Quantum cascade laser chip temperature acquisition method and system

Abstract

The invention relates to the technical field of lasers, in particular to a quantum cascade laser chip temperature acquisition method and system. The method comprises the following steps: mounting at least one temperature sensor on one side, close to a light emitting junction of a laser, of a heat sink, collecting real-time temperature values through the temperature sensor, preprocessing the plurality of temperature values, and calculating the real-time temperature of the laser based on a plurality of first temperature values obtained after preprocessing through a moving average method. According to the method, a high-precision temperature sensor is mounted close to a quantum cascade laser chip, so that the problem of monitoring lag of the chip temperature due to the fact that an existing quantum cascade laser tube core temperature detector is far away from a luminous junction is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of lasers, and particularly to a method and system for collecting the temperature of a quantum cascade laser chip. Background Art

[0002] A quantum cascade laser is a unipolar semiconductor laser based on intersubband electron transitions within the conduction band. The quantum cascade laser adopts a multi-stage series structure and requires high voltage and large current injection during operation. However, its electro-optical conversion efficiency is relatively low, resulting in Joule heat generation at the light-emitting junction. As the temperature of the light-emitting junction increases, the threshold current of the laser increases correspondingly, causing the output wavelength of the laser to change and reducing the output stability of the laser. Therefore, active cooling is usually required for the quantum cascade laser. Active cooling actively conducts the redundant heat of the laser to keep its temperature within the error range. However, accurate temperature acquisition is required for active cooling to accurately feedback the temperature of the laser, so that the heat conduction amount of active cooling can be adjusted in a timely manner according to the real-time temperature of the laser. Therefore, the present application provides a method and system for collecting the temperature of a quantum cascade laser chip to accurately collect the temperature of the laser. Summary of the Invention

[0003] The object of the present invention is to: in view of the technical problem that the temperature control method of active cooling in the prior art requires accurate temperature acquisition to achieve accurate adjustment of the heat conduction amount, through the embodiments of the present application, a method and system for collecting the temperature of a quantum cascade laser chip are provided, which realizes high-precision acquisition of the laser temperature and is beneficial to improving the heat conduction efficiency of the active cooling method.

[0004] To achieve the above-mentioned invention object, the present invention provides the following technical solutions: A method for collecting the temperature of a quantum cascade laser chip, comprising: Mounting at least one temperature sensor on one side of the heat sink close to the light-emitting junction of the laser, collecting real-time temperature values through the temperature sensor, preprocessing the plurality of temperature values, and calculating the real-time temperature of the laser based on the plurality of first temperature values obtained after the preprocessing by the moving average method.

[0005] As a preferred technical solution of the present application, the temperature sensor is mounted on the side of the heat sink where the light-emitting junction and the heat sink solder joint are located.

[0006] As a preferred technical solution of the present application, the temperature sensor is mounted at a position close to the light-emitting junction and close to the heat sink solder joint.

[0007] As a preferred technical solution of the present application, the temperature sensor and the heat sink are connected by thermal conductive silver paste.

[0008] As a preferred technical solution of the present application, the temperature sensor and the heat sink are connected by the thermal conductive silver glue under hot pressing conditions.

[0009] As a preferred technical solution of the present application, the preprocessing includes: calculating the average value of the temperature values at multiple positions at the same moment as the first temperature value.

[0010] As a preferred technical solution of the present application, the preprocessing further includes: calculating the ratio of the temperature value at the same position at multiple moments to the corresponding time change amount to obtain a temperature change rate; calculating the standard deviation of the temperature change rates at multiple positions, and calculating the average value of the temperature values with the standard deviation less than or equal to a preset first threshold to obtain the first temperature value.

[0011] As a preferred technical solution of the present application, the preprocessing further includes: constructing a correction function based on the temperature values with the standard deviation less than or equal to the preset first threshold; using the correction function to correct the temperature values with the standard deviation greater than the first threshold.

[0012] As a preferred technical solution of the present application, the temperature sensor is set as a platinum resistance PT1000.

[0013] A quantum cascade laser chip temperature acquisition system provided by the present application includes: One or more processors; A memory, on which one or more programs are stored. When the one or more programs are executed by the one or more processors, the one or more processors implement the acquisition and preprocessing of temperature data in the described quantum cascade laser chip temperature acquisition method.

