperature of the semiconductor laser chip via the cooler to control the laser's output wavelength. Chinese utility model patent application No. 202421623014.4 discloses a unidirectional temperature-controlled methane laser, specifically a unidirectional temperature-controlled semiconductor laser. It also monitors the temperature of the semiconductor laser chip (LD chip) in real time using a thermistor and adjusts the temperature of the semiconductor laser chip via a heating wire to control the laser's output wavelength.

[0005] However, in related technologies, due to the different positions of the thermistor and the laser chip, there is a certain difference between the temperature measured by the thermistor and the actual temperature of the chip, and this difference varies with the ambient temperature. In actual gas detection, the aforementioned temperature control method only maintains a constant temperature feedback from the thermistor. However, because of the temperature difference between the thermistor feedback temperature and the actual temperature of the laser chip, which changes with temperature, the laser output wavelength becomes unstable. In severe cases, this may cause the output wavelength of the laser under test to fail to lock onto the gas absorption peak, thus affecting the accuracy and reliability of the gas detection laser sensor. Summary of the Invention

[0006] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, this invention proposes a method, apparatus, computer device, and storage medium for adjusting the temperature of a laser. By introducing a temperature compensation coefficient, the influence of ambient temperature fluctuations on the actual temperature of the laser chip is offset, making the operating temperature of the laser chip more stable under different temperatures, thereby improving the stability of the laser's output wavelength.

[0007] To achieve the above objectives, a first aspect of the present invention provides a method for adjusting the temperature of a laser, the laser comprising a thermistor and a laser chip; the method comprising: determining a second thermistor temperature at the second ambient temperature based on a predetermined temperature compensation coefficient, a first ambient temperature, a second ambient temperature, and a first thermistor temperature at the first ambient temperature, so that the temperature of the thermistor at the second ambient temperature is adjusted to the second thermistor temperature; wherein the laser chip temperature at the first ambient temperature and the first thermistor temperature is the same as the laser chip temperature at the second ambient temperature and the second thermistor temperature;

[0008] The process of pre-determining the temperature compensation coefficient includes: performing wavelength change tests on the laser chip at a first preset temperature and within a preset current range to determine the wavelength change data corresponding to the laser chip; wherein the first preset temperature includes a fixed thermistor temperature and at least two test ambient temperatures selected within a preset ambient temperature range; the wavelength change data corresponds to test ambient temperature change data; and the temperature compensation coefficient is calculated based on a first relationship between the laser chip wavelength and ambient temperature, the wavelength change data, the temperature tuning coefficient corresponding to the laser chip, and the test ambient temperature change data.

[0009] According to one embodiment of the present invention, the step of calculating the temperature compensation coefficient based on a first relationship between the wavelength of the laser chip and the ambient temperature, the wavelength change data, the temperature tuning coefficient corresponding to the laser chip, and the test environment temperature change data includes: calculating the chip temperature change data corresponding to the laser chip based on the wavelength change data and the temperature tuning coefficient corresponding to the laser chip; and calculating the temperature compensation coefficient based on a second relationship between the laser chip temperature and the ambient temperature, the chip temperature change data, and the test environment temperature change data; wherein the first relationship is obtained based on the second relationship.

[0010] According to one embodiment of the present invention, the first relationship is represented as ,in, B represents the wavelength change of the laser chip; B represents the temperature tuning coefficient. This represents the change in ambient temperature; k is the temperature compensation coefficient.

[0011] According to one embodiment of the present invention, the first relationship is obtained based on a second relationship of laser chip temperature changing with ambient temperature; the second relationship is expressed as follows: ;in, This indicates the amount of temperature change in the laser chip.

[0012] According to one embodiment of the present invention, the second relationship is determined based on a third relationship between the temperature of the laser chip, the temperature of the thermistor, and the ambient temperature; the third relationship is denoted as T. c -T n =k(T n -T e )+c; where, T c T represents the temperature of the laser chip; n T represents the temperature of the thermistor; e c represents the ambient temperature; T represents the temperature of the thermistor. n With ambient temperature T e When they are equal, the temperature T of the laser chip is... c With respect to the temperature T of the thermistor n The difference between them.

[0013] According to one embodiment of the present invention, determining the second thermistor temperature under the second ambient temperature based on a predetermined temperature compensation coefficient, a first ambient temperature, a second ambient temperature, and a first thermistor temperature under the first ambient temperature includes: determining the second thermistor temperature according to the third relationship, the temperature compensation coefficient, the first ambient temperature, the second ambient temperature, and the first thermistor temperature.

[0014] According to one embodiment of the present invention, the first relationship is represented as ,in, B represents the wavelength change of the laser chip; B represents the temperature tuning coefficient. This represents the change in ambient temperature; the temperature compensation coefficient includes a. i n is the degree of the polynomial, and n is greater than 1.

[0015] According to one embodiment of the present invention, the first relationship is obtained based on a second relationship of laser chip temperature changing with ambient temperature; the second relationship is expressed as follows: ;in, This indicates the amount of temperature change in the laser chip.

[0016] According to one embodiment of the present invention, the second relationship is determined based on a third relationship between the temperature of the laser chip, the temperature of the thermistor, and the ambient temperature; the third relationship is expressed as follows: Among them, T c T represents the temperature of the laser chip; n T represents the temperature of the thermistor; e c represents the ambient temperature; T represents the temperature of the thermistor. n With ambient temperature T e When they are equal, the temperature T of the laser chip is... c With respect to the temperature T of the thermistor n The difference between them.

[0017] According to one embodiment of the present invention, the laser is used to detect a target gas; the step of performing a wavelength change test on the laser chip at a first preset temperature and within a preset current range to determine the wavelength change data corresponding to the laser chip includes: performing a wavelength change test on the laser chip at the first preset temperature and within the preset current range to determine the absorption peak position of the laser chip at the first preset temperature; obtaining the peak position current corresponding to the absorption peak position based on the absorption peak position and the maximum and minimum currents in the preset current range; calculating the peak position current change data based on the peak position current and a reference current in the preset current range; and calculating the wavelength change data based on the peak position current change data and the current tuning coefficient corresponding to the laser chip.

[0018] According to one embodiment of the present invention, the method for obtaining the current tuning coefficient includes: obtaining the output wavelength of the laser chip under at least two driving currents at a second preset temperature; wherein the second preset temperature includes a fixed thermistor temperature and a fixed ambient temperature; and calculating the current tuning coefficient based on the at least two driving currents and the output wavelengths corresponding to the at least two driving currents.

[0019] According to one embodiment of the present invention, the method for obtaining the temperature tuning coefficient includes: obtaining the output wavelength of the laser chip at at least two ambient temperatures under the conditions of fixed driving current and fixed thermistor temperature; and calculating the temperature tuning coefficient based on the at least two ambient temperatures and the output wavelengths at the at least two ambient temperatures.

[0020] To achieve the above objectives, a second aspect of the present invention provides a temperature adjustment device for a laser, the laser including a thermistor and a laser chip; the device includes: a thermistor temperature adjustment module, used to determine a second thermistor temperature at the second ambient temperature based on a predetermined temperature compensation coefficient, a first ambient temperature, a second ambient temperature, and a first thermistor temperature at the first ambient temperature, so that the temperature of the thermistor at the second ambient temperature is adjusted to the second thermistor temperature; wherein, the laser chip temperature at the first ambient temperature and the first thermistor temperature is the same as the laser chip temperature at the second ambient temperature and the second thermistor temperature;

[0021] The process of pre-determining the temperature compensation coefficient includes: performing wavelength change tests on the laser chip at a first preset temperature and within a preset current range to determine the wavelength change data corresponding to the laser chip; wherein the first preset temperature includes a fixed thermistor temperature and at least two test ambient temperatures selected within a preset ambient temperature range; the wavelength change data corresponds to test ambient temperature change data; and the temperature compensation coefficient is calculated based on a first relationship between the laser chip wavelength and ambient temperature, the wavelength change data, the temperature tuning coefficient corresponding to the laser chip, and the test ambient temperature change data.

[0022] According to various embodiments provided by the present invention, by introducing a temperature compensation coefficient, the influence of ambient temperature fluctuations on the actual temperature of the laser chip is offset, making the operating temperature of the laser chip more stable under different temperatures, thereby improving the stability of the laser's output wavelength. The temperature compensation coefficient is determined based on wavelength change data of the laser chip under a fixed thermistor temperature and different test ambient temperatures.

