Laser temperature control system and method

Abstract

A system comprising: a processor hosting a program module including a laser temperature control algorithm; a laser device communicating with the processor and operated to emit a laser beam; and a laser heating / cooling unit coupled to the laser device and communicating with the processor. At least one first temperature sensor communicates with the processor and is configured to measure the temperature of the laser device. Optionally, one or more second temperature sensors communicate with the processor and are configured to measure the temperature of the laser heating / cooling unit. At least one third temperature sensor communicates with the processor and is configured to measure the temperature of the ambient temperature outside the laser device. The laser temperature control algorithm operates to perform a preheating process during startup of the laser device and a cooling process during operation of the laser device.

Description

Background Technology

[0001] Some LiDAR (Light Detection and Ranging) technologies require stable laser sources with narrow linewidths and high power output. Given the typically high-temperature sensitivity of laser operation, controlling and maintaining the laser temperature within a desired range is crucial. For example, most lasers operate optimally within a specific temperature range, and deviations from this range can lead to various problems. At low temperatures, laser efficiency may decrease, resulting in reduced output power. This decrease in output power affects the optical signal, thereby reducing the signal-to-noise ratio of the laser system.

[0002] Furthermore, temperature changes can cause the laser's frequency to drift or deviate from its desired value, negatively impacting the sensitivity of sensor systems using the laser. Additionally, severe temperature fluctuations can trigger mode hopping, where the laser alternates between different operating modes, potentially affecting beam quality. Besides temperature-related issues, uncontrolled operating conditions can cause several other performance and reliability problems with the laser.

[0003] Some LiDAR systems utilize high-power lasers with integrated thermal management systems that include preheating and cooling mechanisms to mitigate temperature-related issues and maintain stable temperatures. However, some operating conditions, such as temperature and pressure, can change significantly, especially in aircraft applications or in extremely cold weather.

[0004] In other systems, the laser includes a built-in proportional-integral-derivative (PID) controller that attempts to regulate the temperature based on sensor measurements. However, due to rapid fluctuations in external temperature and pressure, current methods still require a significant warm-up period, such as more than 40 minutes, before the system can operate effectively. This delay limits the operating window and remains a concern for users, especially in time-sensitive applications.

[0005] Therefore, more efficient temperature control strategies are needed to improve the responsiveness and overall performance of laser systems. Summary of the Invention

[0006] A system comprising: a processor hosting a program module including a laser temperature control algorithm; a laser device operatively communicating with the processor and operated to emit a laser beam; and a laser heating / cooling unit operatively coupled to the laser device and operatively communicating with the processor. At least one first temperature sensor operatively communicates with the processor and is configured to measure the temperature of the laser device. Optionally, one or more second temperature sensors operatively communicate with the processor and are configured to measure the temperature of the laser heating / cooling unit. At least one third temperature sensor operatively communicates with the processor and is configured to measure the temperature of the ambient temperature outside the laser device. The laser temperature control algorithm operates to perform a preheating process during startup of the laser device and a cooling process during operation of the laser device. Attached Figure Description

[0007] The features of the invention will become apparent to those skilled in the art from the following description with reference to the accompanying drawings. It should be understood that the drawings illustrate only typical embodiments and are therefore not intended to limit the scope of the invention. The invention will be described with additional features and details using the drawings, wherein:

[0008] Figure 1 This is a block diagram of a system for laser temperature control according to one implementation scheme;

[0009] Figure 2 It is a flowchart based on a specific implementation of a process for performing a preheating function during the startup of a laser device;

[0010] Figure 3 This is a flowchart of a process for performing a cooling function during the operation of a laser device, according to another specific embodiment;

[0011] Figure 4 This is shown according to an example such as by using Figure 1 The curves showing the preheating and operation of the laser device in low-temperature weather.

[0012] Figure 5 This is to illustrate, according to another example, such as by using Figure 1 The curves of preheating and operation of the laser device under normal temperature conditions;

[0013] Figure 6 This is to illustrate, according to another example, such as by using Figure 1 The graph shows the preheating and operation of the laser device in low-temperature weather, where the temperature changes rapidly over time.

