A laser power meter probe calibration system and method

Abstract

This invention discloses a laser power meter probe calibration system and method. The system includes a laser, a controller, a voltage acquisition unit, and a temperature sensor. The laser, controlled by the controller, emits laser light to the laser power meter probe under test at a calibrated power during several calibration cycles. The temperature sensor senses the temperature of the laser power meter probe under test. The voltage acquisition unit acquires the voltage signal from the laser power meter probe under test. The controller is configured to receive and record the temperature value acquired by the temperature sensor and the voltage signal value acquired by the voltage acquisition unit, and is configured to determine whether the laser power meter probe under test is in a first equilibrium state based on the temperature value and the voltage signal value, and whether it is in a second equilibrium state based on the voltage signal value. This invention improves the calibration efficiency of the laser power meter probe by introducing an auxiliary heat dissipation device, and simultaneously automates the laser power meter probe calibration process.

Description

Technical Field

[0001] This invention relates to the field of laser power meter technology, and in particular to a laser power meter probe calibration system and method. Background Technology

[0002] As an instrument probe specifically designed for measuring laser power, the air-cooled laser power meter probe uses air cooling to dissipate heat, ensuring stable and accurate measurements even in medium-power laser environments.

[0003] During the production process of air-cooled laser power meter probes, it is necessary to calibrate multiple power points within the probe's measurement range. The calibration of air-cooled laser power meter probes includes: 1) extracting the response curve of the thermopile voltage signal of the air-cooled laser power meter under standard laser source excitation; 2) establishing the mapping relationship between the thermopile voltage signal and the laser power value when the laser power meter reaches equilibrium under standard laser source excitation.

[0004] The calibration process for an air-cooled laser power meter probe requires recording the response curves of the thermopile at various power points, starting from a stable state at room temperature. Therefore, after recording the response curve for a particular power point, the laser must be turned off, and the entire power meter probe structure must cool down and reach thermal equilibrium with the external environment before recording the response curve for the next power point. This process of waiting for the power meter to reach thermal equilibrium takes a considerable amount of time, and during this period, the laser is idle, affecting the calibration efficiency of the power meter probe. Summary of the Invention

[0005] In a first aspect, the present invention provides a laser power meter probe calibration system, comprising:

[0006] Laser, controller, voltage acquisition unit, and temperature sensor;

[0007] The laser, under the control of the controller, is used to emit laser light to the probe of the laser power meter under test at a calibrated power during several calibration processes.

[0008] The temperature sensor is used to sense the temperature of the laser power meter probe under test;

[0009] The voltage acquisition device is used to acquire the voltage signal of the laser power meter probe under test;

[0010] The controller is configured to receive and record the temperature value collected by the temperature sensor and the voltage signal value collected by the voltage acquisition device, and is configured to determine whether the laser power meter probe under test is in a first equilibrium state based on the temperature value and the voltage signal value, and to determine whether the laser power meter probe under test is in a second equilibrium state based on the voltage signal value. The first equilibrium state is when the temperature of the laser power meter probe under test tends to be stable under the condition that the laser is turned off, and the second equilibrium state is when the voltage signal value output by the laser power meter probe under test tends to be stable under the condition that the laser emits laser at the calibrated power.

[0011] Secondly, the present invention provides a laser power meter probe calibration method, comprising:

[0012] Perform the calibration process several times according to a certain number of rated power values;

[0013] The calibration result is output by the controller of the laser power meter probe calibration system based on the calibration power used in each calibration process and the voltage signal value recorded by the calibration power condition in each calibration process. The calibration result includes several voltage signal values ​​collected based on the calibration power.

[0014] Each calibration process includes:

[0015] Place the laser power meter probe to be tested into the laser power meter probe calibration system;

[0016] The temperature sensor of the laser power meter probe calibration system senses the first temperature of the laser power meter probe under test under the test environment temperature conditions.

[0017] The voltage acquisition unit of the laser power meter probe calibration system acquires the first voltage signal of the laser power meter probe under test under the test environment temperature conditions.