[0023] By establishing a quantitative relationship between changes in ambient temperature and changes in the wavelength characteristics of the laser chip, and combining this with the temperature tuning coefficient of the laser chip, the impact of ambient temperature changes on the actual operating temperature of the laser chip is derived in reverse, thus obtaining a temperature compensation coefficient. This coefficient is used to further construct a mathematical model of the dynamic relationship between ambient temperature, thermistor temperature, and laser chip temperature. Therefore, the interference of ambient temperature is effectively counteracted, and regardless of changes in ambient temperature, the stability of the laser chip's output wavelength can be ensured through the calibration of the thermistor temperature.

[0024] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0025] Figure 1aThis is a schematic diagram of the operating circuit of a temperature-controlled laser containing TEC, provided in the background section of this specification.

[0026] Figure 1b This is a schematic diagram of the working circuit of a unidirectional temperature-controlled laser provided in the background section of this specification.

[0027] Figure 1c This is a schematic diagram of the packaging structure of a TEC temperature-controlled semiconductor laser provided in the background section of this specification.

[0028] Figure 1d This is a schematic diagram of the packaging structure of a unidirectional temperature-controlled laser provided in the background section of this specification.

[0029] Figure 1e This is a schematic diagram of a thin-film circuit structure on an internal heat sink of a unidirectional temperature-controlled laser, provided in the background section of this specification.

[0030] Figure 1f This is a schematic flowchart of a laser temperature adjustment method provided according to an embodiment of this specification.

[0031] Figure 2 This is a schematic diagram of a process for determining a temperature compensation coefficient according to an embodiment of this specification.

[0032] Figure 3a This is a schematic diagram of a process for determining wavelength change data corresponding to a laser chip according to an embodiment of this specification.

[0033] Figure 3b This is a schematic diagram showing the positions of the absorption peaks at different ambient temperatures without temperature compensation for the thermistor, according to the embodiments provided in this specification.

[0034] Figure 3c A T provided according to the embodiments of this specification c -T n With T n -T e A diagram illustrating a linear relationship between them.

[0035] Figure 3d This is a schematic diagram showing the absorption peak positions of the thermistor under different ambient temperatures after temperature compensation, according to the embodiments provided in this specification.

[0036] Figure 4 This is a flowchart illustrating a method for precisely locking the output wavelength of a gas detection laser according to an embodiment of this specification. Detailed Implementation

[0037] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0038] Semiconductor lasers, with their small size, high efficiency, low energy consumption, long lifespan, and direct tunability, are widely used in fields such as gas detection. Taking gas detection as an example, according to Beer-Lambert's law, when detecting a target characteristic gas, the output wavelength of the semiconductor laser needs to be matched with the absorption peak of the target gas. The output wavelength of the laser is related to the temperature of the internal laser chip and the chip's operating current during emission. The typical temperature-dependent tuning factor for the laser wavelength is 0.1 nm / ℃, while the current must remain constant.

[0039] In related technologies, a packaging method, a laser, and a gas detection device are proposed. Specifically, a semiconductor laser containing a TEC (Thermoelectric Cooler) is proposed, which internally consists of a laser chip, a thermistor, a heat sink, and the TEC, among other components. (Reference) Figure 1a The diagram shown illustrates the working circuit of a temperature-controlled laser containing a TEC (Thermoelectric Temperature Regulator). Related technologies also propose a unidirectional temperature-controlled methane laser, specifically a unidirectional temperature-controlled semiconductor laser, internally composed of a laser chip, heat sink, heating resistor, thermistor, and other components. (Reference) Figure 1b The diagram shown is a schematic of the working circuit of a unidirectional temperature-controlled laser.

[0040] The working principle of the two types of lasers used for gas detection is as follows: the temperature of the laser chip collected by the thermistor is fed back to the microprocessor. The microprocessor (MCU) determines the control signal to be applied to the temperature control circuit or heating circuit based on the difference between this temperature and the preset temperature, using a preset control algorithm. This is done to adjust the cooling or heating power of the TEC, or to adjust the current, resistance, and energizing time of the heating resistor. In this way, the temperature of the thermistor is fed back to the TEC or heating resistor to control the laser to lock onto the characteristic output wavelength of the target gas. At this time, the output wavelength matches the absorption peak of the target gas, and the gas can be detected.

[0041] Meanwhile, in related technologies, TO (Transistor Outline) coaxial packaged semiconductor lasers are widely used in gas detection due to their simple packaging and low cost. TO lasers can be classified into TO46, TO56, etc., based on their socket size. (Reference) Figure 1cAs shown, the TEC temperature-controlled semiconductor laser internally encapsulates components such as the TEC, heat sink, laser chip, and thermistor; (Reference) Figure 1d As shown, a unidirectional temperature-controlled semiconductor laser internally encapsulates components such as a heat sink, laser chip, heating resistor, and thermistor. A key feature of unidirectional temperature-controlled lasers is the elimination of the TEC (thermal energy dispersive) device, allowing the use of smaller TO (thermal input) sockets and operation in a high-temperature range (60℃~70℃). (Reference) Figure 1e As shown, the unidirectional temperature-controlled laser has a thin-film circuit containing a heating resistor, a thermistor, and a chip built on an AIN (Aluminum Nitride) heat sink.

[0042] As shown in the diagram above, the thermistor and the laser chip are located in different positions, meaning there is a certain difference between the temperature measured by the thermistor and the actual temperature of the laser chip. In practical use, under different ambient temperatures (-10℃ to 60℃), whether it's a semiconductor laser with TEC (controlled at room temperature, e.g., 25℃) or a unidirectional temperature-controlled semiconductor laser (controlled at high temperature, e.g., 65℃), the laser output wavelength will shift, resulting in lower wavelength stability. In the field of gas detection, after the laser output wavelength shifts, it cannot match the absorption peak of the target gas. If there is a gas leak at this time, it will result in missed detection, affecting the accuracy of gas detection.

[0043] To improve the stability of laser output wavelength, it is necessary to propose a laser temperature adjustment method and device. The temperature adjustment method provided in this specification pre-determines a temperature compensation coefficient. Specifically, it applies a current within a preset range to the laser chip at a fixed thermistor temperature and different test ambient temperatures, performing wavelength change tests to measure and record the change data of the laser chip's emitted wavelength and the corresponding test ambient temperature change data. Under the first relationship between the laser chip wavelength and ambient temperature, the temperature compensation coefficient is calculated by combining the laser chip's temperature tuning coefficient with the obtained wavelength change data and test ambient temperature change data. In actual gas detection, based on the temperature compensation coefficient obtained according to the above method, and the first ambient temperature, second ambient temperature, and the first thermistor temperature collected at the first ambient temperature, a second thermistor temperature that the thermistor should reach at the second ambient temperature is calculated to determine the second thermistor temperature. The laser's temperature control module is then controlled to adjust the thermistor temperature to the second thermistor temperature, ensuring that the laser chip maintains the same operating temperature under different ambient temperatures.

[0044] Therefore, by introducing a temperature compensation coefficient, the influence of ambient temperature fluctuations on the actual temperature of the laser chip is offset, making the operating temperature of the laser chip more stable under different temperatures, thereby improving the stability of the laser's output wavelength. The temperature adjustment method provided in this manual is particularly suitable for high-precision detection scenarios such as gas detection. Taking a gas detection scenario as an example, if the temperature of the thermistor is controlled to reach the first thermistor temperature by the temperature control module under the first ambient temperature, the output wavelength of the laser matches the absorption peak of the target gas. When the ambient temperature is at a second ambient temperature, considering the influence of ambient temperature fluctuations on the actual temperature of the laser chip, the temperature adjustment method based on the temperature compensation coefficient can determine the actual temperature that the thermistor should reach. The temperature is then adjusted by controlling the temperature control module to compensate for the thermistor temperature, so that the actual temperature of the laser chip is the same as the laser chip temperature corresponding to the first ambient temperature and the first thermistor temperature. By stabilizing the chip temperature and avoiding detection errors caused by wavelength drift, the output wavelength of the gas detection laser can be guaranteed to match the absorption peak of the target gas under different temperatures, reducing the false alarm rate and improving the gas detection accuracy. The temperature adjustment method provided in this manual can also greatly enhance the adaptability of the laser to different environments, broadening its application scenarios.