[0014] Figure 7This is to illustrate, according to another example, such as by using Figure 1 The graph shows the preheating and operation of the laser device in ambient temperature weather, where the temperature changes rapidly over time;

[0015] Figure 8 This is a block diagram of a portion of an integrated control module in a laser subsystem according to one implementation scheme;

[0016] Figure 9 This is a block diagram of a system for laser temperature control according to another embodiment;

[0017] Figure 10 This is a flowchart of a method for performing a laser preheating function according to another specific embodiment; and

[0018] Figure 11 This is a flowchart of a method for performing temperature control during laser operation, according to another specific implementation. Detailed Implementation

[0019] In the following detailed description, the embodiments are fully described to enable those skilled in the art to practice the invention. It should be understood that other embodiments may be utilized without departing from the scope of the invention. Therefore, the following detailed description should not be considered limiting.

[0020] This article describes systems and methods for laser temperature control.

[0021] In various applications, laser systems need to reach a target temperature before operation can begin. This is typically manually controlled and heavily reliant on the engineer's experience, which can lead to significant variations in warm-up time. Furthermore, external conditions can significantly affect the time required for a laser system to reach its optimal temperature. For example, during colder months, a laser system may take more than two hours to heat up to the desired operating temperature.

[0022] In this method, the laser temperature control process is automated and optimized. This ensures that the laser system quickly reaches and maintains optimal conditions during operation, regardless of environmental changes. This method provides rapid and reliable preheating of the laser, as well as precise temperature regulation. This system can accelerate the laser preheating process and consistently maintain the laser at the ideal operating temperature.

[0023] This system includes temperature sensors for both the laser chamber and the surrounding environment. These temperature sensors relay measurements at a predetermined or desired frequency corresponding to the frequency of temperature readouts. The system also includes a control system equipped with an optimized control algorithm that guides the temperature control settings to increase or decrease their power. One or more temperature control systems (such as heaters, coolers, fans, thermoelectric coolers, or liquid cooling systems) operate based on these instructions to regulate the power to the desired target frequency. The control algorithm may be housed in a chip or microcircuit.

[0024] A method for setting the power level of a temperature control device via a control algorithm depends on both the ambient temperature and the device temperature. In one embodiment, the power setting employs a two-step approach. When the temperature difference between the ambient temperature and the device temperature is large (exceeding a preset level), power overshoot or maximum power is applied to the heating or cooling system. Once the temperature difference decreases to a specified level, the power of the temperature control device is reduced. Based on continuous temperature measurements, the power of the temperature control device is adjusted to maintain the laser device temperature at optimal conditions. In one embodiment, a self-learning algorithm can be used to achieve precise control of the laser operating temperature based on this method.

[0025] In one implementation, the device temperature, ambient temperature, and power settings for heating / cooling at each operation are stored in a memory chip. The control algorithm uses this historical data to determine the optimal power setting for the temperature control element. In another implementation, the control algorithm calculates the rate of change of the device temperature, compares it to the current and / or past ambient and device temperatures, and uses this information to determine or predict new temperature setting values ​​for subsequent steps.

[0026] In another implementation, the control algorithm includes an embedded proportional-integral-derivative (PID) controller. This controller is a control loop feedback mechanism commonly used in industrial control systems, although it varies in specific implementations. The proportional term of the PID controller is represented by the following equation:

[0027] .

[0028] The integral term is Ki × error_integral, and the derivative term is Kd × error_derivative. These terms are based on sensor readings and the power regulation frequency (f). T ) to optimize.

[0029] In another implementation, the PID controller functionality is integrated into the hardware via a programmable logic controller (PLC) system. The proportional term used in the PID controller is set within a predetermined range. In yet another implementation, the parameters selected from the control algorithm and the PID depend on the frequency of the device's power setting adjustments. Here, "desired step size" refers to the desired change in power setting for each adjustment.

[0030] Further details of various embodiments are described below with reference to the accompanying drawings.