[0018] With the laser in the laser power meter probe calibration system off, after the temperature of the laser power meter probe under test tends to stabilize, the controller controls the laser to turn on and emit laser light to the laser power meter probe under test at the calibration power for that test.

[0019] The voltage acquisition device acquires the second voltage signal of the laser power meter probe under the current calibration power condition;

[0020] After the second voltage signal value output by the probe of the laser power meter under test tends to stabilize, the controller controls the laser to turn off and records the voltage signal result value. Attached Figure Description

[0021] Figure 1This is a schematic diagram of the structure of a laser power meter probe calibration system according to the present invention;

[0022] Figure 2 This is another structural schematic diagram of a laser power meter probe calibration system according to the present invention;

[0023] Figure 3 This is a schematic flowchart of a laser power meter probe calibration method according to the present invention;

[0024] Figure 4 This is a flowchart illustrating each calibration process in the laser power meter probe calibration method of the present invention;

[0025] Figure label:

[0026] 2001, Laser emitter; 2002, Optical collimating lens; 2003, Optical fiber; 201, Controller; 202, Voltage acquisition unit; 203, Temperature sensor; 2041, Thermopile absorber; 2042, Heat sink; 2043, First fan; 2051, Transmission device; 2052, Auxiliary heat sink; 2053, Second fan. Detailed Implementation

[0027] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. These embodiments are illustrative of the invention but are not intended to limit its scope.

[0028] In the description of this invention, it should be understood that the terms "first" and "second," etc., are used to distinguish different objects, rather than to describe a specific order.

[0029] like Figure 1 As shown, the present invention provides a laser power meter probe calibration system, including: a laser, a controller 201, a voltage acquisition unit 202, and a temperature sensor 203.

[0030] The laser, controlled by the controller, is used to emit laser light to the probe of the laser power meter under test at a calibrated power during several calibration processes.

[0031] The laser power meter probe under test includes a thermopile absorber 2041, a heat sink 2042 connected to the thermopile absorber, and a first fan 2043 connected to the heat sink. The laser is configured to emit laser light towards the thermopile absorber and includes a laser emitter 2001, an optical collimating lens 2002, and an optical fiber 2003 connecting the laser emitter and the optical collimating lens. The optical collimating lens is configured such that its center is on the same straight line as the center of the thermopile absorber to ensure that the energy emitted by the laser emitter is well absorbed by the thermopile absorber during calibration.

[0032] The working principle of the laser power meter probe to be tested is explained below:

[0033] When a laser of a certain wavelength continuously irradiates the thermopile absorber, the absorber absorbs the laser energy at a certain absorptivity and converts it into heat energy. The heat energy is conducted to the surrounding air primarily through thermal convection via a heat sink. A first fan generates airflow by rotating, improving the heat dissipation efficiency of the heat sink through forced convection. Under relatively stable ambient temperature and laser output power, the entire laser power meter probe reaches an equilibrium state after a period of time. At this point, the temperature difference between the cold and hot ends of the thermopile surrounding the absorber tends to stabilize, which is represented at the signal level as a fixed voltage signal on the thermopile.

[0034] A temperature sensor is used to sense the temperature of the probe of the laser power meter under test. In some embodiments, the temperature sensor is used to sense the temperature of the heat sink, which serves as the basis for determining whether to start sampling the voltage signal of the thermopile after switching the calibration power point.

[0035] A voltage acquisition unit is used to acquire the voltage signal of the probe of the laser power meter under test. In some embodiments, the voltage acquisition unit is used to acquire the voltage signal of the thermopile absorber. The voltage acquisition unit is a high-precision voltage acquisition unit to achieve accurate acquisition of the voltage signal.

[0036] The controller is configured to receive and record temperature values ​​acquired by a temperature sensor and voltage signal values ​​acquired by a voltage acquisition unit. It is also configured to determine whether the laser power meter probe under test is in a first equilibrium state based on the temperature and voltage signal values, and whether it is in a second equilibrium state based on the voltage signal value. The first equilibrium state is when the temperature of the laser power meter probe under test tends to stabilize under laser off conditions. The second equilibrium state is when the voltage signal value output by the laser power meter probe under test tends to stabilize under laser emission at its rated power.

