Method for measuring temperature of laser core, measuring system and laser detection device

Abstract

The application provides a laser core temperature measurement method, a measurement system and a laser detection device. The measurement method comprises the following steps: step A, obtaining a wavelength change curve of a laser and a core temperature of the laser by controlling the laser to work at different powers respectively; step B, obtaining an output wavelength of the laser; and step C, obtaining the core temperature of the laser based on the output wavelength of the laser and the wavelength change curve of the laser and the core temperature of the laser. The above scheme facilitates measurement of the laser core temperature.

Description

Technical Field

[0001] This specification relates to the field of laser measurement technology, and in particular to a method, system and device for measuring the core temperature of a laser. Background Technology

[0002] Semiconductor lasers are widely used in current lidar systems, offering advantages such as small size, long lifespan, high stability, high energy efficiency, and low cost. The core temperature of a semiconductor laser directly affects its performance and lifespan; therefore, studying the core temperature characteristics is a crucial technique for analyzing laser performance. Furthermore, accurately obtaining the core temperature of semiconductor lasers is essential for lidar design, especially for automotive-grade applications. For example, it's important to determine whether the design of the lidar's heat dissipation and laser arrangement might lead to excessively high core temperatures and laser failure.

[0003] For temperature measurement, there are direct contact measurement and non-contact indirect measurement methods.

[0004] However, due to the small size of the lasers used in current lidar systems, traditional direct-contact measurement methods are difficult to implement. For example, thermocouples are not easily attached to the laser, and the laser is fragile; removing the thermocouple after measurement can easily damage it. Furthermore, the laser is sensitive to heat capacity, and even with a thermocouple attached, its operating state will differ from its unattached state.

[0005] Given the numerous problems associated with contact-based measurements mentioned above, current technologies primarily utilize thermal imagers to measure the core temperature of lasers in a non-contact manner. While this indirect, non-contact measurement method does not affect the normal operation of the laser, it becomes inconvenient to measure after the laser is integrated into a radar system. Existing technologies also involve comparing images of the laser with and without current to ultimately obtain the core temperature; however, this method requires a microscope, is complex, and lacks real-time accuracy. Summary of the Invention

[0006] In view of this, embodiments of this specification provide a non-contact method, measurement system, and laser detection device for measuring the core temperature of a laser, which facilitates the measurement of the core temperature of a laser.

[0007] First, this specification provides an embodiment of a method for measuring the core temperature of a laser, the method comprising:

[0008] Step A: By controlling the laser to operate at different powers, obtain the curves showing the change between the wavelength of the laser and the core temperature of the laser.

[0009] Step B: Obtain the output wavelength of the laser;

[0010] Step C: Based on the output wavelength of the laser, the core temperature of the laser is obtained according to the curve of the change between the laser wavelength and the core temperature of the laser.

[0011] Optionally, step A includes:

[0012] Step A1: Control the laser to operate at a first power and a second power respectively, and obtain a first change curve and a second change curve. The first change curve is the curve of the output wavelength of the laser at the first power changing with the temperature measured by the temperature measuring unit, and the second change curve is the curve of the output wavelength of the laser at the second power changing with the temperature measured by the temperature measuring unit. The temperature measuring unit and the laser are located at different positions, and the laser and the temperature measuring unit form a thermal resistance network.

[0013] Step A2: Based on the first change curve and the second change curve, obtain the change curve of the laser wavelength versus the core temperature of the laser.

[0014] Optionally, step A1 includes:

[0015] Step A11: Control the laser to operate at a first power, obtain the output wavelength of the laser, and obtain the temperature value of the temperature measurement unit to obtain a first change curve of the output wavelength of the laser as a function of the temperature value of the temperature measurement unit.

[0016] Step A12: Control the laser to operate at the second power, obtain the output wavelength of the laser, and obtain the temperature value of the temperature measurement unit to obtain a second curve showing the change of the output wavelength of the laser with the temperature value of the temperature measurement unit.

[0017] Optionally, the laser is disposed in a laser detection device, and step A11 includes:

[0018] The laser is controlled to start working at a first power, and a first change curve of the output wavelength of the laser as a function of the temperature value of the temperature measurement unit is obtained from the time the laser is turned on until the laser detection device reaches a stable temperature.

[0019] Step A12 includes:

[0020] The laser is controlled to start working at a second power, and a second variation curve of the output wavelength of the laser as a function of the temperature value of the temperature measurement unit is obtained from the time the laser is turned on until the laser detection device reaches a stable temperature.

[0021] Optionally, step A2 includes:

[0022] Step A21: Obtain the distance between the first change curve and the second change curve along the temperature axis to obtain the first temperature difference;

[0023] Step A22: Shift the first variation curve along the temperature axis by a preset distance to obtain the variation curve of the laser's wavelength and the laser's core temperature, wherein the second temperature difference corresponding to the preset distance satisfies the following relationship with the first temperature difference:

[0024] ΔT1′=1 / (x-1)ΔT′;

[0025] Wherein, ΔT1′ represents the second temperature difference, ΔT′ represents the first temperature difference, x represents the ratio of the second power to the first power, and x>1.

[0026] Optionally, x is 2.

[0027] Optionally, the laser is disposed in a laser detection device, and step B includes:

[0028] The laser detection device is controlled to operate in normal mode to obtain the output wavelength of the laser.

[0029] This specification also provides an embodiment of a laser core temperature measurement system, wherein the laser is disposed in a laser detection device, and the measurement system includes:

[0030] A storage unit is adapted to store the change curve of the laser wavelength versus the laser core temperature, wherein the change curve of the laser wavelength versus the laser core temperature is obtained by controlling the laser to operate at different power levels;

[0031] A wavelength detection unit, adapted to detect the output wavelength of the laser;

[0032] The processing unit is adapted to obtain the core temperature of the laser based on the output wavelength of the laser and according to the curve of the change between the wavelength of the laser and the core temperature of the laser.