[0031] Figure 1 A system 100 for laser temperature control according to an example embodiment is illustrated. System 100 typically includes at least one processor 110 that hosts a program module 112 including a laser temperature control algorithm 114. A laser operation unit 120 is operatively coupled to the processor 110. Laser operation unit 120 may be part of a ground-based laser system, such as for high-altitude atmospheric sensing. Alternatively, laser operation unit 120 may be part of an air data sensing system, such as an airborne air data sensing system for aircraft.

[0032] The laser operating unit 120 includes a laser device 122 operatively in communication with the processor 110 and configured to emit a laser beam. The laser device 122 may be a high-power laser or a semiconductor laser, etc. In one embodiment, the laser device 122 may be part of a LiDAR (Light Detection and Ranging) device. A laser heating / cooling unit 124 is operatively coupled to the laser device 122 and operatively in communication with the processor 110. The laser heating / cooling unit 124 operates to provide heat to the laser device 122 by increasing current through DC injection. The laser heating / cooling unit 124 also operates to provide cooling to the laser device 122 using a refrigerator and a cooling fan, etc.

[0033] Furthermore, the laser operation unit 120 includes at least one first temperature sensor 126, such as a laser temperature sensor (e.g., a thermistor), and is configured to measure the temperature of the laser device 122. The first temperature sensor 126 is operatively in communication with the processor 110 and provides temperature information to the laser temperature control algorithm 114.

[0034] Optionally, at least one second temperature sensor 128 (such as a heating / cooling temperature sensor) may be configured to measure the temperature of the laser heating / cooling unit 124. The second temperature sensor 128 is operatively in communication with the processor 110 and provides temperature information to the laser temperature control algorithm 114.

[0035] At least one third temperature sensor 130 (such as an ambient temperature sensor) is configured to measure the temperature of the surrounding environment outside the laser operating unit 120. The third temperature sensor 130 is operatively in communication with the processor 110 and provides temperature information to the laser temperature control algorithm 114.

[0036] As described in further detail below, the laser temperature control algorithm 114 operates to perform a preheating process during the startup of the laser device 122. Furthermore, the laser temperature control algorithm 114 operates to perform a cooling process during the operation of the laser device 122.

[0037] When the laser device 122 is a semiconductor laser, preheating to the laser's desired operating temperature is achieved using a current injection technique. For example, by passing current through a laser diode, the laser diode device heats up due to the resistance of the laser diode's semiconductor material. Current injection is advantageous because it directly affects the active region of the laser diode, thereby ensuring that the laser diode reaches the optimal temperature for efficient operation.

[0038] During operation, the temperature of the laser device 122 may increase significantly, which can affect its performance and lifespan. Several cooling methods can be employed to manage this heat. For example, liquid cooling methods can be used, which involve circulating a coolant through pipes or channels in contact with the laser device or its heat sink. Liquid cooling methods can be highly efficient for high-power lasers. Another example cooling method involves air cooling using a heat sink attached to the laser device to dissipate heat from it. Another example cooling method is microchannel cooling, which uses tiny channels to circulate coolant close to the active region of the laser device, providing efficient heat removal. Furthermore, combining two or more of these cooling methods can help maintain the laser device at a stable temperature, ensuring consistent performance and preventing damage.

[0039] Figure 2 This is a process 200 specifically implemented according to the example for performing a preheating function during the startup of a laser device (such as by laser temperature control algorithm 114). Figure 1 The flowchart for the execution of the process is as follows. Process 200 includes receiving a first laser temperature measurement result from the laser temperature sensor at a first time step (box 210); and receiving a second laser temperature measurement result from the laser temperature sensor at a second time step (box 212). Process 200 calculates the laser temperature change value by determining the difference between the first laser temperature measurement result and the second laser temperature measurement result (box 214).

[0040] Process 200 further includes receiving a first ambient temperature measurement result from an ambient temperature sensor at a first time step (box 216); and receiving a second ambient temperature measurement result from an ambient temperature sensor at a second time step (box 218). Then, process 200 calculates the ambient temperature change value by determining the difference between the first ambient temperature measurement result and the second ambient temperature measurement result (box 220).

[0041] It should be noted that the steps of process 200 described with respect to boxes 210, 212, 214 and 216, 218, 220 may be performed serially or in parallel (i.e., simultaneously). Furthermore, it should be noted that the time steps in process 200 may be adaptive, i.e., they may be varied within a given range.