[0045] This specification provides a method for adjusting the temperature of a laser, the laser including a thermistor and a laser chip; the temperature adjustment method includes: determining a second thermistor temperature at a second ambient temperature based on a predetermined temperature compensation coefficient, a first ambient temperature, a second ambient temperature, and a first thermistor temperature at the first ambient temperature, so that the temperature of the thermistor at the second ambient temperature is adjusted to the second thermistor temperature; wherein the laser chip temperature at the first ambient temperature and the first thermistor temperature is the same as the laser chip temperature at the second ambient temperature and the second thermistor temperature.

[0046] The process of pre-determining the temperature compensation coefficient may include the following steps:

[0047] The wavelength change of the laser chip is tested under a first preset temperature and within a preset current range to determine the corresponding wavelength change data of the laser chip; wherein, the first preset temperature includes a fixed thermistor temperature and at least two test environment temperatures selected within a preset ambient temperature range; the wavelength change data corresponds to the test environment temperature change data.

[0048] The temperature compensation coefficient is calculated based on the first relationship between the laser chip wavelength and the ambient temperature, the wavelength change data, the temperature tuning coefficient of the laser chip, and the ambient temperature change data.

[0049] Among them, lasers mainly refer to semiconductor lasers, whose output wavelength is affected by the operating temperature of the laser chip and the current applied to the laser chip.

[0050] The first relationship can be predetermined based on analysis, reasoning, or fitting of a large amount of data.

[0051] The temperature compensation coefficient can be used to describe the effect of ambient temperature changes on the temperature of the laser chip under the same thermistor temperature conditions, and can also be used to indirectly describe the effect of ambient temperature changes on the thermistor temperature under the same laser chip temperature conditions.

[0052] Thermistor temperature refers to the temperature obtained by measuring the temperature using the thermal effect of thermistors in a laser. In related technologies, thermistor temperature is approximately equivalent to the operating temperature of the laser chip.

[0053] The temperature tuning coefficient is the rate at which the output wavelength of a laser chip changes with ambient temperature.

[0054] Specifically, the temperature compensation coefficient of the laser is predetermined. First, the wavelength change of the laser chip is tested within a preset temperature and a preset current range to determine the corresponding wavelength change data. Specifically, by controlling the temperature of the laser's thermistor to remain at a fixed or stable temperature value, at least two ambient temperatures are selected as test ambient temperatures within a preset temperature range. At each test ambient temperature, a current within a preset current range is applied to the laser chip to obtain the output wavelength at different test ambient temperatures, thus performing the wavelength change test. This allows us to obtain the temperature change data between any two ambient temperatures, as well as the corresponding wavelength change data of the laser chip at those two ambient temperatures.

[0055] Alternatively, a reference ambient temperature and reference current can be predetermined, and the output wavelength of the laser at a fixed thermistor temperature, reference ambient temperature, and reference current can be used as the reference wavelength. The difference between the wavelength at each test ambient temperature and the reference wavelength is calculated to obtain wavelength variation data, and the difference between each test ambient temperature and the reference ambient temperature is calculated to obtain test ambient temperature variation data. The specific wavelength variation testing method can be determined based on the actual application scenario.

[0056] Based on the wavelength change data obtained from the test and the corresponding ambient temperature change data, as well as the first relationship between the laser chip wavelength and ambient temperature and the temperature tuning coefficient of the laser chip, a temperature compensation coefficient can be calculated. The first relationship includes the temperature compensation coefficient. Therefore, the temperature compensation coefficient can be used to describe the influence of ambient temperature changes on the laser chip temperature under the same thermistor temperature conditions, and further, it can be used to describe the influence of ambient temperature changes on the thermistor temperature under the same laser chip temperature conditions. This allows for the construction of a mathematical model of the dynamic relationship between ambient temperature, thermistor temperature, and laser chip temperature.

[0057] When the laser operates at the first ambient temperature, the temperature measured by the thermistor is the first thermistor temperature, and the corresponding laser chip temperature is denoted as the first chip temperature. When the laser operates at the second ambient temperature, to maintain the same output wavelength as the laser at the first ambient temperature and the first thermistor temperature, the second chip temperature of the laser chip at the second ambient temperature must be the same as the first chip temperature. Therefore, based on the predetermined temperature compensation coefficient, the first ambient temperature, the second ambient temperature, and the first thermistor temperature, the second thermistor temperature that the thermistor should reach at the second ambient temperature can be determined. Specifically, the second thermistor temperature is determined by calculation based on the temperature compensation coefficient, the relationship between the thermistor temperature and ambient temperature adjustment, the first ambient temperature, the second ambient temperature, and the first thermistor temperature. The relationship between the thermistor temperature and ambient temperature adjustment can also be predetermined based on analysis, reasoning, or fitting of a large amount of data.

[0058] The temperature of the second thermistor is used as the calibration temperature. Based on the temperature of the second thermistor, the temperature control module in the laser can be controlled to keep the thermistor at the second thermistor temperature under the second ambient temperature. This achieves temperature compensation of the thermistor, ensuring that the laser chip operates at the same temperature under different ambient temperatures, and ultimately ensuring that the output wavelength of the laser chip is the same under different ambient temperatures.

[0059] It should be noted that in this specification, the statement that the laser chip operates at the same temperature and output wavelength under different ambient temperatures means that the differences in operating temperature and output wavelength of the laser chip under different ambient temperatures are within a very small range.

[0060] For example, the thermistor of the laser is controlled to maintain a fixed temperature of 65°C, assuming a preset temperature range of -10°C to 60°C and a preset current range of 20mA to 60mA. At test ambient temperatures of -10°C, 0°C, 10°C, 20°C, 30°C, 40°C, 50°C, and 60°C, the output wavelength of the laser (i.e., the output wavelength of the laser chip) at different currents under each test ambient temperature can be measured. From this, the wavelength variation data under the same current at different test ambient temperatures can be calculated. Based on the first relationship between the laser chip wavelength and ambient temperature, the wavelength variation data, the temperature tuning coefficient of the laser chip, and the test ambient temperature variation data, multiple temperature compensation coefficients can be obtained. These coefficients can be further fitted using methods such as averaging or mode calculation to obtain the final temperature compensation coefficient.

[0061] Alternatively, assuming an ambient temperature of 25°C is used as the reference ambient temperature, the output wavelength of the laser is measured at an ambient temperature of 25°C, a thermistor temperature of 65°C, and a current of 30mA, and used as the reference wavelength. The output wavelength of the laser at different currents is measured at ambient temperatures of -10°C, 0°C, 10°C, 20°C, 30°C, 40°C, 50°C, and 60°C. The difference between each output wavelength and the reference wavelength is calculated to obtain wavelength variation data, and the difference between each test ambient temperature and the reference ambient temperature is calculated to obtain test ambient temperature variation data.

[0062] For example, the laser temperature adjustment method provided in this specification can be applied to the field of gas detection. Therefore, performing wavelength change testing on the laser chip within a first preset temperature and preset current range refers to performing target gas detection testing on the laser chip within the first preset temperature and preset current range. Specifically, this involves using a temperature cycling test (or high and low temperature test) method to conduct high and low temperature tests on the gas detection laser (e.g., a preset temperature range of -10°C to 60°C), controlling the thermistor temperature to be maintained at T... n The preset current range is I. low to I high In this example, the preset current range is also called the scan current range.

[0063] The thermistor of the laser is controlled to maintain a fixed temperature of 65℃. Assuming a preset temperature range of -10℃ to 60℃ and a preset current range of 20mA to 60mA, absorption waveform data of the laser within the scanning current range can be obtained at ambient temperatures of -10℃, 0℃, 10℃, 20℃, 30℃, 40℃, 50℃, and 60℃. Based on the absorption waveform data, the corresponding peak positions can be obtained. The wavelength variation data of the laser chip is determined by the shift in peak positions under different ambient temperatures.

[0064] The temperature compensation coefficient is calculated based on the first relationship between the laser chip wavelength and the ambient temperature, the wavelength change data, the temperature tuning coefficient of the laser chip, and the ambient temperature change data.

[0065] It should be noted that the laser temperature adjustment method provided in this manual can be applied to the laser control module (e.g., microcontroller MCU), and this method can also be applied to fields such as optical communication and laser sensing, without being specifically limited in this manual.

[0066] The fixed thermistor temperature, preset ambient temperature range, and preset current range in the first preset temperature can be determined according to the relevant parameters of the laser and the actual application scenario, etc., and are not specifically limited in this specification.