[0033] Optionally, the measurement system further includes:

[0034] A control unit is adapted to control the laser to operate at a first power and a second power, respectively;

[0035] A temperature measurement unit is located at a different position from the laser and forms a thermal resistance network with the laser. It is adapted to detect the temperature at the corresponding temperature measurement position when the laser is operating at the first power and the second power, and output the temperature to the processing unit.

[0036] The wavelength detection unit is also adapted to detect the output wavelength of the laser when the laser is operating at the first power and the second power, respectively;

[0037] The processing unit is adapted to obtain a first change curve and a second change curve based on the detection results of the temperature measurement unit and the wavelength detection unit when the laser operates at a first power and a second power, and to obtain and store the change curve of the laser wavelength versus the core temperature of the laser in the storage unit according to the first change curve and the second change curve; wherein, the first change curve is the change curve of the laser output wavelength at the first power versus the temperature measured by the temperature measurement unit, and the second change curve is the change curve of the laser output wavelength at the second power versus the temperature measured by the temperature measurement unit.

[0038] Optionally, the temperature measuring unit includes at least one of the following types:

[0039] Thermistors with negative temperature coefficients;

[0040] Thermocouple.

[0041] Optionally, the processing unit is adapted to obtain the distance between the first change curve and the second change curve along the temperature axis to obtain a first temperature difference; and to shift the first change curve along the temperature axis by a preset distance to obtain the change curve of the laser wavelength and the laser core temperature, wherein the second temperature difference corresponding to the preset distance satisfies the following relationship with the first temperature difference:

[0042] ΔT1′=1 / (x-1)ΔT′;

[0043] Wherein, ΔT1′ represents the second temperature difference, ΔT′ represents the first temperature difference, x represents the ratio of the second power to the first power, and x>1.

[0044] Optionally, the measurement system further includes a diffuse reflection unit, wherein the laser emitted by the laser is reflected by the diffuse reflection unit and then detected by the wavelength detection unit.

[0045] Optionally, the wavelength detection unit is adapted to acquire the output wavelength of the laser when the laser detection device is in normal operating mode.

[0046] This specification also provides a laser detection device, including: a transmitter and a controller, wherein:

[0047] The transmitting device includes a laser;

[0048] The controller, coupled to the transmitting device, is adapted to control the laser to operate at different powers according to preset transmission control parameters, so as to obtain the wavelength-to-core temperature variation curve of the laser; and to obtain the core temperature of the laser based on the obtained output wavelength and the wavelength-to-core temperature variation curve.

[0049] Optionally, the transmitting device further includes:

[0050] A printed circuit board, wherein the laser is disposed on the printed circuit board;

[0051] A temperature measurement unit is located on the printed circuit board at a different position from the laser, forming a thermal resistance network with the laser, and is suitable for measuring the temperature at its location.

[0052] Optionally, the printed circuit board is provided with multiple lasers, and the temperature measurement unit includes multiple temperature sensors corresponding to the multiple lasers respectively.

[0053] The laser core temperature measurement method described in this specification utilizes the laser's temperature drift characteristics to measure its core temperature; that is, the laser's wavelength drifts with changes in its core temperature. Specifically, by controlling the laser to operate at different power levels, the change curve of the laser's wavelength versus its core temperature can be obtained, and the laser's output wavelength can be acquired. Based on the output wavelength and the change curve of the laser's wavelength versus its core temperature, the laser's core temperature is obtained. As can be seen from the above measurement process, only one calibration is needed to obtain the relationship between the laser's wavelength and its core temperature, and the laser's output wavelength can be obtained without physical contact. Therefore, the laser's core temperature can be obtained based on the change curve of its wavelength versus its core temperature. Thus, the actual measurement process does not affect the normal operation of the laser, allowing for convenient and accurate acquisition of the laser's core temperature during normal operation.

[0054] Furthermore, the laser is controlled to operate at a first power and a second power respectively, and a first change curve and a second change curve are obtained. Then, based on the first change curve and the second change curve, the change curve of the laser wavelength versus the laser core temperature is obtained. The first change curve is the change curve of the laser output wavelength at the first power versus the temperature measured by the temperature measuring unit, and the second change curve is the change curve of the laser output wavelength at the second power versus the temperature measured by the temperature measuring unit. The temperature measuring unit is located at a different position from the laser, and the laser and the temperature measuring unit form a thermal resistance network. Therefore, by controlling the laser to operate at two power levels and obtaining the temperature readout from the temperature measuring unit located at a different position from the laser, the drift curve of the laser wavelength versus its core temperature can be obtained. This dual-power measurement process is simple, requires no disassembly, does not affect the normal operation of the laser, and can more accurately reflect the core temperature of the laser during normal operation.

[0055] Furthermore, the laser is installed in the laser detection device. First, the laser is controlled to start working at a first power to obtain a first curve showing the change of the laser's output wavelength with the temperature value of the temperature measurement unit from the time the laser is turned on until the laser detection device reaches a stable temperature. Then, the laser is controlled to start working at a second power to obtain a second curve showing the change of the laser's output wavelength with the temperature value of the temperature measurement unit from the time the laser is turned on until the laser detection device reaches a stable temperature. In this measurement process, by starting the laser twice with different powers, the influence of the first measurement process on the temperature change in the second measurement process can be reduced, thereby further improving the accuracy of this non-contact measurement method.