[0042] Subsequently, process 200 compares the laser temperature change with the ambient temperature change to determine the temperature difference change (box 222). In response to determining that the temperature difference change is greater than zero, process 200 increases the current / power sent to the laser device until the laser device temperature stabilizes (box 224). In response to determining that the temperature difference change is less than or equal to zero, process 200 decreases the current / power sent to the laser device until the laser device temperature stabilizes (box 226). During the laser device warm-up period, process 200 may repeat additional time steps, the duration of which can be user-selectable.

[0043] Since the laser heater / cooler power is set after each given time step, the steps of process 200 described for blocks 224 and 226 should not be performed until the temperature of the laser device stabilizes. This should be done in the next step (when the new settings become available).

[0044] Figure 3 This is a specific implementation according to another example for use in laser devices (such as laser device 122). Figure 1The flowchart below describes a process 300 for performing a cooling function during operation of the laser device. Process 300 includes receiving a first laser temperature measurement result from a laser temperature sensor at a first time step (box 310); and acquiring a target operating temperature value for the laser device at the first time step (box 312). Process 300 also includes receiving an ambient temperature measurement result from an ambient temperature sensor at the first time step (box 314). Subsequently, process 300 calculates a temperature difference between the first laser temperature measurement result and the target operating temperature value (box 316); and determines a temperature difference threshold based on the target operating temperature value and the ambient temperature measurement result (box 318). Then, process 300 calculates a change in cooling current / power based on the temperature difference value and the temperature difference threshold (box 320). Process 300 adjusts the cooling current / power as needed based on the calculated change in cooling current / power to ensure stable operation of the laser device (box 322). During operation of the laser device, process 300 can repeat additional time steps, the duration of which can be user-selectable.

[0045] It should be noted that the steps of process 300 described in boxes 310, 312, 314, 316, 318 and 320 can be performed serially or in parallel.

[0046] Figures 4 to 7 An example of laser device temperature measurement based on the previously described algorithm and hardware architecture is illustrated. Results show that this method enables the laser device to quickly reach operational readiness and maintain optimal operating conditions, regardless of whether measurements are taken in normal or cold weather or how ambient temperature fluctuates.

[0047] Figure 4 This is graph 400 illustrating the preheating and operation of a laser device in low-temperature weather (-10°C) according to an example, such as by using this system and method. Graph 400 shows temperature (°C) and power (W) relative to time (hours). The laser device temperature is represented by curve 410, the ambient temperature by curve 412, and the applied power by curve 414. As shown, when the applied power is high at the start of the preheating operation, the system rapidly reaches the target laser temperature of 30°C (approximately 0.4 hours). Then, after reaching the target laser temperature, the applied power is reduced to maintain optimal operating conditions.

[0048] Figure 5This is graph 500 illustrating the preheating and operation of a laser device at ambient temperature (10°C) according to another example, such as using this system and method. Graph 500 shows temperature and power relative to time. The laser device temperature is represented by curve 510, the ambient temperature by curve 512, and the applied power by curve 514. As shown, when the applied power is high at the start of the preheating operation, the system rapidly reaches the target laser temperature of 30°C (approximately 0.3 hours). Then, after reaching the target laser temperature, the applied power is reduced to maintain optimal operating conditions.

[0049] Figure 6 This is graph 600 illustrating the preheating and operation of a laser device in low-temperature weather according to another example, such as using this system and method, where the temperature changes rapidly over time. Graph 600 shows temperature and power relative to time. The laser device temperature is represented by curve 610, the ambient temperature by curve 612, and the applied power by curve 614. As shown, when the applied power is high at the start of the preheating operation, the system rapidly reaches the target laser temperature of 30°C (approximately 0.4 hours). Then, after reaching the target laser temperature, the applied power is reduced to maintain optimal operating conditions.