[0014] Compared with the prior art, the beneficial effects of the present invention are: In the present application, a high-precision platinum resistance is mounted near the light-emitting junction of the quantum cascade laser die, which solves the problem that the existing temperature detector of the quantum cascade laser die is far from the light-emitting junction, has a large thermal resistance, and there is a serious lag in chip temperature detection; the temperature test point is closer to the heat generation power point, the thermal resistance is smaller, and the acquired temperature value is closer to the working temperature of the laser, which is beneficial to improving the real-time performance of temperature monitoring and realizing high-precision monitoring of the temperature of the quantum cascade chip. Description of the Drawings

[0015] Figure 1 It is a flowchart for mounting the platinum resistance; Figure 2 It is a physical structure schematic diagram after the platinum resistance is mounted; Figure 3 It is a schematic flow diagram for the platinum resistance to collect and calculate the real-time temperature; Figure 4Schematic diagram of the process for collecting the real-time temperature of the laser Detailed implementation mode

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention.

[0017] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents some embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0018] It should be noted that, without conflict, the embodiments in the present invention and the features and technical solutions in the embodiments may be combined with each other.

[0019] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0020] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use, or the orientation or positional relationship commonly understood by those skilled in the art. Such terms are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive distinction and should not be construed as indicating or implying relative importance.

[0021] For example Figures 1 - 4 As shown, a method for collecting the temperature of a quantum cascade laser chip provided in this embodiment collects the temperature by mounting a PT1000 platinum resistor at a position close to the light-emitting junction of the quantum cascade laser. Specifically, it includes: mounting at least one temperature sensor on one side of the heat sink close to the laser light-emitting junction. The mounting step, for example Figure 1 As shown, includes: First step, shape the pins of the platinum resistor PT1000 and clean the platinum resistor. The pins of the temperature detector can be directly welded to the pins of the laser housing, which is convenient for the subsequent application of the quantum cascade laser chip and has great versatility and flexibility.

[0022] Second step, for example Figure 2As shown, select the side of the heat sink where the light-emitting junction and the heat sink soldering point are located as the preferred mounting area. Apply highly thermally conductive thermal silver glue to the mounting area of the platinum resistance near the quantum cascade laser under a high-magnification microscope to improve the bonding firmness.

[0023] In the third step, mount the platinum resistance PT1000 within the mounting area of the quantum cascade laser. Preferably, mount the temperature sensor at a position close to the light-emitting junction and close to the heat sink soldering point to minimize the distance for the laser temperature to conduct to the temperature sensor as much as possible. Apply pressure to the temperature sensor to ensure firm and reliable mounting.

[0024] In the fourth step, place the quantum cascade laser with the mounting completed into a high-precision high-temperature baking oven and cure the thermal silver glue under a specific temperature change curve. The quantum cascade laser after mounting the platinum resistance PT1000 is as shown Figure 2 in the figure.

[0025] Mounting a high-precision platinum resistance near the light-emitting junction of the quantum cascade laser die solves the problem that the existing temperature detector of the quantum cascade laser die is far from the light-emitting junction, has a large thermal resistance, slow heat conduction, and causes a serious lag in the detection of the chip temperature; the temperature test point is closer to the heat generation power point, has a smaller thermal resistance, and the collected temperature value is closer to the operating temperature of the laser, which is beneficial to improving the real-time performance of temperature monitoring and realizes high-precision monitoring of the temperature of the quantum cascade chip.

[0026] In one embodiment, the platinum resistance PT1000 is connected to the ADC single-chip microcomputer, and the method for collecting the real-time temperature is the three-wire constant current source driving method. The process of a single platinum resistance PT1000 collecting the real-time temperature is as shown Figure 3 in the figure. Directly measure the original voltage across the platinum resistance PT1000 sensor. After amplifying the signal of the original voltage through an amplifier such as AD620, output it to the ADC single-chip microcomputer together with a constant current. Calculate the amplified resistance value through the amplified voltage and the constant current, and finally calculate the ratio of the amplified resistance value to the gain factor of the amplifier to obtain the real-time resistance value of PT1000. Based on the approximate linear relationship between the resistance and temperature of the platinum thermal resistance, the ADC single-chip microcomputer obtains the corresponding real-time temperature of the platinum resistance PT1000.

[0027] In this embodiment, the ADC single-chip microcomputer converts the resistance value into the temperature value T through the formula in the Callendar-Van Dusen equation where the temperature is greater than 0 °C. The conversion formula is: ; where, R Tis the resistance value obtained by measuring PT1000; R0 is the resistance value of PT1000 at 0 °C; A and B are constants measured by the sensor manufacturer through experiments, or constants from the standard of industrial platinum resistance temperature sensors. In this embodiment, the IEC-60751 international standard is adopted, where A is 3.9083 × 10 -3 , and B is -5.775 × 10 -7 .

[0028] Obtain the real-time temperature values collected by the temperature sensor and preprocess multiple said temperature values. In a preset time sliding window, calculate the real-time temperature of the laser based on multiple first temperature values obtained after the preprocessing by the moving average method.