[0056] Furthermore, by obtaining the distance between the first and second variation curves along the temperature axis, a first temperature difference is obtained. Then, the first variation curve is shifted along the temperature axis by a preset distance to obtain the variation curve of the laser wavelength versus the laser core temperature. The second temperature difference corresponding to the preset distance satisfies the following relationship with the first temperature difference: ΔT1′=1 / (x-1)ΔT′; where ΔT1′ represents the second temperature difference, ΔT′ represents the first temperature difference, and x represents the ratio of the second power to the first power. Therefore, after obtaining the first and second variation curves by measurement, based on the temperature drift characteristics of the laser, no complex calculation process is required. The variation curve of the laser wavelength versus the laser core temperature can be obtained through a simple translation transformation, which is simple and easy to implement.

[0057] Furthermore, by controlling the laser detection device to operate in normal mode and obtaining the output wavelength of the laser, the core temperature of the laser obtained is the core temperature of the laser detection device in normal operating mode, thus making the measurement more accurate. Attached Figure Description

[0058] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0059] Figure 1 A flowchart illustrating a method for measuring the core temperature of a laser according to an embodiment of this specification is shown;

[0060] Figure 2 A schematic diagram showing the relationship between the wavelength of a laser and the core temperature of the laser is provided.

[0061] Figure 3 A flowchart illustrating an embodiment of this specification for obtaining the relationship between the wavelength of the laser and the core temperature of the laser is shown.

[0062] Figure 4 A schematic diagram of the thermal resistance network formed by the laser and the temperature measurement unit in an embodiment of this specification is shown.

[0063] Figure 5 A flowchart illustrating one method for obtaining a first change curve and a second change curve in an embodiment of this specification is shown.

[0064] Figure 6 A flowchart showing the variation curve of the wavelength of a laser generator with the core temperature of the laser in an embodiment of this specification is illustrated.

[0065] Figure 7 This specification illustrates a process for obtaining a curve showing the change between the wavelength of a laser and the core temperature of the laser in an embodiment of this specification.

[0066] Figure 8 A schematic diagram showing a curve of the change between the wavelength of a laser and the core temperature of the laser is provided.

[0067] Figure 9 A schematic diagram of a laser core temperature measurement system according to an embodiment of this specification is shown;

[0068] Figure 10A schematic diagram of a laser core temperature measurement system according to an embodiment of this specification is shown.

[0069] Figure 11 A schematic diagram of a measurement system for another laser core temperature measurement system is shown in an embodiment of this specification;

[0070] Figure 12 A schematic diagram of the structure of a laser detection device in one of the embodiments of this specification is shown. Detailed Implementation

[0071] As mentioned earlier, after lasers are integrated into laser detection systems, existing laser measurement methods present many inconveniences.

[0072] To facilitate the measurement of laser core temperature, this specification provides a non-contact method and system for measuring laser core temperature. By utilizing the temperature drift characteristics of the laser to measure the laser core temperature, more accurate measurement of the laser core temperature can be achieved during laser operation.

[0073] To enable those skilled in the art to better understand the concept, advantages, and implementation schemes of the solutions provided in this specification, the following detailed description and examples of the principles of the laser core temperature measurement method and system, laser detection equipment, and other schemes provided in the embodiments of this specification are given with reference to the accompanying drawings and through specific examples.

[0074] Reference Figure 1 The flowchart shown illustrates a method for measuring the laser core temperature. In this embodiment of the specification, the laser core temperature can be measured using the following steps:

[0075] Step A: By controlling the laser to operate at different powers, obtain the curves showing the change between the wavelength of the laser and the core temperature of the laser.

[0076] Lasers exhibit temperature drift characteristics, meaning their wavelength shifts with changes in their core temperature. Figure 2 The diagram illustrates the relationship between the wavelength of a laser and its core temperature. When the core temperature is T1, the corresponding laser wavelength is λ1; when the core temperature rises to T2, the laser wavelength is λ2. Therefore, the relationship between the laser wavelength and its core temperature can be calculated by measurement, and subsequently, the core temperature of the laser can be obtained from the laser's output wavelength.

[0077] Currently, existing lasers only have a single value for their core parameters: the slope. This means that only the relationship between temperature change ΔT and wavelength change Δλ can be obtained, not the precise relationship between the laser's core temperature and wavelength. Therefore, even if the laser's output wavelength is obtained, its core temperature cannot be determined. To address this, this embodiment controls the laser to operate at different powers, enabling the acquisition of curves showing the change in wavelength versus core temperature.

[0078] Step B: Obtain the output wavelength of the laser.

[0079] In practice, the output wavelength of the laser can be obtained using a wavelength detection device, such as a spectrometer. No contact with the laser is required during the measurement process.

[0080] As an optional example, when the laser is set in the laser detection device, the laser detection device can be controlled to operate in the normal working mode to obtain the output wavelength of the laser.

[0081] By controlling the laser detection device to operate in normal mode, the output wavelength of the laser is obtained, and the core temperature of the laser is the core temperature of the laser detection device in normal operating mode. Therefore, the measurement is more accurate and can provide important basis for the design and performance monitoring of the laser detection device.

[0082] Step C: Based on the output wavelength of the laser, the core temperature of the laser is obtained according to the curve of the change between the laser wavelength and the core temperature of the laser.

[0083] Using the above embodiments, the relationship between the wavelength of the laser and the core temperature of the laser can be obtained in advance. Therefore, without the need for contact measurement to obtain the output wavelength of the laser, the core temperature of the laser can be obtained based on the pre-obtained curve of the change between the wavelength and the core temperature of the laser. Thus, the actual measurement process will not affect the normal operation of the laser, and there is no need to disassemble the laser detection equipment containing the laser. The core temperature of the laser during normal operation can be obtained conveniently and accurately.

[0084] To enable those skilled in the art to better understand and implement this method, the following specific example illustrates how to obtain the relationship between the wavelength of the laser and the core temperature of the laser. (Refer to...) Figure 3 Specifically, it can be done through the following steps:

[0085] Step A1: Control the laser to operate at a first power and a second power respectively, and obtain a first change curve and a second change curve.