[0050] Figure 7 This is graph 700 illustrating a preheating operation of a laser device in ambient weather using this system and method, according to another example, where the temperature changes rapidly over time. Graph 700 shows temperature and power relative to time. The laser device temperature is represented by curve 710, the ambient temperature by curve 712, and the applied power by curve 714. As shown, when the applied power is high at the start of the preheating operation, the system rapidly reaches the target laser temperature of 30°C (approximately 0.3 hours). Then, after reaching the target laser temperature, the applied power is reduced to maintain optimal operating conditions.

[0051] Figure 8 The following example implementation illustrates a portion of the integrated control module 800 in the laser subsystem and relates to a heater setup. However, the same approach applies to a cooler setup. When the laser device is in operation and the internal temperature rises, additional cooling may be required to lower the laser temperature.

[0052] like Figure 8 As shown, the integrated control module 800 includes multiple temperature sensors 804, a heater / cooler fan unit 806 communicating with the temperature sensors 804, and an optimization algorithm 808 for laser temperature control. The algorithm 808 collects heating / cooling power (P) from the heater / cooler fan unit 806. h / c), and collects temperature information from temperature sensor 804, including device temperature (T). d ) and ambient temperature (T) a Algorithm 808 also collects the target temperature (T) of the laser device. T The target temperature can be selected by the user. Algorithm 808 processes the collected temperature information and outputs a new power level setting at 810, which is sent to the heater / cooler fan unit 806 as needed to adjust the temperature of the laser device. Furthermore, algorithm 808 outputs an optimized frequency (f) at 812. T This optimized frequency is fed back to the temperature information from the temperature sensor 804.

[0053] Figure 9 A system 900 for laser temperature control according to another example embodiment is illustrated. System 900 typically includes a controller 910, which includes a memory (storage device) and an embedded algorithm for laser temperature control. A laser module 920 is operatively coupled to the controller 910. The laser module 920 includes a laser device 922 operatively in communication with the controller 910. A laser heating / cooling unit 924 is operatively coupled to the laser device 922 and operatively in communication with the controller 910. The laser heating / cooling unit 924 is operated to heat the laser device 922 by direct current injection. The laser heating / cooling unit 924 is also operated to cool the laser device 922, such as by using a refrigerator.

[0054] In addition, the laser module 920 includes one or more laser temperature sensors 926 configured to measure the temperature of the laser device 922. The laser temperature sensors 926 communicate with the controller 910 and provide laser temperature information to an embedded algorithm. The laser module 920 also includes one or more coolant temperature sensors 928 configured to measure the temperature of the laser heating / cooling unit 924. The coolant temperature sensors 928 communicate with the controller 910 and provide coolant temperature information to the embedded algorithm. Furthermore, one or more ambient temperature sensors 930 are configured to measure the temperature of the surrounding environment outside the laser module 920. The ambient temperature sensors 930 operatively communicate with the controller 910 and provide ambient temperature information to the embedded algorithm.

[0055] During operation of system 900, temperature sensors 926, 928, and 930 report temperature measurements at each time step to controller 910, and laser device 922 reports zero (0) operating power for preheating mode to controller 910. Controller 910 sends feedback to each of temperature sensors 926, 928, and 930 and laser device 922, including the size of the time step used. Temperature sensors 926, 928, and 930 report temperature measurements using the time step assigned by controller 910. Controller 910 also sends current / power settings for laser heating / cooling unit 924 to enable laser preheating operation and to provide a stable temperature during normal laser operation, such as for laser cooling operation. For example, DC injection can be used when an increase in laser temperature is required. The increase in current that produces the increased laser temperature is determined by controller 910. The laser operating target temperature 940, as a set value, is input to the controller 910 and used by an embedded algorithm to calculate the current / power setting of the laser heating / cooling unit 924.

[0056] Figure 10 This is a flowchart of a method 1000 for performing a laser preheating function, specifically implemented according to another example. Method 1000 includes the following steps: reading the current laser temperature (T... l ) and current ambient temperature (T) a ), and then the temperature T l and T a With respect to the target operating temperature (T) of the laser t The comparison is performed (box 1010). Method 1000 calculates the laser temperature change (dT) by comparing the current laser temperature with the laser temperature at a previous time step. l (Box 1012). Method 1000 also measures the change in ambient temperature (dT) by comparing the current ambient temperature with the ambient temperature at a previous time step. a (Box 1014). Then, method 1000 compares dT1 with the temperature difference threshold dT0 (which depends on T). t and T a (Box 1016). In particular, method 1000 may use both dT1 and dT0 to determine the current or power for the next step.