[0037] In some implementations, the controller is configured to output calibration results based on the calibration power during several calibration processes and the voltage signal values ​​acquired under the calibration power conditions of each calibration process. The calibration results include several voltage signal values ​​acquired based on the calibration power, and connecting these voltage signal values ​​in the calibration results yields a voltage signal response curve.

[0038] In some embodiments, the calibration result includes the average value of several voltage signal values ​​collected based on the calibration power within a first preset time range before the end of the current calibration process. This invention defines the above average value as the thermopile equilibrium voltage. In some embodiments, the first preset time range is 30 seconds, and the thermopile equilibrium voltage is the average value of several voltage signal values ​​collected based on the calibration power within 30 seconds before the end of the current calibration process. Simultaneously, a mapping relationship, i.e., a binary tuple, between the calibration power and the thermopile equilibrium voltage of the current calibration process is established and stored.

[0039] Figure 2 Schematic diagrams of some other embodiments of a laser power meter probe calibration system according to the present invention are shown. The laser power meter probe calibration system also includes an auxiliary heat dissipation device for cooling the laser power meter probe under test. The controller is configured to control the auxiliary heat dissipation device to cool the laser power meter probe under test, thereby accelerating the heat dissipation process and enabling the laser power meter probe under test to reach a first equilibrium state more quickly.

[0040] The auxiliary heat dissipation device includes a transmission device 2051, an auxiliary heat sink 2052 connected to the transmission device, and a second fan 2053 connected to the auxiliary heat sink. The controller is configured to control the transmission device to bring the auxiliary heat sink close to the laser power meter probe under test for heat dissipation. In other embodiments, the transmission device is a linear actuator. After calibration at a certain power point and the laser is turned off during the calibration process, the controller controls the linear actuator to bring the auxiliary heat sink into contact with the laser power meter probe under test, accelerating the process of the probe reaching a first equilibrium state. When the probe reaches the first equilibrium state, the controller controls the linear actuator to separate the auxiliary heat sink from the probe, ending the auxiliary heat dissipation process.

[0041] The present invention discloses a laser power meter probe calibration system, which reduces the time it takes for the laser power meter probe under test to recover to the first equilibrium state when there is no laser input by introducing an active auxiliary heat dissipation device, thereby improving the overall calibration efficiency of the laser power meter probe under test.

[0042] Based on the above-mentioned laser power meter probe calibration system, such as Figure 3 As shown, the present invention provides a laser power meter probe calibration method, including the following steps:

[0043] S1. Perform the calibration process several times according to a certain number of rated power values;

[0044] The calibration power is set based on the measurement range of the laser power meter probe under test. The measurement range of the laser power meter probe under test determines the maximum and minimum laser power it can measure. To ensure test accuracy, the calibration power should be selected within the measurement range of the laser power meter probe under test.

[0045] S2. Based on the calibration power used in each calibration process and the calibration power conditions of each calibration process, the controller of the laser power meter probe calibration system records the voltage signal value and outputs the calibration result.

[0046] The calibration results include several voltage signal values ​​acquired based on the calibration power. In some implementations, the voltage signal values ​​in the calibration results are connected to obtain a voltage signal response curve.

[0047] like Figure 4 As shown, each calibration process includes the following steps:

[0048] S11. Place the laser power meter probe to be tested into the laser power meter probe calibration system;

[0049] See Figure 1 The laser power meter probe to be tested is placed in the laser emission direction of the laser in the laser power meter probe calibration system so that the laser can emit laser to the laser power meter probe to be tested at the calibrated power during the calibration process.

[0050] S12, The temperature sensor of the laser power meter probe calibration system senses the first temperature of the laser power meter probe under test under the test environment temperature conditions;

[0051] S13. The voltage acquisition unit of the laser power meter probe calibration system acquires the first voltage signal of the laser power meter probe under test under the test environment temperature conditions.

[0052] S14. Under the condition that the laser is off in the laser power meter probe calibration system, after the temperature of the laser power meter probe to be tested tends to be stable, the controller controls the laser to be turned on and emits laser to the laser power meter probe to be tested at the calibration power of the current test.