[0086] The first variation curve represents the change in the output wavelength of the laser at a first power as a function of the temperature measured by the temperature measuring unit; the second variation curve represents the change in the output wavelength of the laser at a second power as a function of the temperature measured by the temperature measuring unit. The temperature measuring unit and the laser are located at different positions, and the laser and the temperature measuring unit form a thermal resistance network.

[0087] Heat flow, also known as thermal power, is the amount of heat transferred through an object of a certain area per unit time by conduction, convection, or radiation when there is a temperature difference between its two sides. The heat flow through an object is directly proportional to the temperature difference between its two sides, inversely proportional to its thickness, and related to the thermal conductivity of the material. Thermal resistance refers to the resistance encountered by heat along its path, reflecting the heat transfer capacity of a medium or between media. It indicates the temperature rise caused by 1W of heat, and is measured in °C / W or K / W.

[0088] like Figure 4 As shown, the laser LD and the temperature measurement unit TMU are located at different positions, forming a thermal resistance network TR0. For the same thermal resistance network, the thermal resistance distribution remains constant. Let the temperature of the laser LD be T. LD The temperature of the temperature measurement unit (TMU) is T. TMU Then the temperature difference ΔT between the laser LD and the temperature measurement unit TMU is T LD -T TMU Temperature is in °C or K, thermal resistance is R, and the unit is °C / W or K / W.

[0089] According to Q = ΔT / R, where Q is the heat flow between the laser and the temperature measuring unit in W, the curve of the output wavelength of the laser changing with the temperature measured by the temperature measuring unit under different thermal powers can be measured.

[0090] It should be noted that the aforementioned first power and second power can be considered the thermal power of the laser, which differs from the electrical power supplied to the laser by the power source. Electrical power can be converted into optical power and thermal power. Optical power is used to provide the emitted light, and thermal power is used to generate heat flow between the laser and the temperature measurement unit. The electro-optical conversion efficiency is a fixed value for the same laser; therefore, the thermal power and the electrical power supplied to the laser are in a fixed ratio. Thus, regardless of whether the judgment is based on electrical power or thermal power, by controlling the laser to operate at different power levels, the change curve of the laser's wavelength versus its core temperature can be obtained. In specific implementations, the overall power of the equipment containing the laser during its operation can also be used as a standard. Measurements can be performed by changing the power of the equipment, as long as the actual power of the laser differs in two or more measurements.

[0091] Step A2: Based on the first change curve and the second change curve, obtain the change curve of the laser wavelength versus the core temperature of the laser.

[0092] In the above embodiments, by controlling the laser to operate at two different power levels and by reading the temperature from a temperature measurement unit located at a different position from the laser, the drift curve of the laser's wavelength as a function of its core temperature can be obtained. This dual-power measurement process is simple, requires no disassembly, does not affect the normal operation of the laser, and can more accurately reflect the core temperature of the laser when it is operating normally.

[0093] The following uses a specific application scenario as an example. Figures 5 to 7 This describes a specific method for obtaining the curves showing the change between the wavelength of a laser and the core temperature of the laser through a dual-power measurement process.

[0094] In some embodiments of this specification, step A1 may specifically include steps A11 and A12, as described above. Figure 5 The flowchart shown illustrates the acquisition of the first and second change curves, where:

[0095] Step A11: Control the laser to operate at a first power, obtain the output wavelength of the laser, and obtain the temperature value of the temperature measurement unit to obtain a first change curve of the output wavelength of the laser as a function of the temperature value of the temperature measurement unit.

[0096] Step A12: Control the laser to operate at the second power, obtain the output wavelength of the laser, and obtain the temperature value of the temperature measurement unit to obtain a second curve showing the change of the output wavelength of the laser with the temperature value of the temperature measurement unit.

[0097] As an alternative example, the laser can be installed in a laser detection device, such as a lidar unit. The laser can be initially controlled to start operating at a first power level, and a first curve showing the change in the laser's output wavelength as a function of the temperature measurement unit can be obtained from the time the laser is turned on until the laser detection device reaches a stable temperature. For example, during this process, at different time points such as t... 1 Record wavelength λ at time 1 1 1. Temperature T TMU 1 1, at t 1 Record wavelength λ at time 2 1 2. Temperature T TMU 1 2, at t 1 Record wavelength λ at 3 o'clock 13. Temperature T TMU 1 3, ... in t 1 Record wavelength λ at time n 1 n, temperature T TMU 1 n, thus forming multiple sets of data on the laser output wavelength and the temperature value of the temperature measurement unit ([λ 1 1,T TMU 1 1],[λ 1 2,T TMU 1 2],[λ 1 3,T TMU 1 3]…[λ 1 n,T TMU 1 After fitting the data, the first variation curve described above can be obtained. Then, the laser is controlled to start operating at a second power to obtain a second variation curve showing the change in the laser's output wavelength with the temperature value of the temperature measurement unit from the time the laser is turned on until the laser detection device reaches a stable temperature. Multiple sets of data on the laser output wavelength and the temperature value of the temperature measurement unit ([λ]) are then used. 2 1,T TMU 2 1],[λ 2 2,T TMU 2 2],[λ 2 3,T TMU 2 3]…[λ 2 n,T TMU 2 The acquisition process for [n] is similar to that described above; after fitting, the second change curve can be obtained. In a specific implementation, after obtaining the first change curve, the laser detection device can be turned off, and then turned back on at the second power to obtain the second change curve.

[0098] In specific implementation, the working power of the laser can be set when the laser detection device is started, or the overall working power of the laser detection device can be set to obtain the curve of the change of the output wavelength of the laser at the corresponding power as a function of the temperature value of the corresponding temperature measurement unit.