[0057] In response to determining that the difference between dT1 and dT0 is greater than zero, method 1000 provides a high current or power overshoot to preheat the laser (box 1018). Method 1000 is then repeated by returning to box 1010 at the next time step (dt). In response to determining that the difference between dT1 and dT0 is less than or equal to zero, method 1000 reduces the current / power (or uses a PID controller) until the laser temperature stabilizes (box 1020). Method 1000 is then repeated by returning to box 1010 at the next time step. The next time step can be determined from the previous few time steps of the laser temperature, and the time step size can also be updated.

[0058] Figure 11 This is a flowchart of a method 1100 for performing temperature control during laser operation, specifically implemented according to another example. Method 1100 includes reading the current laser temperature (TL) of the laser. l ), current ambient temperature (T) a ) and target operating temperature (T) t Steps (box 1110) of method 1100: Calculate T l With T t The temperature difference (dT1) between them (box 1112). Method 1100 determines the temperature difference depending on T. t With T a The temperature difference threshold dT0 is calculated (box 1114). Method 1100 calculates the cooling current / power variation required for subsequent steps (box 1116) and adjusts the cooling current / power to ensure stable laser operation (box 1118).

[0059] Then, method 1100 is repeated by returning to box 1110 at the next time step. Similarly, the next time step can be determined by the laser temperature over the past few time steps, and the time step size can also be updated.

[0060] The processing units and / or other computing devices used in the methods and systems described herein can be implemented using software, firmware, hardware, or suitable combinations thereof. The processing units and / or other computing devices may be supplemented or incorporated into specially designed application-specific integrated circuits (ASICs) or field-programmable gate arrays (FGPAs). In some embodiments, the processing units and / or other computing devices may communicate with other computing devices external to the navigation system via additional transceivers, such as computing devices associated with the management system or with other subsystems controlled by the management system. The processing units and / or other computing devices may also include or run with software programs, firmware, or other computer-readable instructions to perform the various processing tasks, computational, and control functions used in the methods and systems described herein.

[0061] The methods described herein can be implemented using computer-executable instructions (such as program modules or components) that are executed by at least one processor or processing unit. Typically, program modules include routines, programs, objects, data components, data structures, and algorithms that perform specific tasks or implement specific abstract data types.

[0062] Various procedural tasks, calculations, and instructions for generating other data used in performing the methods described herein may be implemented in software, firmware, or other computer-readable instructions. These instructions are typically stored on a suitable computer program product, including computer-readable media for storing computer-readable instructions or data structures. Such computer-readable media may be available media accessible by a general-purpose or special-purpose computer or processor or any programmable logic device.

[0063] Suitable computer-readable storage media may include, for example, non-volatile memory devices, including semiconductor memory devices such as random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), or flash memory devices; magnetic disks, such as internal hard disks or removable disks; optical disk storage devices, such as optical discs (CD), digital versatile optical discs (DVD), Blu-ray discs; or any other medium that can be used to carry or store desired program code in the form of computer-executable instructions or data structures.

[0064] Example Implementation Plan

[0065] Example 1 includes a system comprising: a processor hosting a program module including a laser temperature control algorithm; a laser device operatively communicating with the processor and operated to emit a laser beam; a laser heating / cooling unit operatively coupled to the laser device and operatively communicating with the processor; at least one first temperature sensor operatively communicating with the processor and configured to measure the temperature of the laser device; optionally, at least one second temperature sensor operatively communicating with the processor and configured to measure the temperature of the laser heating / cooling unit; and at least one third temperature sensor operatively communicating with the processor and configured to measure the temperature of the ambient temperature outside the laser device; wherein the laser temperature control algorithm operates to perform a preheating process during startup of the laser device and a cooling process during operation of the laser device.