[0067] In some cases, when the laser is first put into use, refer to Figure 1f As shown, the laser temperature adjustment method may include:

[0068] S110. Perform wavelength change test on the laser chip under a first preset temperature and within a preset current range to determine the wavelength change data corresponding to the laser chip; wherein, the first preset temperature includes a fixed thermistor temperature and at least two test ambient temperatures selected within a preset ambient temperature range; the wavelength change data corresponds to the test ambient temperature change data.

[0069] S120. Based on the first relationship between the wavelength of the laser chip and the ambient temperature, the wavelength change data, the temperature tuning coefficient of the laser chip, and the ambient temperature change data, the temperature compensation coefficient is calculated.

[0070] S130. Based on a predetermined temperature compensation coefficient, a first ambient temperature, a second ambient temperature, and a first thermistor temperature under the first ambient temperature, determine a second thermistor temperature under the second ambient temperature, so as to control the temperature control module in the laser according to the second thermistor temperature; wherein, the laser chip temperature under the first ambient temperature and the first thermistor temperature is the same as the laser chip temperature under the second ambient temperature and the second thermistor temperature.

[0071] It should be noted that the predetermined temperature compensation coefficient refers to the temperature compensation coefficient being determined before the gas detection laser is officially put into actual gas detection work, and does not simply mean that the temperature compensation coefficient needs to be determined before each gas detection.

[0072] The preset current range, the fixed thermistor temperature in the first preset temperature, and the preset ambient temperature range can be determined according to the actual application scenario, etc.

[0073] In the above embodiments, by introducing a temperature compensation coefficient, the influence of ambient temperature fluctuations on the actual temperature of the laser chip is offset, and the temperature control strategy is dynamically adjusted to make the operating temperature of the laser chip more stable under different temperatures, thereby improving the stability of the laser's output wavelength. The temperature compensation coefficient is determined based on wavelength change data of the laser chip under different test ambient temperatures with a fixed thermistor temperature.

[0074] By establishing a quantitative relationship between changes in ambient temperature and changes in the wavelength characteristics of the laser chip, and combining this with the temperature tuning coefficient of the laser chip, the impact of ambient temperature changes on the actual operating temperature of the laser chip is derived in reverse, thus obtaining a temperature compensation coefficient. This coefficient is used to further construct a mathematical model of the dynamic relationship between ambient temperature, thermistor temperature, and laser chip temperature. Therefore, the interference of ambient temperature is effectively counteracted. Regardless of changes in ambient temperature, the laser chip can maintain a stable operating state by calibrating the thermistor temperature, achieving adaptive adjustment of the temperature control module. This significantly enhances the laser's adaptability to different environments, broadens its application scenarios, and is particularly suitable for high-precision detection scenarios such as gas detection.

[0075] Taking gas detection as an example, if the temperature of the thermistor is controlled to reach the first thermistor temperature by the temperature control module under the first ambient temperature, the output wavelength of the laser matches the absorption peak of the target gas. Under the second ambient temperature, considering the impact of ambient temperature fluctuations on the actual temperature of the laser chip, a temperature adjustment method based on a temperature compensation coefficient can be used to determine the actual temperature the thermistor should reach. The temperature is then adjusted by controlling the temperature control module to compensate for the thermistor temperature, ensuring that the actual temperature of the laser chip is the same as the corresponding laser chip temperature under the first ambient temperature and the first thermistor temperature. By stabilizing the chip temperature and avoiding detection errors caused by wavelength drift, the output wavelength of the gas detection laser can be guaranteed to match the absorption peak of the target gas under different temperatures, reducing the false negative rate and improving gas detection accuracy.

[0076] In some implementations, reference Figure 2 As shown, the temperature compensation coefficient is calculated based on the first relationship between the laser chip wavelength and ambient temperature, the wavelength change data, the temperature tuning coefficient of the laser chip, and the ambient temperature change data. This coefficient can include:

[0077] S210. Calculate the chip temperature change data corresponding to the laser chip based on the wavelength change data and the temperature tuning coefficient corresponding to the laser chip.

[0078] S220. Calculate the temperature compensation coefficient based on the second relationship between the laser chip temperature and the ambient temperature, the chip temperature change data, and the test environment temperature change data; wherein, the first relationship is obtained based on the second relationship.

[0079] The second relationship can be obtained in advance through analysis, reasoning, or fitting based on a large amount of data, and includes a temperature compensation coefficient.

[0080] Since there is a second relationship between the temperature change of the laser chip and the temperature change of the ambient temperature, and a certain relationship exists between the temperature change of the laser chip and the wavelength change of the laser chip, a first relationship between the wavelength change of the laser chip and the ambient temperature can be obtained based on this second relationship. Specifically, this first relationship is derived from the second relationship and the relationship between the wavelength change of the laser chip and the temperature change of the laser chip.

[0081] Specifically, the wavelength change of the laser chip With temperature change The following relationship exists between them: Where B represents the temperature tuning coefficient. Therefore, the wavelength change data obtained above and the temperature tuning coefficient corresponding to the laser chip can be used to calculate the chip temperature change data corresponding to the laser chip. Then, based on the second relationship between the laser chip temperature and the ambient temperature, the chip temperature change data, and the test environment temperature change data, the temperature compensation coefficient is calculated.

[0082] It should be noted that the temperature tuning coefficient can be obtained from parameters recorded in the laser's manual or other documents, or it can be obtained through relevant testing methods.

[0083] In some implementations, the first relation is represented as ,in, B represents the wavelength change of the laser chip; B represents the temperature tuning coefficient. This represents the change in ambient temperature; k is the temperature compensation coefficient.

[0084] Specifically, based on the aforementioned wavelength change data, the temperature tuning coefficient corresponding to the laser chip, and the ambient temperature change data corresponding to the wavelength change data, the pre-given first relationship between the laser chip wavelength and ambient temperature can be substituted into the data. The temperature compensation coefficient k is calculated.

[0085] In some implementations, the first relationship is obtained based on a second relationship between the laser chip temperature and the ambient temperature; the second relationship is expressed as follows: ;in, This indicates the amount of temperature change in the laser chip.

[0086] Specifically, the thermistor is a negative temperature coefficient (NTC) thermistor. The thermistor's resistance is controlled by the laser's temperature control module (e.g., the heating circuit in a unidirectional temperature-controlled laser), and the thermistor's temperature can be calculated from its resistance value.

[0087] Specifically, the wavelength change of the laser chip With temperature change Between Furthermore, the temperature change of the laser chip satisfies the second relationship with the temperature change of the ambient temperature. Combining these two relationships, we can deduce the first relationship between the laser chip wavelength and ambient temperature. .

[0088] Therefore, in some embodiments, when calculating the temperature compensation coefficient based on the first relationship of the laser chip wavelength changing with ambient temperature, the wavelength change data, the temperature tuning coefficient of the laser chip, and the test ambient temperature change data, the first relationship can be obtained by reasoning based on the second relationship mentioned above, and then the temperature compensation coefficient k can be obtained by calculation.

[0089] Alternatively, in other embodiments, when calculating the temperature compensation coefficient based on the first relationship between the laser chip wavelength and ambient temperature, wavelength change data, the temperature tuning coefficient corresponding to the laser chip, and the ambient temperature change data, the calculation can also be based on the wavelength change data, the temperature tuning coefficient corresponding to the laser chip, and... Calculations were performed to obtain the chip temperature change data corresponding to the laser chip. Then, based on the chip temperature change data, the test environment temperature change data, and... The temperature compensation coefficient k is obtained through calculation.

[0090] In some implementations, the second relationship is determined based on a third relationship between the temperature of the laser chip, the temperature of the thermistor, and the ambient temperature; the third relationship is denoted as T. c -T n =k(T n -T e )+c.

[0091] Among them, T c Indicates the temperature of the laser chip; T n The temperature of the thermistor is represented by T. e c represents the ambient temperature; T represents the temperature of the thermistor. n With ambient temperature T e When they are equal, the temperature T of the laser chip c With respect to the temperature T of the thermistor n The difference between them.

[0092] Specifically, the laser chip temperature T c With NTC thermistor temperature T n The difference between them, and the temperature T of the NTC thermistor n With ambient temperature T e The difference between them satisfies the linear relationship T c -T n =k(Tn -T e )+c.