[0099] For example, firstly, the laser detection equipment is started. At this time, the laser starts working at the first power P1. From the start-up until the entire system of the laser detection equipment reaches a stable temperature, the temperature of the entire system and the temperature measurement unit (TMU) gradually rise, and the following data can be obtained: Figure 7The first curve T shown in a) illustrates the variation of the output wavelength λ of the laser with the temperature value of the temperature measurement unit TMU. TMU (λ, P1). At this point, refer to... Figure 4 If the temperature difference between the laser and the temperature measuring unit is ΔT1=P1*R, then:

[0100] T LD (λ)=T TMU (λ,P1)+P1*R (1)

[0101] Right now:

[0102] T LD (λ)-T TMU (λ, P1) = P1 * R (2)

[0103] Afterwards, the laser detection device is powered off. Once it has completely cooled down, it is restarted. At this point, the laser starts operating at the second power P2. A second curve T, showing the change in the laser's output wavelength λ as a function of the temperature value of the temperature measurement unit TMU, can be obtained from the time the laser is turned on until the laser detection device reaches a stable temperature. TMU (λ, P2), such as Figure 7 As shown in b). At this point, continue referring to... Figure 4 If the temperature difference between the laser and the temperature measuring unit is ΔT2=P2*R, then:

[0104] T LD (λ)=T TMU (λ,P2)+P2*R (3)

[0105] Right now:

[0106] T LD (λ)-T TMU (λ, P2) = P2 * R (4)

[0107] Since the temperature drift coefficient of a laser is a relatively stable value, meaning the core temperature increases linearly with wavelength (over a wide temperature range), theoretically, two parallel straight lines can be obtained, namely the first variation curve T. TMU (λ, P1) and the second variation curve T TMU (λ, P2) are parallel lines.

[0108] After obtaining the first change curve T TMU (λ, P1) and the second variation curve T TMU After (λ, P2), refer to Figure 6 and Figure 7Following steps c) and d), steps A21 and A22 can be performed. The following will continue to explain in detail how to obtain the wavelength of the laser and the core temperature of the laser based on the first change curve and the second change curve.

[0109] In some embodiments of this specification, reference is made to Figure 6 Step A2 may specifically include the following steps:

[0110] Step A21: Obtain the distance between the first change curve and the second change curve in the temperature axis direction to obtain the first temperature difference.

[0111] Step A22: Shift the first variation curve along the temperature axis by a preset distance to obtain the variation curve of the laser wavelength and the core temperature of the laser.

[0112] The second temperature difference corresponding to the preset distance satisfies the following relationship with the first temperature difference:

[0113] ΔT1′=1 / (x-1)ΔT′;

[0114] Wherein, ΔT1′ represents the second temperature difference, ΔT′ represents the first temperature difference, and x represents the ratio of the second power to the first power.

[0115] In specific implementation, as mentioned above, due to the first change curve T TMU (λ, P1) and the second variation curve T TMU (λ, P2) are parallel to each other, therefore, the first temperature difference ΔT′ can be obtained through step A21, as follows. Figure 7 As shown in c). Afterwards, step A22 can be performed to change the first change curve T. TMU By shifting (λ, P1) upwards by a preset distance ΔT1′, the curve T showing the change in wavelength versus core temperature of the laser can be obtained. LD (λ). Where ΔT1′=1 / (x-1)ΔT′, x represents the ratio of the second power to the first power, and x>1. The ratio can be an integer multiple or a non-integer multiple.

[0116] Refer to each Figure 7 d) and Figure 8 ,in, Figure 7 In (d), x = 2, meaning the second power is twice the first power, i.e., P2 = 2 * P1. Therefore:

[0117] T TMU (λ, P2) = T LD (λ)-2P1*R (5)

[0118] Right now:

[0119] T LD (λ)-T TMU (λ, P2) = 2P1*R (6)

[0120] At this time, ΔT1′=ΔT′, and combining equations (2) and (6), it can be seen that the wavelength of the laser is related to the change curve of the core temperature of the laser. LD (λ) and the second variation curve T TMU The temperature difference ΔT2′ between (λ, P2) is the change curve T. LD (λ) and the first change curve T TMU The temperature difference ΔT1′ between (λ, P1) is twice the value of the first variation curve T. TMU (λ, P1) and the second variation curve T TMU The temperature difference ΔT′ between (λ, P2) is then used to plot the first variation curve T. TMU By shifting (λ, P1) upwards by ΔT′, we can obtain the curve T showing the relationship between the wavelength of the laser and the core temperature of the laser. LD (λ). When x = 2, T is obtained. LD (λ) is the simplest.

[0121] For example Figure 8 In this case, x = 2.6, meaning the second power is 2.6 times the first power, i.e., P2 = 2.6 * P1. At this time, ΔT1′ = 0.625ΔT′, which means that when the first change curve T is obtained... TMU (λ, P1) and the second variation curve T TMU After the first temperature difference ΔT′ between (λ, P2), the first change curve T TMU By shifting (λ, P1) upwards by 0.625ΔT′, we can obtain the curve T showing the relationship between the wavelength of the laser and the core temperature of the laser. LD (λ).

[0122] To enable accurate measurement of the laser core temperature without affecting laser operation, this specification also provides a corresponding measurement system, as detailed in the embodiments below. Figure 9 The diagram shows a structural schematic of a laser core temperature measurement system. The measurement system 90 enables non-contact measurement of the core temperature of a laser 9A. The laser 9A can be housed within a laser detection device (not shown) without requiring disassembly of the device. The measurement system 90 may include: a storage unit 91, a wavelength detection unit 92, and a processing unit 93, wherein:

[0123] The storage unit 91 is adapted to store the change curve of the wavelength of the laser 9A and the core temperature of the laser 9A, wherein the change curve of the wavelength of the laser 9A and the core temperature of the laser 9A is obtained by controlling the laser 9A to operate at different power levels.