[0053] With the laser off, based on the comparison of the first temperature and the temperature reference value, and the comparison of the first voltage signal and the voltage reference value, when the difference between the first temperature and the temperature reference value is within a first preset range and the difference between the first voltage signal and the voltage reference value is within a second preset range, the temperature of the laser power meter probe under test tends to stabilize. In other words, the laser power meter probe under test is in a first equilibrium state. It should be noted that the first temperature and the first voltage signal acquired during the first calibration process are not compared. Therefore, the first temperature during the first calibration process is used as the temperature reference value for subsequent calibration processes, and the first voltage signal during the first calibration process is used as the voltage reference value for subsequent calibration processes.

[0054] In some implementations, the first preset range is 0 to 0.5°C, and the second preset range is 0 to 0.02% of the voltage acquisition device's range. That is, when the difference between the first temperature and the temperature reference value is less than 0.5°C and the difference between the first voltage signal and the voltage reference value is less than 0.02% of the voltage acquisition device's range, the temperature of the laser power meter probe under test tends to be stable. At this time, the controller controls the laser to turn on and emits laser light to the laser power meter probe under test at the current calibrated power.

[0055] Based on the comparison between the first temperature and the temperature reference value, and the comparison between the first voltage signal and the voltage reference value, when the comparison result shows that the temperature of the laser power meter probe under test has not stabilized, the comparison between the first temperature and the temperature reference value and the comparison between the first voltage signal and the voltage reference value will be performed again after a third preset time range.

[0056] In some implementations, the third preset time range is 10 seconds. When the comparison result shows that the temperature of the laser power meter probe under test has not stabilized, the comparison based on the first temperature and the temperature reference value and the comparison based on the first voltage signal and the voltage reference value are performed again after 10 seconds, until the comparison result shows that the temperature of the laser power meter probe under test has stabilized.

[0057] S15. The voltage acquisition device acquires the second voltage signal of the laser power meter probe under the current calibration power condition.

[0058] It should be noted that the second voltage signal is the voltage signal of the laser power meter probe under test collected after the laser is turned on, while the first voltage signal is the voltage signal of the laser power meter probe under test collected when the laser is turned off.

[0059] S16. After the second voltage signal value output by the laser power meter probe under test tends to stabilize, the controller controls the laser to turn off and records the voltage signal result value.

[0060] Based on a comparison between the first average value of the second voltage signal acquired by the voltage acquisition device within a second preset time range and the second average value of the second voltage signal within the next second preset time range, when the rate of change between the second average value and the first average value is within a third preset range, the voltage value output by the laser power meter probe under test tends to stabilize. In other words, the laser power meter probe under test is in a second equilibrium state. At this time, the controller shuts off the laser and records the voltage signal result value.

[0061] In some implementations, the second preset time range is 30 seconds, and the third preset range is 0 to 0.05%. That is, based on the comparison between the first average value of the second voltage signal value collected by the voltage acquisition device within 30 seconds and the second average value of the second voltage signal value within the next 30 seconds, when the rate of change between the second average value and the first average value is less than 0.05%, the voltage value output by the probe of the laser power meter under test tends to be stable, that is, the rate of change of the 30-second average value of the second voltage signal sampling value is less than 0.05%, and the voltage value output by the probe of the laser power meter under test tends to be stable.

[0062] After the laser is turned on for a fourth preset time range, the first average value of the second voltage signal collected by the voltage collector in the second preset time range is compared with the second average value of the second voltage signal in the next second preset time range. When the comparison result is that the voltage value output by the probe of the laser power meter under test has not stabilized, the comparison is performed again after a fifth preset time range, based on the first average value of the second voltage signal collected by the voltage collector in the second preset time range and the second average value of the second voltage signal in the next second preset time range.