[0029] The method of the preprocessing includes: calculating the average value of the temperature values at multiple positions at the same moment as the first temperature value. At the same time, in order to reduce the interference of abnormal temperature values, it also includes calculating the ratio of the temperature values at multiple moments at the same position to the time change amount of multiple moments to obtain the temperature change rate. Calculate the standard deviation of the temperature change rates at multiple positions respectively, which is used to reflect the fluctuation of the temperature collected by the temperature sensor. When the fluctuation is large, it indicates that there is an abnormality in the temperature range collected by the temperature sensor. At this time, if the standard deviations of other temperature sensors are also large, it indicates that the stability of the output of the laser has decreased, and the inspection of the laser status should be stopped; if the fluctuations of other temperature sensors are normal, it indicates that this temperature sensor is abnormal.

[0030] Therefore, for example Figure 4 as shown, further calculate the average value of multiple said temperature values whose standard deviation is less than or equal to a preset first threshold to obtain the first temperature value.

[0031] In a further embodiment, it also includes correcting multiple said temperature values whose standard deviation is greater than the first threshold. Obtain multiple said temperature values and / or the first temperature value whose standard deviation is less than or equal to a preset first threshold, and fit these data by the polynomial fitting method to obtain a temperature fitting function. In a specific embodiment, this application constructs a polynomial based on the temperature values of platinum resistance PT1000 at multiple positions at their respective multiple moments; based on the approximate linear relationship between the temperature and resistance value of platinum resistance PT1000, the order of the polynomial is set to 2, and the corresponding polynomial formula is: ; Wherein, t is time; a0, a1, and a2 are coefficients to be solved, and are solved by the least squares method based on the temperature values of the platinum resistor PT1000 at multiple moments. Obtain the platinum resistor PT1000 corresponding to the standard deviation greater than the first threshold, and use the obtained polynomial formula to correct its temperature value based on the initial value of the platinum resistor PT1000. Recalculate the standard deviation for the corrected temperature value, and eliminate the temperature values of the platinum resistor PT1000 corresponding to the standard deviation still greater than the first threshold. Calculate the first temperature value based on the temperature values with the corrected standard deviation less than or equal to the first threshold and the temperature values of other platinum resistors PT1000.

[0032] The above embodiments are only used to illustrate the present invention and do not limit the technical solutions described in the present invention. Although this specification has described the present invention in detail with reference to the above respective embodiments, the present invention is not limited to the above specific embodiments. Therefore, any modification or equivalent replacement to the present invention; and all technical solutions and their improvements that do not depart from the spirit and scope of the invention are covered by the scope of the claims of the present invention.

Claims

1. A method for collecting the temperature of a quantum cascade laser chip, characterized in that Including: Mount at least one temperature sensor on one side of the heat sink close to the laser emitting junction, collect real-time temperature values through the temperature sensor, preprocess multiple said temperature values, and calculate the real-time temperature of the laser based on multiple first temperature values obtained after the preprocessing by the moving average method.

2. The method according to claim 1, wherein Mount the temperature sensor on the side of the heat sink where the emitting junction and the heat sink solder joint are located.

3. The method according to claim 2, wherein Mount the temperature sensor at a position close to the emitting junction and close to the heat sink solder joint.

4. The method according to claim 3, characterized in that, Connect the temperature sensor and the heat sink through thermally conductive silver paste.

5. The method according to claim 4, characterized in that Connect the temperature sensor and the heat sink through the thermally conductive silver paste under hot pressing conditions.

6. The method according to claim 1, wherein The preprocessing includes: calculating the average value of the temperature values at multiple positions at the same moment as the first temperature value.

7. The method according to claim 6, wherein The preprocessing further includes: calculating the ratio of the temperature values at multiple moments at the same position to the corresponding time change amount to obtain a temperature change rate; calculating the standard deviation of the temperature change rates at multiple positions, and calculating the average value of the temperature values for which the standard deviation is less than or equal to a preset first threshold to obtain the first temperature value.

8. The method according to claim 7, wherein The preprocessing further includes: constructing a correction function based on the temperature values for which the standard deviation is less than or equal to a preset first threshold; using the correction function to correct the temperature values for which the standard deviation is greater than the first threshold.

9. The method according to claim 1, characterized in that The temperature sensor is set as a platinum resistance PT1000.

10. A quantum cascade laser chip temperature acquisition system, characterized in that, Including: One or more processors; A memory having stored thereon one or more programs which, when executed by the one or more processors, cause the one or more processors to implement the acquisition and preprocessing of temperature data in a method for acquiring the temperature of a quantum cascade laser chip according to any one of claims 1 to 9.

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