[0124] The wavelength detection unit 92 is adapted to detect the output wavelength of the laser 9A;

[0125] The processing unit 93 is adapted to obtain the core temperature of the laser 9A based on the output wavelength of the laser 9A and according to the curve of the change between the wavelength of the laser 9A and the core temperature of the laser 9A.

[0126] Using the aforementioned measurement system 90, since the storage unit 91 stores the relationship between the wavelength of the laser 9A and the core temperature of the laser, and the wavelength detection unit 92 does not need to contact the laser 9A to obtain the output wavelength of the laser 9A, the processing unit 93 can then obtain the core temperature of the laser 9A based on the change curve of the laser 9A's wavelength and its core temperature. Therefore, the actual measurement process will not affect the normal operation of the laser 9A. If the laser 9A is installed in a device, such as a laser detection device like a lidar, the core temperature of the laser 9A during normal operation can be obtained conveniently and accurately without disassembling the laser detection device.

[0127] In a specific implementation, the measurement system 90 may further include: a control unit 94 and a temperature measurement unit 95, wherein:

[0128] The control unit 94 is adapted to control the laser 9A to operate at a first power and a second power, respectively.

[0129] The temperature measurement unit 95 is located at a different position from the laser 9A and forms a thermal resistance network with the laser 9A. It is adapted to detect the temperature at the corresponding temperature measurement position when the laser 9A is working at the first power and the second power, and output the temperature to the processing unit 93.

[0130] The wavelength detection unit 92 is also adapted to detect the output wavelength of the laser 9A when the laser 9A operates at the first power and the second power, respectively;

[0131] The processing unit 93 is adapted to obtain a first change curve and a second change curve based on the detection results of the temperature measurement unit 95 and the wavelength detection unit 92 when the laser 9A operates at a first power and a second power, and to obtain and store the change curve of the wavelength of the laser 9A versus the core temperature of the laser 9A in the storage unit 91 according to the first change curve and the second change curve; wherein, the first change curve is the change curve of the output wavelength of the laser 9A at the first power versus the temperature measured by the temperature measurement unit, and the second change curve is the change curve of the output wavelength of the laser 9A at the second power versus the temperature measured by the temperature measurement unit.

[0132] For specific measurement procedures, please refer to the specific application scenario examples in the aforementioned measurement method embodiments, which will not be described in detail here.

[0133] Using the above-mentioned measurement system 90, the laser 9A is controlled by the control unit 94 to operate at two power levels. By reading the temperature from the temperature measurement unit located at different positions from the laser, the drift curve of the laser's wavelength as a function of its core temperature can be obtained. This dual-power measurement process is simple, requires no disassembly, does not affect the normal operation of the laser, and can more accurately reflect the core temperature of the laser during normal operation.

[0134] In specific implementations, the temperature measuring unit 95 can be a thermistor with a negative temperature coefficient (NTC), which can be simply referred to as an NTC resistor. The temperature value can be obtained by reading its corresponding electrical parameters (the resistance is determined from the electrical parameters, and there is a definite correspondence between resistance and temperature). The temperature measuring unit can also be a thermocouple, or other types of temperature sensors capable of measuring temperature. The embodiments in this specification do not limit the specific type of the temperature measuring unit.

[0135] NTC refers to a thermistor with a negative temperature coefficient, where the resistance decreases exponentially with increasing temperature. This material can be a semiconductor ceramic produced by thoroughly mixing, molding, and sintering two or more metal oxides such as manganese, copper, silicon, cobalt, iron, nickel, and zinc, resulting in a thermistor with a negative temperature coefficient (NTC). Its resistivity and material constant vary depending on the material composition ratio, sintering atmosphere, sintering temperature, and structural state. The NTC resistor can also be made using non-oxide-based NTC thermistor materials such as silicon carbide, tin selenide, and tantalum nitride. It is understood that the above is merely an exemplary description of the specific implementation of the NTC resistor, and the embodiments in this specification do not limit the materials, composition, or manufacturing process of the NTC resistor.

[0136] In a specific implementation, the processing unit 93 is adapted to obtain the distance between the first change curve and the second change curve along the temperature axis to obtain a first temperature difference; the first change curve is shifted along the temperature axis by a preset distance to obtain the change curve of the laser wavelength and the laser core temperature, wherein the second temperature difference corresponding to the preset distance satisfies the following relationship with the first temperature difference:

[0137] ΔT1′=1 / (x-1)ΔT′;

[0138] Wherein, ΔT1′ represents the second temperature difference, ΔT′ represents the first temperature difference, x represents the ratio of the second power to the first power, and x>1.

[0139] The processing unit 93 performs a translation transformation based on the first and second change curves to obtain a more detailed example of the change curve of the laser wavelength versus the laser core temperature. For more detailed examples, please refer to the application examples of the measurement method in the foregoing embodiments, which will not be described further here.

[0140] In specific implementations, the temperature detection unit may include multiple temperature sensors. If the laser detection device includes multiple lasers, a corresponding temperature sensor can be set for each laser, and each laser can form a thermal resistance network with its nearest temperature sensor. The core temperature of each laser can be measured using the measurement methods and systems provided in the embodiments of this specification.

[0141] In some embodiments described herein, the wavelength detection unit may specifically be a spectrometer. It should be noted that the embodiments in this specification do not limit the specific type of wavelength detection unit, as long as it enables non-contact measurement of the laser wavelength.

[0142] In specific implementation, we will continue to refer to Figure 9 The measurement system 90 may further include a diffuse reflection unit 96, wherein the laser emitted by the laser is reflected by the diffuse reflection unit 96 and then detected by the wavelength detection unit 92. As an optional example, the diffuse reflection unit may include white paper.