[0063] In some implementations, the fourth preset time range is 6 minutes, and the fifth preset time range is 10 seconds. After the laser is turned on for 6 minutes, the first average value of the second voltage signal value collected by the voltage collector within 30 seconds is compared with the second average value of the second voltage signal value within the next 30 seconds. When the comparison result is that the voltage value output by the probe of the laser power meter under test has not stabilized, the comparison is repeated after 10 seconds, based on the first average value of the second voltage signal value collected by the voltage collector within 30 seconds and the second average value of the second voltage signal value within the next 30 seconds, until the comparison result is that the voltage value output by the probe of the laser power meter under test has stabilized.

[0064] The voltage signal result value is the average of several voltage signal values ​​collected based on the calibration power within a first preset time range before the end of the current calibration process. This invention defines the aforementioned voltage signal result value as the thermopile equilibrium voltage. In some embodiments, the first preset time range is 30 seconds, and the thermopile equilibrium voltage is the average of several voltage signal values ​​collected based on the calibration power within 30 seconds before the end of the current calibration process. Simultaneously, a mapping relationship, i.e., a binary tuple, between the calibration power and the thermopile equilibrium voltage of the current calibration process is established and stored.

[0065] This invention provides a laser power meter probe calibration method. By real-time acquisition of voltage signals and temperature in the laser power meter probe under test, it provides the basis for judging whether the laser power meter probe under test has reached the first equilibrium state and the second equilibrium state, respectively, thereby automating the calibration process.

[0066] In summary, the laser power meter probe calibration system and method of the present invention improves the overall calibration efficiency of the laser power meter probe by introducing an active auxiliary heat dissipation device to reduce the time it takes for the probe to recover to the first equilibrium state when there is no laser input. Furthermore, by real-time acquisition of voltage signals and temperature in the laser power meter probe, the system provides criteria for determining whether the probe has reached the first and second equilibrium states, respectively, thus automating the calibration process.

[0067] The various embodiments in this specification are described in a progressive manner. For directly identical or similar parts of each embodiment, refer to the other embodiments. Each embodiment focuses on its differences from other embodiments. It should be noted that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as these combinations of technical features do not contradict each other, they should be considered within the scope of this specification.

[0068] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A laser power meter probe calibration system, characterized in that, include: Laser, controller, voltage acquisition unit, and temperature sensor; The laser, under the control of the controller, is used to emit laser light to the probe of the laser power meter under test at a calibrated power during several calibration processes. The temperature sensor is used to sense the temperature of the laser power meter probe under test; The voltage acquisition device is used to acquire the voltage signal of the laser power meter probe under test; The controller is configured to receive and record the temperature value collected by the temperature sensor and the voltage signal value collected by the voltage acquisition device, and is configured to determine whether the laser power meter probe under test is in a first equilibrium state based on the temperature value and the voltage signal value, and to determine whether the laser power meter probe under test is in a second equilibrium state based on the voltage signal value. The first equilibrium state is when the temperature of the laser power meter probe under test tends to be stable under the condition that the laser is turned off, and the second equilibrium state is when the voltage signal value output by the laser power meter probe under test tends to be stable under the condition that the laser emits laser at the calibrated power.

2. The laser power meter probe calibration system according to claim 1, characterized in that, The laser power meter probe under test includes a thermopile absorber, a heat sink connected to the thermopile absorber, and a first fan connected to the heat sink, wherein the laser is configured to emit a laser toward the thermopile absorber.

3. The laser power meter probe calibration system according to claim 2, characterized in that, The laser includes a laser emitter, an optical collimating lens, and an optical fiber connecting the laser emitter and the optical collimating lens. The optical collimating lens is configured such that the center of the optical collimating lens is on the same straight line as the center of the thermopile absorber.

4. The laser power meter probe calibration system according to claim 2, characterized in that, The temperature sensor is used to sense the temperature of the heat sink.

5. The laser power meter probe calibration system according to claim 2, characterized in that, The voltage acquisition device is used to acquire the voltage signal of the thermopile absorber.

6. The laser power meter probe calibration system according to claim 2, characterized in that, The controller is configured to output a calibration result based on the calibration power during several calibration processes and the voltage signal values ​​acquired under the calibration power conditions of each calibration process. The calibration result includes several voltage signal values ​​acquired based on the calibration power.