[0093] At two different ambient temperatures T e1 and T e2 If the temperature of the laser's thermistor is kept at T... n Because the heat dissipation of the laser varies with different ambient temperatures, and the actual temperature of the laser chip is not exactly the same as the thermistor temperature, the ambient temperature T... e1 The laser chip temperature is T c1 Ambient temperature T e2 The laser chip temperature is T c2 Based on the above formula, we can derive: T c1 -T n =k(T n -T e1 )+c, and T c2 -T n =k(T n -T e2 Subtracting the two equations, we can obtain T. c1 -T c2 =k(T e2 -T e1 ).

[0094] The temperature difference T of the laser chip c1 -T c2 Recorded as and the temperature difference T between the ambient temperature e2 -T e1 Recorded as This allows us to derive the second relationship between the laser chip temperature and the ambient temperature. Furthermore, the first relationship between the laser chip wavelength and ambient temperature can be further deduced. .

[0095] Alternatively, the temperature difference T of the laser chip can be used. c1 -T c2 Recorded as and the temperature difference T between the ambient temperature e1 -T e2 Recorded as The resulting temperature compensation coefficient (denoted as k´) is then compared with the temperature difference T between the ambient temperature and the ambient temperature. e2 -T e1 Recorded as The signs of the temperature compensation coefficients calculated at that time are opposite.

[0096] It should be noted that the temperature compensation coefficient in this embodiment may have a different sign than the temperature compensation coefficient in the previous embodiments.

[0097] In some implementations, determining the second thermistor temperature under the second ambient temperature based on a predetermined temperature compensation coefficient, a first ambient temperature, a second ambient temperature, and the first thermistor temperature under the first ambient temperature may include: determining the second thermistor temperature according to a third relationship, the temperature compensation coefficient, the first ambient temperature, the second ambient temperature, and the first thermistor temperature.

[0098] Specifically, under the first and second ambient temperatures, it is necessary to keep the laser chip temperature constant to ensure that the laser's output wavelength remains constant. Therefore, under the premise that the laser chip temperature remains constant, according to the aforementioned third relationship T... c -T n =k(T n -T e The formula can be used to calculate the second thermistor temperature under the second ambient temperature by substituting the first ambient temperature, the second ambient temperature, and the first thermistor temperature under the first ambient temperature into the formula, along with the predetermined temperature compensation coefficient k.

[0099] It is understandable that, given the temperature compensation coefficient k, the value of c can be derived from a large number of known ambient temperatures and their corresponding thermistor temperatures.

[0100] For example, taking a gas detection laser as an example, in T e1 At the ambient temperature (corresponding to the first ambient temperature), the laser chip temperature is T. c The thermistor feedback temperature is T. n1 (Corresponding to the temperature of the first thermistor), at this point, the laser's output wavelength matches the absorption peak of the target gas. T e2 At the ambient temperature (corresponding to the second ambient temperature), to keep the output wavelength of the laser constant, the temperature of the laser chip must remain unchanged, i.e., it must still be T. c At this time, the feedback temperature of the thermistor should be T. n2 (Corresponding to the temperature of the second thermistor).

[0101] According to the aforementioned third relationship T c -T n =k(T n -T e ) + c, we can get: T c -T n1 =k(T n1 -T e1 )+c, and T c -T n2 =k(T n2 -T e2Subtracting the two equations, we can obtain the following relationship between the thermistor's temperature and the ambient temperature:

[0102]

[0103] Given the temperature compensation coefficient and the temperature T of the first thermistor. n1 First ambient temperature T e1 Second ambient temperature T e2 The temperature T of the second thermistor can be calculated. n2 Therefore, the temperature of the thermistor can be linearly compensated according to this formula. By changing the temperature control time or heating time, the output wavelength of the laser at the second ambient temperature can also be matched with the gas absorption peak.

[0104] In some implementations, the first relation is represented as ,in, B represents the wavelength change of the laser chip; B represents the temperature tuning coefficient. This represents the change in ambient temperature; the temperature compensation coefficient includes a. i n is the degree of the polynomial, and n is greater than 1.

[0105] Specifically, based on the aforementioned wavelength change data, the temperature tuning coefficient corresponding to the laser chip, and the ambient temperature change data corresponding to the wavelength change data, the pre-given first relationship between the laser chip wavelength and ambient temperature can be substituted into the data. The temperature compensation coefficient a is calculated. i .

[0106] In some embodiments, n takes the value of 2, then the first relation is represented as follows: The temperature compensation coefficients include a and b. When n is 2, a is the coefficient of the quadratic term a2 in the above polynomial expression, and b is the coefficient of the linear term a1 in the above polynomial expression.

[0107] It should be noted that the degree n of the polynomial can also be greater than 2. The higher the degree of the polynomial, the better the fitting effect. The specific value can be determined according to the actual application requirements.

[0108] In some implementations, the first relationship is obtained based on a second relationship between the laser chip temperature and the ambient temperature; the second relationship is expressed as follows: ;in, This indicates the amount of temperature change in the laser chip.

[0109] Specifically, the thermistor is an NTC thermistor.

[0110] Specifically, the wavelength change of the laser chip With temperature change Between Furthermore, the temperature change of the laser chip satisfies the second relationship with the temperature change of the ambient temperature. Combining these two relationships, we can deduce the first relationship between the laser chip wavelength and ambient temperature. .

[0111] In some embodiments, when calculating the temperature compensation coefficient based on the first relationship between the wavelength of the laser chip and the ambient temperature, the wavelength change data, the temperature tuning coefficient of the laser chip, and the ambient temperature change data, the first relationship can be derived by reasoning based on the second relationship described above, and then the temperature compensation coefficient a can be calculated. i .

[0112] In other embodiments, when calculating the temperature compensation coefficient based on the first relationship between the wavelength of the laser chip and the ambient temperature, the wavelength change data, the temperature tuning coefficient corresponding to the laser chip, and the ambient temperature change data, the calculation can also be based on the wavelength change data, the temperature tuning coefficient corresponding to the laser chip, and... Calculations were performed to obtain the chip temperature change data corresponding to the laser chip. Then, based on the chip temperature change data, the test environment temperature change data, and... Calculations are performed to obtain the temperature compensation coefficient 'a'. i .

[0113] For example, n takes the value 2, and the second relation is represented as Based on wavelength variation data, the temperature tuning coefficient of the laser chip, and... Calculations were performed to obtain the chip temperature change data corresponding to the laser chip. Then, based on the chip temperature change data, the test environment temperature change data, and... Calculations were performed to obtain the temperature compensation coefficients a and b.

[0114] In some implementations, the second relationship is determined based on a third relationship between the temperature of the laser chip, the temperature of the thermistor, and the ambient temperature; the third relationship is expressed as... .

[0115] Among them, T c Indicates the temperature of the laser chip; T n The temperature of the thermistor is represented by T. e c represents the ambient temperature; T represents the temperature of the thermistor. n With ambient temperature T e When they are equal, the temperature T of the laser chip c With respect to the temperature T of the thermistor n The difference between them.

[0116] In this embodiment, c is the same as T in the aforementioned embodiments. c -T n =k(T n -T e The 'c' in )+c is different.

[0117] Specifically, the laser chip temperature T c With NTC thermistor temperature T n The difference between them, and the temperature T of the NTC thermistor n With ambient temperature T e The difference between them satisfies a polynomial function relationship. At two different ambient temperatures T e1 and T e2 If the temperature of the laser's thermistor is kept at T... n Ambient temperature T e1 The laser chip temperature is T c1 Ambient temperature T e2 The laser chip temperature is T c2 The temperature difference T of the laser chip c1 -T c2 Recorded as and the temperature difference T between the ambient temperature e2 -T e1 Recorded as After multiple temperature cycling tests or high and low temperature experiments, a second relationship between the laser chip temperature and the ambient temperature can be approximately fitted. .

[0118] It should be noted that the temperature compensation coefficient 'a' in this embodiment... i The temperature compensation coefficient a in the aforementioned embodiments i The positive and negative values ​​may differ.

[0119] Furthermore, determining the temperature of the second thermistor under the second ambient temperature based on a predetermined temperature compensation coefficient, a first ambient temperature, a second ambient temperature, and the temperature of the first thermistor under the first ambient temperature may include: determining the temperature of the second thermistor according to a third relationship, the temperature compensation coefficient, the first ambient temperature, the second ambient temperature, and the temperature of the first thermistor.