[0143] If the spectrometer is directly pointed at the laser, it is slightly sensitive to angle. By adding a diffuse reflection unit, the influence of angle can be weakened. On the one hand, since the spectrum of the laser may differ in different directions, the diffuse reflection unit can convert direct light into diffuse reflection, thereby weakening the influence of angle. On the other hand, since the fiber optic probe of the spectrometer is more prone to saturation when the light is directly incident, and the measurement position is far from the light spot, the obtained spectral curve has more spikes. After being reflected by the diffuse reflection unit, the direct light becomes diffuse reflection, and the probe can be aligned with the light spot, thus making the detected spectral curve smoother.

[0144] Reference Figure 10 (a) If no diffuse reflection unit is used during the measurement process, and the output wavelength of the laser LD0 in the lidar H0 is detected by the spectrometer probe SP0, where the spectrometer probe SP0 is directly aimed at the laser emitted by the laser LD0, the detected spectral distribution is as follows: Figure 10 As shown in b), the horizontal axis corresponds to the wavelength distribution of the laser, and the vertical axis corresponds to the intensity of the light at the corresponding wavelength. The spectral curve of each measurement can be obtained, which shows that it has many spikes and is not smooth enough.

[0145] And reference Figure 11 (a) In the measurement system, a white paper P0 is used to diffusely reflect the laser emitted by the laser LD0 in the lidar H0. The angle of the spectrometer probe SP0 is adjusted to align the probe with the light spot, and the detected spectral distribution is as follows: Figure 11 As shown in b), it can be seen that relative to Figure 10 (b) The resulting spectral curves for each measurement are smoother and flatter.

[0146] In practice, the wavelength corresponding to each measurement is obtained based on the spectral curve obtained from each measurement. Figure 10 b and Figure 11 Different gray levels in b correspond to different measurement results, thus obtaining the λ mentioned above. 1 n and λ 2 Due to the asymmetry of the spectral curves detected by the spectrometer, the output wavelength of the laser can be obtained from the detected spectral curves through methods such as weighted averaging.

[0147] As a preferred example, the wavelength detection unit 92 is adapted to acquire the output wavelength of the laser 9A when the laser detection device is in normal operating mode.

[0148] This specification also provides a laser detection device, see embodiments thereof. Figure 12 The schematic diagram of the laser detection device shown illustrates that, in this embodiment, the laser detection device LDA may include a transmitter S0 and a controller C0, wherein:

[0149] The transmitting device S0 includes a laser LD;

[0150] The controller C0 is coupled to the transmitter device S0 and is adapted to control the laser LD to operate at different power levels according to preset transmission control parameters, so as to obtain the wavelength and core temperature variation curve of the laser LD; and to obtain the core temperature of the laser LD based on the obtained output wavelength of the laser LD and the wavelength and core temperature variation curve of the laser LD.

[0151] In a specific implementation, the transmitter device S0 further includes: a printed circuit board PCB0 and a temperature measurement unit TMU, wherein:

[0152] The printed circuit board PCB0, and the laser LD is disposed on the printed circuit board PCB0;

[0153] The temperature measurement unit (TMU) is located on the printed circuit board (PCB0) at a different position from the laser (LD), forming a thermal resistance network with the laser (LD), and is suitable for measuring the temperature at its location.

[0154] In a specific implementation, the printed circuit board PCB0 may be provided with multiple lasers LD, and the temperature measurement unit TMU includes multiple temperature sensors TS corresponding to the multiple lasers respectively.

[0155] As an optional example, the multiple lasers can be arranged linearly on the printed circuit board PCB0, form a laser array, or be irregularly arranged; the specific arrangement can be set according to specific requirements. Correspondingly, a corresponding number of temperature sensors can be set on the printed circuit board PCB0, and each laser can form a thermal resistance network with its nearest temperature sensor. Figure 12 As shown, multiple lasers LD1 to LDn and temperature sensors TS1 to TSn are correspondingly arranged on the printed circuit board PCB0. The temperature sensors TS1 to TSn can be used to obtain the corresponding measured temperature during the emission process of lasers LD1 to LDn, and thus the relationship curve between the core temperature of lasers LD1 to LDn and their wavelength can be obtained.

[0156] While the embodiments of the present invention have been disclosed above, the present invention is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method of measuring the temperature of a laser core, characterized in that, The measurement method comprises: Step A, by controlling the laser to work at different powers respectively, obtaining the change curve of the output wavelength of the laser at different powers with the temperature measured by the temperature measurement unit, and according to the change curve of the output wavelength of the laser at different powers with the temperature measured by the temperature measurement unit and the temperature drift characteristic of the laser, the change curve of the wavelength of the laser and the core temperature of the laser is obtained by translation transformation, wherein the temperature measurement unit and the laser are located at different positions, and the laser and the temperature measurement unit form a thermal resistance network; Step B, obtaining the output wavelength of the laser; Step C, based on the output wavelength of the laser, according to the change curve of the wavelength of the laser and the core temperature of the laser, the core temperature of the laser is obtained.

2. The measurement method according to claim 1, characterized in that, The step A comprises: Step A1, controlling the laser to work at a first power and a second power respectively, obtaining a first change curve and a second change curve, wherein the first change curve is the change curve of the output wavelength of the laser at the first power with the temperature measured by the temperature measurement unit, and the second change curve is the change curve of the output wavelength of the laser at the second power with the temperature measured by the temperature measurement unit; Step A2, according to the first change curve and the second change curve and the temperature drift characteristic of the laser, the change curve of the wavelength of the laser and the core temperature of the laser is obtained by translation transformation.

3. The measurement method according to claim 2, characterized in that, The step A1 comprises: Step A11, controlling the laser to work at a first power, obtaining the output wavelength of the laser, and obtaining the temperature value of the temperature measurement unit, obtaining the first change curve of the output wavelength of the laser with the temperature value of the temperature measurement unit; Step A12, controlling the laser to work at a second power, obtaining the output wavelength of the laser, and obtaining the temperature value of the temperature measurement unit, obtaining the second change curve of the output wavelength of the laser with the temperature value of the temperature measurement unit.