[0066] Example 2 includes the system according to Example 1, wherein during the startup of the laser device, the preheating process includes: receiving a first laser temperature measurement result from the at least one first temperature sensor at a first time step; receiving a second laser temperature measurement result from the at least one first temperature sensor at a second time step; calculating a laser temperature change value by determining the difference between the first laser temperature measurement result and the second laser temperature measurement result; receiving a first ambient temperature measurement result from the at least one third temperature sensor at the first time step; receiving a second ambient temperature measurement result from the at least one third temperature sensor at the second time step; calculating an ambient temperature change value by determining the difference between the first ambient temperature measurement result and the second ambient temperature measurement result; and comparing the laser temperature change value with the ambient temperature change value to determine a temperature difference change value; increasing the current / power sent to the laser device in response to determining that the temperature difference change value is greater than zero until the temperature of the laser device stabilizes; and decreasing the current / power sent to the laser device in response to determining that the temperature difference change value is less than or equal to zero until the temperature of the laser device stabilizes.

[0067] Example 3 includes the system according to Example 1, wherein during the operation of the laser device, the cooling process includes: receiving a first laser temperature measurement result from the at least one first temperature sensor at a first time step; acquiring a target operating temperature value of the laser device at the first time step; receiving a first ambient temperature measurement result from the third temperature sensor at the first time step; calculating a temperature difference between the first laser temperature measurement result and the target operating temperature value; determining a temperature difference threshold based on the target operating temperature value and the first ambient temperature measurement result; calculating a change in cooling current / power based on the temperature difference and the temperature difference threshold; and adjusting the cooling current / power based on the calculated change to ensure stable operation of the laser device.

[0068] Example 4 includes a system according to any one of Examples 1 to 3, wherein the laser operating unit includes the laser device, the laser heating / cooling unit, the at least one first temperature sensor, and one or more second temperature sensors.

[0069] Example 5 includes the system according to Example 4, wherein the laser operating unit is part of a ground-based laser system for high-altitude atmospheric sensing.

[0070] Example 6 includes the system according to any one of Examples 4 to 5, wherein the laser operation unit is part of an airborne air data sensing system for an aircraft.

[0071] Example 7 includes a system according to any one of Examples 4 to 6, wherein the laser device is part of a light detection and ranging (LiDAR) device.

[0072] Example 8 includes a system according to any one of Examples 4 to 7, wherein the laser heating / cooling unit operates to provide heat to the laser device via DC injection.

[0073] Example 9 includes a system according to any one of Examples 4 to 8, wherein the laser heating / cooling unit operates to provide cooling to the laser device using a refrigerator, cooling fan, liquid cooling, or coolant.

[0074] Example 10 includes a system according to any one of Examples 1 to 9, wherein the processor includes a controller having memory.

[0075] Example 11 includes the system according to Example 10, wherein the controller includes a proportional-integral-derivative (PID) controller.

[0076] Example 12 includes a system according to any one of Examples 10 to 11, wherein the controller is configured to send feedback to the temperature sensor and the laser device, including the size of the time step used.

[0077] Example 13 includes a system according to any one of Examples 10 to 12, wherein the controller is configured to receive an operating target temperature for the laser device, the operating target temperature being used by the laser temperature control algorithm to calculate the current / power settings of the laser heating / cooling unit.

[0078] Example 14 includes the system according to Example 13, wherein the controller is configured to send the current / power setting to the laser heating / cooling unit to enable the preheating process during startup of the laser device and to enable the cooling process during operation of the laser device.

[0079] Example 15 includes a method for performing a laser preheating operation, the method comprising: receiving a first laser temperature measurement result from a laser temperature sensor at a first time step; receiving a second laser temperature measurement result from the laser temperature sensor at a second time step; calculating a laser temperature change value by determining the difference between the first laser temperature measurement result and the second laser temperature measurement result; receiving a first ambient temperature measurement result from an ambient temperature sensor at the first time step; receiving a second ambient temperature measurement result from the ambient temperature sensor at the second time step; calculating an ambient temperature change value by determining the difference between the first ambient temperature measurement result and the second ambient temperature measurement result; and comparing the laser temperature change value with the ambient temperature change value to determine a temperature difference change value; increasing the current / power transmitted to the laser device in response to determining that the temperature difference change value is greater than zero until the temperature of the laser device stabilizes; and decreasing the current / power transmitted to the laser device in response to determining that the temperature difference change value is less than or equal to zero until the temperature of the laser device stabilizes.