[0120] For example, n takes the value 2, and the third relation is represented as T. c -T n =a(T n -T e ) 2 +b(T n -T e If )+c, then the sign of the temperature compensation coefficient b in this quadratic function relationship may be different from that of the temperature compensation coefficient b in the aforementioned embodiment.

[0121] Taking gas detection lasers as an example, in T e1 At the ambient temperature (corresponding to the first ambient temperature), the laser chip temperature is T. c The thermistor feedback temperature is T. n1 (Corresponding to the temperature of the first thermistor), at this point, the laser's output wavelength matches the absorption peak of the target gas. T e2 At the ambient temperature (corresponding to the second ambient temperature), to keep the output wavelength of the laser constant, the temperature of the laser chip must remain unchanged, i.e., it must still be T. c At this time, the feedback temperature of the thermistor should be T. n2 (Corresponding to the temperature of the second thermistor).

[0122] According to the third relation T c -T n =a(T n -T e ) 2 +b(T n -T e ) + c, we can get: T c -T n1 =a(T n1 -T e1 ) 2 +b(T n1 -T e1 )+c, and T c -T n2 =a(T n2 -T e2 ) 2 +b(T n2 -T e2 +c. Given the temperature compensation coefficient and the temperature T of the first thermistor. n1 First ambient temperature T e1 Second ambient temperature T e2 In this case, the temperature T of the second thermistor can be calculated. n2 Understandably, given the temperature compensation coefficients a and b, the value of c can be further derived from a large number of known ambient temperatures and their corresponding thermistor temperatures.

[0123] In some implementations, the laser is used to detect the target gas; see reference. Figure 3a As shown, wavelength change tests are performed on the laser chip within a first preset temperature and a preset current range to determine the corresponding wavelength change data of the laser chip, which may include:

[0124] S310. Perform wavelength change test on the laser chip at the first preset temperature and within the preset current range to determine the position of the absorption peak of the laser chip at the first preset temperature.

[0125] S320. Obtain the peak current corresponding to the absorption peak position based on the absorption peak position and the maximum and minimum currents within the preset current range.

[0126] S330. Calculate the peak current variation data based on the peak current and the reference current in the preset current range.

[0127] S340. Calculate the wavelength change data based on the peak current and the current tuning coefficient corresponding to the laser chip.

[0128] Peak current refers to the driving current value required to align the laser output wavelength with the center wavelength of the absorption peak of the target gas when driving the laser chip.

[0129] The reference current in the preset current range is a pre-determined current that corresponds to the laser's output wavelength matching the absorption peak of the target gas under specific temperature conditions (including thermistor temperature and ambient temperature).

[0130] The current tuning factor is the rate of change of the laser chip's output wavelength with the current.

[0131] In this embodiment, the laser is specifically a gas detection laser, and the fixed thermistor temperature in the first preset temperature can be determined according to the thermistor temperature corresponding to the laser output wavelength matching the absorption peak of the target gas at room temperature (e.g., 25°C).

[0132] Specifically, under normal circumstances, when a gas detection semiconductor laser is detecting a gas, the initial operating temperature of the laser can be set in the external circuit microprocessor (MCU). By collecting absorption waveform data and calculating the position of the absorption peak, it can be determined whether the absorption peak exists. If there is no absorption peak, the operating temperature of the laser is collected by a thermistor, and the thermistor temperature feedback is set to the TEC or heating resistor. The temperature control power is adjusted or the heating power is increased, and this cycle continues until the absorption peak appears.

[0133] Based on this principle, the temperature of the laser's thermistor can be set to a fixed value. At least two test ambient temperatures can be selected within a preset temperature range. At each test ambient temperature, the driving current of the laser chip is continuously adjusted within a given preset current range. Corresponding absorption waveform data is collected, and the position of the absorption peak under the corresponding temperature condition is calculated. This allows for wavelength change testing, obtaining the absorption peak position corresponding to the first preset temperature. The laser output wavelength corresponding to each absorption peak position is considered to be aligned with the center wavelength of the target gas absorption peak.

[0134] A reference current is determined within a preset current range. Under specific temperature conditions, the output wavelength of the laser at this reference current matches the absorption peak of the target gas. The peak position current corresponding to each absorption peak position can be calculated based on the positions of each absorption peak and the maximum and minimum currents within the preset current range. Since the wavelength of the laser chip changes with the current according to… ,in, This represents the wavelength change of the laser chip, and A represents the current tuning coefficient. This represents the change in current. Therefore, based on the peak current corresponding to each absorption peak position, the difference between each peak current and the reference current can be calculated, which is the peak current change data. Combined with the current tuning coefficient corresponding to the laser chip, the wavelength change data of the laser chip can be calculated.

[0135] In this embodiment, the wavelength change test can also be called the target gas detection test, high and low temperature test, or temperature cycling test.

[0136] For example, a high and low temperature test is conducted on a gas detection laser (the preset ambient temperature range is -10℃ to 60℃), and the scanning current range (i.e., the preset current range) is set to I. low to I high , will (I high -I low The driving current, denoted as I(I) / 2, corresponds to the center absorption wavelength of the laser, ensuring that the laser output wavelength matches the gas absorption peak. That is, the driving current at room temperature is controlled to be (I(I) / 2). high -I low When the wavelength of the laser is 1 / 2, the output wavelength of the laser matches the absorption peak of the target gas, and the temperature of the thermistor is T. n Keeping the thermistor temperature constant, select a test environment temperature within a preset range, and change the test environment temperature T. en Absorption waveform data within the scanning current range were collected at each test ambient temperature, and the absorption peak position at each test ambient temperature was calculated.

[0137] Then, according to I low +(I high -I low ) Calculate the peak current at each absorption peak position under various ambient temperatures. Based on the peak current, calculate the peak current I for each peak. i and(I high -I low The difference between ) / 2 By combining the current tuning coefficient A of the laser chip, the corresponding ambient temperature T can be obtained. i Wavelength variation value .

[0138] Furthermore, based on the temperature tuning coefficient B, we can obtain... The temperature difference of the laser chip can be obtained. Based on the third relation T c -T n =k(T n -T e )+c yields T c1 -T c2 =k(T e2 -T e1 ), that is, the second relation The value of the temperature compensation coefficient k can then be calculated as follows:

[0139]

[0140] Therefore, T can be derived. c -T n With T n -T e The functional relationship between them.

[0141] In particular, T c -T n With T n -T e The third relation between them can also satisfy the quadratic relation T. c -T n =a(T n -T e ) 2 +b(T n -T e )+c. Through multiple high and low temperature experiments, the second relationship can be approximately fitted and obtained as follows: And because By using the changes in peak current and ambient temperature after multiple changes in the test environment temperature, temperature compensation coefficients a and b can be obtained, thus establishing a clear quadratic relationship. Then, the temperature of the thermistor can be adjusted to match the laser's output wavelength with the target gas absorption peak.

[0142] For example, a high and low temperature test was conducted on the sensor module of a unidirectional temperature-controlled laser for methane detection. The laser output wavelength was controlled at 1653.7 nm at an ambient temperature of 25°C, at which point the thermistor temperature was 61.60°C. The scanning current range was set to 25~65 mA, where 45 mA is the driving current corresponding to the matching of the laser output wavelength with the absorption peak of methane at an ambient temperature of 25°C.

[0143] The thermistor temperature was maintained at 61.60℃. Absorption waveform data were collected at ambient temperatures of -10℃, 0℃, 10℃, 20℃, 30℃, 40℃, 50℃, and 60℃, and the corresponding shift in absorption peak position (center peak position is 0.5) was calculated for each ambient temperature. (Reference) Figure 3b As shown, without temperature compensation for the thermistor, the absorption peak positions at -10℃ to 60℃ are calculated to be 0.358, 0.397, 0.431, 0.467, 0.508, 0.55, 0.588, and 0.635, respectively.

[0144] The corresponding T temperature range is -10℃ to 60℃. n -T e The temperature differences between the thermistor and the ambient temperature were 71.6℃, 61.6℃, 51.6℃, 41.6℃, 31.6℃, 21.6℃, 11.6℃, and 1.6℃, respectively.

[0145] Based on 25mA + (65mA - 25mA) The absorption peak positions were determined, and the peak currents at various test ambient temperatures were calculated to be 39.32 mA, 40.88 mA, 42.24 mA, 43.68 mA, 45.32 mA, 47 mA, 48.52 mA, and 50.4 mA, respectively. The difference between each peak current and 45 mA was then calculated. .