4. The method of claim 3, wherein the laser is provided in a laser probe device. The step A11 comprises: controlling the laser to start working at a first power, and obtaining the first change curve of the output wavelength of the laser with the temperature value of the temperature measurement unit in the process from starting the laser to the laser detection device being at a stable temperature; The step A12 comprises: controlling the laser to start working at a second power, and obtaining the second change curve of the output wavelength of the laser with the temperature value of the temperature measurement unit in the process from starting the laser to the laser detection device being at a stable temperature.

5. The measuring method according to any one of claims 2 to 4, characterized in that, The step A2 comprises: Step A21, obtaining the distance of the first change curve and the second change curve in the temperature axis direction, obtaining a first temperature difference; Step A22, translating the first change curve along the temperature axis direction by a preset distance to obtain the change curve of the wavelength of the laser and the core temperature of the laser, wherein the second temperature difference corresponding to the preset distance and the first temperature difference satisfy the following relationship: T1' = 1 / (x-1) T'; wherein T1' represents the second temperature difference, T' represents the first temperature difference, x represents the proportional relationship between the second power and the first power, and x >

1.

6. The measurement method according to claim 5, characterized in that, wherein, x is 2.

7. The method of claim 1, wherein, The laser is arranged in a laser detection device, and the step B comprises: controlling the laser detection device to be in a normal use mode, and obtaining an output wavelength of the laser.

8. A system for measuring the temperature of a laser core, said laser being arranged in a laser detection device, characterized in that The measurement system comprises: a control unit adapted to control the laser to work at different powers respectively; a temperature measurement unit located at different positions from the laser and forming a thermal resistance network with the laser, and adapted to detect temperatures at corresponding temperature measurement positions of the laser when the laser works at different powers respectively, and output to a processing unit; a storage unit adapted to store a wavelength-temperature variation curve of the laser, wherein the wavelength-temperature variation curve of the laser is obtained by controlling the laser to work at different powers respectively; a wavelength detection unit adapted to detect the output wavelength of the laser; a processing unit adapted to obtain a variation curve of the output wavelength of the laser at different powers with respect to the temperature measured by the temperature measurement unit, and obtain the wavelength-temperature variation curve of the laser by translation transformation based on the variation curve of the output wavelength of the laser at different powers with respect to the temperature measured by the temperature measurement unit and the temperature drift characteristic of the laser, and store the wavelength-temperature variation curve of the laser into the storage unit, and obtain the core temperature of the laser based on the output wavelength of the laser and the wavelength-temperature variation curve of the laser.

9. The measurement system according to claim 8, wherein: the control unit is adapted to control the laser to work at a first power and a second power respectively; the temperature measurement unit is adapted to detect temperatures at corresponding temperature measurement positions of the laser when the laser works at the first power and the second power respectively, and output to the processing unit; the wavelength detection unit is further adapted to detect the output wavelength of the laser when the laser works at the first power and the second power respectively; the processing unit is adapted to obtain a first variation curve and a second variation curve based on the detection results of the temperature measurement unit and the wavelength detection unit when the laser works at the first power and the second power respectively, and obtain the wavelength-temperature variation curve of the laser by translation transformation based on the first variation curve and the second variation curve and the temperature drift characteristic of the laser, and store the wavelength-temperature variation curve of the laser into the storage unit; wherein the first variation curve is a variation curve of the output wavelength of the laser at the first power with respect to the temperature measured by the temperature measurement unit, and the second variation curve is a variation curve of the output wavelength of the laser at the second power with respect to the temperature measured by the temperature measurement unit.

10. The measurement system of claim 9, wherein, The temperature measurement unit comprises at least one of the following types: a thermistor with a negative temperature coefficient; a thermocouple.

11. The measurement system of claim 9, wherein, The processing unit is adapted to obtain a first temperature difference by obtaining a distance between the first change curve and the second change curve in a temperature axis direction; and obtain a change curve of the wavelength of the laser and the core temperature of the laser by translating the first change curve along the temperature axis direction by a preset distance, wherein a second temperature difference corresponding to the preset distance and the first temperature difference satisfy the following relationship: T1' = 1 / (x-1) T' wherein T1' represents the second temperature difference, T' represents the first temperature difference, x represents the proportional relationship between the second power and the first power, and x >

1.

12. The measurement system of claim 8 or 9, wherein, Also comprising: A diffuse reflection unit, the laser emitted by the laser is reflected by the diffuse reflection unit and then detected by the wavelength detection unit.

13. The measurement system of claim 8, wherein, The wavelength detection unit is adapted to obtain the output wavelength of the laser when the laser detection device is in a normal use mode.

14. A laser detection device, characterized by Comprising: A transmitting end device and a controller, wherein: The transmitting end device comprises: A laser; A printed circuit board, and the laser is arranged on the printed circuit board; and A temperature measurement unit arranged at a position different from the laser on the printed circuit board, and forming a thermal resistance network with the laser, and adapted to measure the temperature at the position; The controller is coupled to the transmitting end device, and is adapted to control the laser to work at different powers according to preset transmission control parameters, obtain a change curve of the output wavelength of the laser at different powers with the temperature measured by the temperature measurement unit, and obtain a change curve of the wavelength of the laser and the core temperature of the laser by translation transformation according to the change curve of the output wavelength of the laser at different powers with the temperature measured by the temperature measurement unit and the temperature drift characteristic of the laser; and obtain the core temperature of the laser based on the obtained output wavelength of the laser according to the change curve of the wavelength of the laser and the core temperature of the laser.

15. The laser probing device of claim 14, wherein, A plurality of lasers are arranged on the printed circuit board, and the temperature measurement unit comprises a plurality of temperature sensors corresponding to the plurality of lasers, respectively.

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