7. The laser power meter probe calibration system according to claim 1, characterized in that, The laser power meter probe calibration system further includes an auxiliary heat dissipation device for dissipating heat from the laser power meter probe under test, and the controller is configured to control the auxiliary heat dissipation device to dissipate heat from the laser power meter probe under test.

8. The laser power meter probe calibration system according to claim 7, characterized in that, The auxiliary heat dissipation device includes a transmission device, an auxiliary heat sink connected to the transmission device, and a second fan connected to the auxiliary heat sink. The controller is configured to control the transmission device to bring the auxiliary heat sink close to the laser power meter probe under test to dissipate heat from the laser power meter probe under test.

9. The laser power meter probe calibration system according to claim 6, characterized in that, The calibration result includes the average value of several voltage signal values ​​collected based on the calibration power within a first preset time range before the end of the current calibration process.

10. A method for calibrating a laser power meter probe, characterized in that, include: Perform the calibration process several times according to a certain number of rated power values; The calibration result is output by the controller of the laser power meter probe calibration system based on the calibration power used in each calibration process and the voltage signal value recorded by the calibration power condition in each calibration process. The calibration result includes several voltage signal values ​​collected based on the calibration power. Each calibration process includes: Place the laser power meter probe to be tested into the laser power meter probe calibration system; The temperature sensor of the laser power meter probe calibration system senses the first temperature of the laser power meter probe under test under the test environment temperature conditions. The voltage acquisition unit of the laser power meter probe calibration system acquires the first voltage signal of the laser power meter probe under test under the test environment temperature conditions. With the laser in the laser power meter probe calibration system off, after the temperature of the laser power meter probe under test tends to stabilize, the controller controls the laser to turn on and emit laser light to the laser power meter probe under test at the calibration power for that test. The voltage acquisition device acquires the second voltage signal of the laser power meter probe under the current calibration power condition; After the second voltage signal value output by the probe of the laser power meter under test tends to stabilize, the controller controls the laser to turn off and records the voltage signal result value.

11. The laser power meter probe calibration method according to claim 10, characterized in that, Under the condition that the laser is off, based on the comparison between the first temperature and the temperature reference value and the comparison between the first voltage signal and the voltage reference value, when the difference between the first temperature and the temperature reference value is within a first preset range and the difference between the first voltage signal and the voltage reference value is within a second preset range, the temperature of the probe of the laser power meter under test tends to be stable. In this case, the first temperature in the first calibration process is used as the temperature reference value in the subsequent calibration process, and the first voltage signal in the first calibration process is used as the voltage reference value in the subsequent calibration process.

12. The laser power meter probe calibration method according to claim 10, characterized in that, During each calibration process, the first average value of the second voltage signal collected by the voltage acquisition device within the second preset time range is compared with the second average value of the second voltage signal within the next second preset time range. When the rate of change between the second average value and the first average value is within the third preset range, the second voltage signal value output by the laser power meter probe under test tends to be stable.

13. The laser power meter probe calibration method according to claim 11, characterized in that, Based on the comparison between the first temperature and the temperature reference value and the comparison between the first voltage signal and the voltage reference value, when the comparison result is that the temperature of the laser power meter probe under test has not reached a stable state, the comparison between the first temperature and the temperature reference value and the comparison between the first voltage signal and the voltage reference value will be performed again after a third preset time range.

14. The laser power meter probe calibration method according to claim 12, after the laser is turned on for a fourth preset time range, a comparison is made between the first average value of the second voltage signal value collected by the voltage collector within a second preset time range and the second average value of the second voltage signal value within the next second preset time range. When the comparison result is that the voltage value output by the laser power meter probe under test has not stabilized, a comparison is made again after a fifth preset time range between the first average value of the second voltage signal value collected by the voltage collector within a second preset time range and the second average value of the second voltage signal value within the next second preset time range.

15. The laser power meter probe calibration method according to claim 10, characterized in that, The voltage signal result value is based on the average value of several voltage signal values ​​collected based on the calibration power within a first preset time range before the end of the current calibration process.

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