[0146] Assuming the laser's current tuning coefficient is 0.02 mA / nm and its temperature tuning coefficient is 0.1 °C / nm, then we have and Based on the current difference at each peak This allows us to obtain the difference in laser output wavelength under the corresponding test ambient temperature (i.e., the difference from 1653.7nm), and the difference in laser chip temperature (i.e., the difference from the laser chip temperature under the conditions of ambient temperature of 25℃, thermistor temperature of 61.6℃, and driving current of 45mA). Furthermore, the value of the temperature compensation coefficient k in the linear relationship can be obtained.

[0147] Based on the above test data, the coefficient k is calculated to be 0.0317, T c -T n With T n -T e The relationship f(T) between them is satisfied n -T e Specifically, the linear relationship is as follows:

[0148] T c -T n =0.0317(T n-T e +1.167

[0149] refer to Figure 3c As shown, T c -T n With T n -T e A diagram illustrating a linear relationship between them. Based on the previously mentioned... The temperature of the thermistor can be linearly compensated according to changes in ambient temperature during actual use of the laser. For example, the heating power or heating time can be changed so that the output wavelength of the laser can still maintain a high matching rate with the gas absorption peak after the ambient temperature changes.

[0150] refer to Figure 3d The image shows the absorption peak positions measured at ambient temperatures of -10℃, 0℃, 10℃, 20℃, 30℃, 40℃, 50℃, and 60℃ after temperature compensation of the thermistor. This data was obtained through... Figure 3b and Figure 3d Comparison shows that after temperature compensation of the thermistor, the absorption peak positions at different ambient temperatures all exhibit only a small shift from the central peak position within 0.5 Å. Therefore, temperature compensation can maintain a high matching rate between the laser's output wavelength and the gas absorption peak at different ambient temperatures.

[0151] The temperature of the laser chip, the temperature of the thermistor, and the ambient temperature satisfy a third relationship. The description of the situation is similar to that described above, and will not be repeated here.

[0152] It should be noted that, in addition to using the center value of the preset current range as the driving current corresponding to the center absorption wavelength position of the laser, the current values ​​at other positions within the preset current range can also be used as the driving current corresponding to the center absorption wavelength position of the laser, for example (I high -I low ) / 3、(I high -I low ) 3 / 5, etc., can be determined based on actual application requirements.

[0153] In some embodiments, the current tuning coefficient may be obtained by: obtaining the output wavelength of the laser chip under at least two driving currents at a second preset temperature; wherein the second preset temperature includes a fixed thermistor temperature and a fixed ambient temperature; and calculating the current tuning coefficient based on the at least two driving currents and the output wavelengths corresponding to the at least two driving currents.

[0154] Specifically, keeping the temperature of the laser's thermistor and the ambient temperature constant, at least two different driving currents are applied to the laser chip. For each driving current, the corresponding output wavelength of the laser chip is measured and recorded. Based on the multiple sets of "driving current-output wavelength" data obtained from the test, the value of the current tuning coefficient can be calculated using methods such as linear fitting.

[0155] In some implementations, the temperature tuning coefficient may be obtained by: obtaining the output wavelength of the laser chip at at least two ambient temperatures under the conditions of fixed drive current and fixed thermistor temperature; and calculating the temperature tuning coefficient based on the at least two ambient temperatures and the output wavelengths at the at least two ambient temperatures.

[0156] Specifically, the temperature of the laser's thermistor and the driving current are kept constant while the ambient temperature is varied. For each ambient temperature, the corresponding output wavelength of the laser chip is measured and recorded. Based on multiple sets of "ambient temperature - output wavelength" data obtained from the tests, the temperature tuning coefficient can be calculated using methods such as linear fitting.

[0157] By way of example, based on the temperature adjustment method provided in this specification, this specification provides a method for precisely locking the output wavelength of a gas detection laser. (Reference) Figure 4 As shown, the output wavelength locking method mainly consists of four parts. The first and third parts are the methods for solving the current tuning coefficient and the temperature tuning coefficient. In the first part, when solving the current tuning coefficient, the ambient temperature of the laser and the temperature of the thermistor are kept constant, and the driving current of the laser is adjusted n times. The current value of each adjustment is recorded as I. i The value of i ranges from 1 to n, and the value of n is greater than or equal to 2. Data are collected from the laser at currents I1 to I... n The corresponding output wavelengths λ1 to λ n According to λ1-λ n =A (I1-I n ), which can fit the current tuning coefficient A of the laser under actual conditions.

[0158] In the third part, when solving for the temperature tuning coefficient, the laser's drive current and the thermistor temperature are kept constant, and the laser's ambient temperature is adjusted n times, with each adjustment temperature denoted as T. j The value of j ranges from 1 to n, and the value of n is greater than or equal to 2. Data are collected from the laser at ambient temperatures T1 to T... n The corresponding output wavelengths λ1 to λ n (λ1~λ here) n The λ1~λ collected in the first part above n (Different). According to λ1-λ n =B (T1-T n ), which can fit the temperature tuning coefficient B of the laser under actual conditions.

[0159] The second part describes the solution method for the temperature compensation relationship of the gas detection laser chip. High and low temperature tests are conducted on a gas detection laser (preset ambient temperature range: -10℃ to 60℃), and the thermistor temperature T is controlled. n The scanning current range remains unchanged at I. low ~I high The position of the central absorption peak corresponds to the current (I) high -I low ) / 2, varying ambient temperature ΔT e That is, changing the ambient temperature (-10℃~60℃) and acquiring the laser output waveform, recording the absorption peak positions (hereinafter referred to as peak positions) at each ambient temperature, and based on I low +(I high -I low ) Peak position, calculate the peak current at various ambient temperatures. It should be noted that 'n' in the above three parts of the process can be different.

[0160] Calculate the current at each peak position and (I) based on the current at each peak position. high -I low The difference between ) / 2 Combining the current tuning coefficient A calculated in the first part, the wavelength change value at the corresponding ambient temperature can be obtained. And, based on the temperature tuning coefficient B calculated in Part Three, the following is derived: The temperature difference of the laser chip can be obtained. .

[0161] And because of T c1 -T c2 =k(T e2 -T e1 ),Right now This allows us to obtain the value of k, and further, the value of T. c -T n With T n -T e The functional relationship between f(T) n -T e ).

[0162] Part Four describes the process of performing linear temperature compensation on the laser based on the functional relationship obtained in Part Two. According to the relationship f(T) n -T eTemperature compensation is performed by calculating the temperature that the thermistor should reach. Then, the duty cycle of the PWM (Pulse Width Modulation) wave is adjusted through a PID algorithm to change the on and off time of the MOSFET (Metal Oxide Semiconductor Field Effect Transistor). This, in turn, changes the voltage on / off time of the temperature control element, thereby altering the heating / cooling time of the temperature control element. This ensures that the laser's output wavelength matches the wavelength corresponding to the absorption peak of the gas, regardless of whether the temperature is low or high, achieving laser wavelength locking.

[0163] Considering that the heat dissipation efficiency of the laser varies under different ambient temperatures (e.g., -10℃, 0℃, 10℃, 20℃, etc.), and that a thermal field exists between the laser chip and the thermistor, there is a difference between the actual operating temperature of the laser chip and the temperature fed back by the thermistor (the industry default is that the laser chip operating temperature is the thermistor temperature). At a certain ambient temperature, the thermistor temperature is controlled to T using a temperature control circuit (TEC temperature control) or a heating circuit (unidirectional temperature control). n The laser chip temperature is T c At this point, the laser's output wavelength matches the absorption peak of the detected gas. Under another ambient temperature, if the thermistor temperature is still controlled to T by a temperature control circuit or heating circuit... n At this point, the actual operating temperature of the laser chip changed (became) This causes a shift in the laser's output wavelength. In gas detection scenarios, this wavelength shift due to changes in the actual operating temperature of the laser chip can lead to missed detections.

[0164] Therefore, addressing the issue of output wavelength shift in gas detection lasers under different ambient temperatures, resulting in mismatch with gas absorption peaks and the need to blindly adjust the thermistor temperature to find a matching wavelength without guidance, this specification proposes a method for precisely locking the output wavelength of gas detection lasers. Specifically, based on the functional relationship between the difference between the laser chip's operating temperature and the thermistor's temperature, and the difference between the thermistor's temperature and the ambient temperature, the thermistor's expected temperature is calibrated under different ambient temperatures. This calibration is then fed back to the temperature control module, which adjusts the output power or control time to regulate the thermistor's temperature feedback, maintaining a constant chip operating temperature. This ensures the laser's output wavelength does not shift, maintains a high degree of matching with the gas absorption peak, and reduces the output wavelength shift caused by changes in ambient temperature.

