机载宽温域CO_(2)激光器温控方法

Temperature control method of CO_(2) laser operating in airborne wide temperature range

机载激光雷达是实现远距离大气精准监测的重要手段,CO_(2)激光器工作谱段与部分大气污染物和化学物质吸收谱一致,是大气监测激光雷达的重要光源。面向机载要求,在控制体积重量的条件下实现-40℃~55℃宽温域工作是机载CO_(2)激光器温控系统的设计难点。因此,本文提出一种以激光器性能和环境温度为设计输入,半导体热电制冷与强制风冷相结合的闭环温控方法。根据激光器、半导体热电制冷和强制风冷等的结构与传热特性,建立温控方法的有限元模型,基于此模型对激光器温控性能进行研究。对于55℃高温环境,温控系统工作25 min后,激光器温度控制在40℃;对于-40℃低温环境,温控系统在工作20 min后,激光器温度控制在25℃,满足激光器正常工作要求。根据激光器及建立的温控方法,开展高低温环境下激光器工作能力实验研究,采集实验过程中的激光器温度数据,测量高低温条件下激光输出能力。实验结果表明:实测激光器温度与有限元仿真温度数据基本吻合,两者误差小于10%;采用所提出的温控方法,激光器在高低温条件下可以正常工作,输出功率与室温条件下一致。

Airborne lidar is an important means to achieve long-range accurate atmospheric monitoring.Its laser wavelength is consistent with the absorption spectrum of most atmospheric pollutants and chemical substances,which makes it an important laser source for airborne lidar.However,it is difficult to design a temperature control system for airborne CO_(2) lasers to work in the−40°C−55°C temperature range under the controlled volume and weight conditions.In this paper,we propose a temperature closed-loop control meth-od,in which the laser characteristic and environment temperature are used as input,and a thermo electric cooler and forced air cooling are combined.According to the structure and heat transfer characteristics of the laser,the thermo-electric cooler and the level of forced air cooling,the finite element model of temperature control method is established to optimize the temperature control performance of the laser.In a high temper-ature environment of 55°C,the temperature of the laser is controlled at 40°C after the temperature control system operates for 25 min.In a low temperature environment of−40°C,the laser temperature is controlled at 25°C after the temperature control system operates for 20 minutes,which meets the normal working re-quirements of the laser.According to the laser and the established temperature control method,the experi-mental research on the working ability of the laser in high and low temperature environment is carried out,the temperature data of the laser in the experimental process is collected,and the laser output power is meas-ured under high and low temperature conditions.The experimental results show that the experimental meas-ured temperature data is consistent with the finite element simulation results and the error between them is less than 10%.The laser using the proposed temperature control method can work steadily,and the output power of the laser is consistent with that of the laser at room temperature.