[0080] Example 16 includes the method according to Example 15, wherein the laser device is part of a ground-based laser system for high-altitude atmospheric sensing.

[0081] Example 17 includes the method according to Example 15, wherein the laser device is part of an airborne air data sensing system for an aircraft.

[0082] Example 18 includes a method for performing laser cooling operation, the method comprising: receiving a first laser temperature measurement result of a laser device from a laser temperature sensor at a first time step; acquiring a target operating temperature value of the laser device at the first time step; receiving an ambient temperature measurement result from an ambient temperature sensor at the first time step; calculating a temperature difference between the first laser temperature measurement result and the target operating temperature value; determining a temperature difference threshold based on the target operating temperature value and the ambient temperature measurement result; calculating a change in cooling current / power based on the temperature difference value and the temperature difference threshold; and adjusting the cooling current / power based on the calculated change in cooling current / power to ensure stable operation of the laser device.

[0083] Example 19 includes the method according to Example 18, wherein the laser device is part of a ground-based laser system for high-altitude atmospheric sensing.

[0084] Example 20 includes the method according to Example 18, wherein the laser device is part of an airborne air data sensing system for an aircraft.

[0085] This invention may be embodied in other specific forms without departing from its essential characteristics. The described embodiments are to be regarded in all respects as illustrative rather than restrictive. Therefore, the scope of the invention is indicated by the appended claims rather than the foregoing description. All variations within the meaning and scope of the equivalence of the claims are to be covered within its scope.

Claims

1. A system comprising: A processor that hosts a program module including a laser temperature control algorithm; A laser device that is operatively in communication with the processor and is operated to emit a laser beam; A laser heating / cooling unit is operatively coupled to the laser device and operatively communicates with the processor; At least one first temperature sensor, which is operatively in communication with the processor and configured to measure the temperature of the laser device; Optionally, at least one second temperature sensor is provided, which is operatively in communication with the processor and configured to measure the temperature of the laser heating / cooling unit. and At least one third temperature sensor, which is operatively in communication with the processor and configured to measure the temperature of the ambient environment outside the laser device; The laser temperature control algorithm operates to perform a preheating process during startup of the laser device and a cooling process during operation of the laser device.

2. A method for performing a laser preheating operation, the method comprising: At the first time step, the first laser temperature measurement result of the laser device is received from the laser temperature sensor; At the second time step, the second laser temperature measurement result is received from the laser temperature sensor; The laser temperature change is calculated by determining the difference between the temperature measurement results of the first laser and the temperature measurement results of the second laser. At the first time step, receive the first ambient temperature measurement result from the ambient temperature sensor; At the second time step, a second ambient temperature measurement result is received from the ambient temperature sensor; The change in ambient temperature is calculated by determining the difference between the first ambient temperature measurement result and the second ambient temperature measurement result; as well as The temperature change value of the laser is compared with the temperature change value of the environment to determine the temperature difference change value; In response to determining that the temperature difference change value is greater than zero, the current / power sent to the laser device is increased until the temperature of the laser device stabilizes; In response to determining that the temperature difference change is less than or equal to zero, the current / power sent to the laser device is reduced until the temperature of the laser device stabilizes.

3. A method for performing a laser cooling operation, the method comprising: At the first time step, the first laser temperature measurement result of the laser device is received from the laser temperature sensor; The target operating temperature value of the laser device is obtained at the first time step; At the first time step, receive the ambient temperature measurement result from the ambient temperature sensor; Calculate the temperature difference between the temperature measurement result of the first laser and the target operating temperature value; The temperature difference threshold is determined based on the target operating temperature value and the ambient temperature measurement results. The change in cooling current / power is calculated based on the temperature difference value and the temperature difference threshold. as well as The cooling current / power is adjusted based on the calculated changes in the cooling current / power to ensure stable operation of the laser device.

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