[0165] This specification also provides a temperature adjustment device for a laser, the laser including a thermistor and a laser chip; the temperature adjustment device may include: a thermistor temperature adjustment module, used to determine a second thermistor temperature under a second ambient temperature based on a predetermined temperature compensation coefficient, a first ambient temperature, a second ambient temperature, and a first thermistor temperature under the first ambient temperature, so that the temperature of the thermistor under the second ambient temperature is adjusted to the second thermistor temperature; wherein, the laser chip temperature under the first ambient temperature and the first thermistor temperature is the same as the laser chip temperature under the second ambient temperature and the second thermistor temperature.

[0166] The process of pre-determining the temperature compensation coefficient may include: performing wavelength change tests on the laser chip at a first preset temperature and within a preset current range to determine the corresponding wavelength change data of the laser chip; wherein the first preset temperature includes a fixed thermistor temperature and at least two test ambient temperatures selected within a preset ambient temperature range; the wavelength change data corresponds to the test ambient temperature change data; and the temperature compensation coefficient is calculated based on the first relationship between the laser chip wavelength and ambient temperature, the wavelength change data, the temperature tuning coefficient of the laser chip, and the test ambient temperature change data.

[0167] Specific limitations regarding the temperature adjustment device can be found in the limitations of the temperature adjustment method described above, and will not be repeated here. Each module in the aforementioned temperature adjustment device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of the computer device in hardware form or independent of it, or stored in the memory of the computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0168] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0169] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0170] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0171] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0172] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0173] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for adjusting the temperature of a laser, characterized in that, The laser includes a thermistor and a laser chip; the method includes: The temperature of a second thermistor under the second ambient temperature is determined based on a predetermined temperature compensation coefficient, a first ambient temperature, a second ambient temperature, and the temperature of a first thermistor under the first ambient temperature, so that the temperature of the thermistor under the second ambient temperature is adjusted to the temperature of the second thermistor; wherein, the laser chip temperature under the first ambient temperature and the first thermistor temperature is the same as the laser chip temperature under the second ambient temperature and the second thermistor temperature. The process of pre-determining the temperature compensation coefficient includes: The laser chip is subjected to wavelength change testing at a first preset temperature and within a preset current range to determine the corresponding wavelength change data of the laser chip; wherein, the first preset temperature includes a fixed thermistor temperature and at least two test ambient temperatures selected within a preset ambient temperature range; the wavelength change data corresponds to the test ambient temperature change data; The temperature compensation coefficient is calculated based on the first relationship between the wavelength of the laser chip and the ambient temperature, the wavelength change data, the temperature tuning coefficient corresponding to the laser chip, and the ambient temperature change data.

2. The method according to claim 1, characterized in that, The temperature compensation coefficient is calculated based on the first relationship between the laser chip wavelength and ambient temperature, the wavelength change data, the temperature tuning coefficient corresponding to the laser chip, and the ambient temperature change data. This calculation includes: The chip temperature change data corresponding to the laser chip is obtained by calculating based on the wavelength change data and the temperature tuning coefficient corresponding to the laser chip. The temperature compensation coefficient is calculated based on the second relationship between the laser chip temperature and the ambient temperature, the chip temperature change data, and the test environment temperature change data; wherein, the first relationship is obtained based on the second relationship.

3. The method according to claim 1, characterized in that, The first relationship is represented as ,in, B represents the wavelength change of the laser chip; B represents the temperature tuning coefficient. This represents the change in ambient temperature; k is the temperature compensation coefficient.

4. The method according to claim 3, characterized in that, The first relationship is obtained based on the second relationship of laser chip temperature changing with ambient temperature; the second relationship is expressed as follows: ;in, This indicates the amount of temperature change in the laser chip.

5. The method according to claim 4, characterized in that, The second relationship is determined based on a third relationship between the temperature of the laser chip, the temperature of the thermistor, and the ambient temperature; the third relationship is expressed as T. c -T n =k(T n -T e )+c; Among them, T c T represents the temperature of the laser chip; n T represents the temperature of the thermistor; e c represents the ambient temperature; T represents the temperature of the thermistor. n With ambient temperature T e When they are equal, the temperature T of the laser chip is... c With respect to the temperature T of the thermistor n The difference between them.

6. The method according to claim 5, characterized in that, The step of determining the temperature of the second thermistor under the second ambient temperature based on a predetermined temperature compensation coefficient, a first ambient temperature, a second ambient temperature, and the temperature of the first thermistor under the first ambient temperature includes: The temperature of the second thermistor is determined based on the third relationship, the temperature compensation coefficient, the first ambient temperature, the second ambient temperature, and the temperature of the first thermistor.

7. The method according to claim 1, characterized in that, The first relationship is represented as ,in, B represents the wavelength change of the laser chip; B represents the temperature tuning coefficient. This represents the change in ambient temperature; the temperature compensation coefficient includes a. i n is the degree of the polynomial, and n is greater than 1.

8. The method according to claim 7, characterized in that, The first relationship is obtained based on the second relationship of laser chip temperature changing with ambient temperature; the second relationship is expressed as follows: ;in, This indicates the amount of temperature change in the laser chip.

9. The method according to claim 8, characterized in that, The second relationship is determined based on a third relationship between the temperature of the laser chip, the temperature of the thermistor, and the ambient temperature; the third relationship is expressed as follows: ; Among them, T c T represents the temperature of the laser chip; n T represents the temperature of the thermistor; e c represents the ambient temperature; T represents the temperature of the thermistor. n With ambient temperature T e When they are equal, the temperature T of the laser chip is... c With respect to the temperature T of the thermistor n The difference between them.

10. The method according to claim 1, characterized in that, The laser is used to detect target gas; the wavelength change test of the laser chip at a first preset temperature and within a preset current range, to determine the wavelength change data corresponding to the laser chip, includes: The laser chip is subjected to wavelength change test at the first preset temperature and within the preset current range to determine the position of the absorption peak of the laser chip at the first preset temperature. The peak current corresponding to the absorption peak position is obtained based on the absorption peak position and the maximum and minimum currents in the preset current range. The peak current variation data is obtained by calculating based on the peak current and the reference current in the preset current range. The wavelength variation data is obtained by calculating based on the peak current variation data and the current tuning coefficient corresponding to the laser chip.

11. The method according to claim 10, characterized in that, The method for obtaining the current tuning coefficient includes: Obtain the output wavelength of the laser chip at at least two driving currents under a second preset temperature; wherein, the second preset temperature includes a fixed thermistor temperature and a fixed ambient temperature; The current tuning coefficient is calculated based on the at least two driving currents and the corresponding output wavelengths under the at least two driving currents.

12. The method according to any one of claims 1 to 11, characterized in that, The method for obtaining the temperature tuning coefficient includes: Under the conditions of fixed driving current and fixed thermistor temperature, the output wavelength of the laser chip at at least two ambient temperatures is obtained. The temperature tuning coefficient is calculated based on the at least two ambient temperatures and the corresponding output wavelengths at the at least two ambient temperatures.

13. A temperature adjustment device for a laser, characterized in that, The laser includes a thermistor and a laser chip; the device includes: A thermistor temperature adjustment module is used to determine a second thermistor temperature under the second ambient temperature based on a predetermined temperature compensation coefficient, a first ambient temperature, a second ambient temperature, and a first thermistor temperature under the first ambient temperature, so that the temperature of the thermistor under the second ambient temperature is adjusted to the second thermistor temperature; wherein, the laser chip temperature under the first ambient temperature and the first thermistor temperature is the same as the laser chip temperature under the second ambient temperature and the second thermistor temperature. The process of pre-determining the temperature compensation coefficient includes: The laser chip is subjected to wavelength change testing at a first preset temperature and within a preset current range to determine the corresponding wavelength change data of the laser chip; wherein, the first preset temperature includes a fixed thermistor temperature and at least two test ambient temperatures selected within a preset ambient temperature range; the wavelength change data corresponds to the test ambient temperature change data; The temperature compensation coefficient is calculated based on the first relationship between the wavelength of the laser chip and the ambient temperature, the wavelength change data, the temperature tuning coefficient corresponding to the laser chip, and the ambient temperature change data.

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