基于点阵照明的APD阵列外差激光雷达外差效率的提高

当前研制的快速成像无扫描激光雷达系统由于激光器功率和信号损耗的限制,遇到了无法增大作用距离的瓶颈。结合光外差体制和APD阵列探测器设计的APD阵列外差探测激光雷达系统可以有效地解决这个问题。鉴于光学系统的外差效率能够直接影响外差激光雷达的性能,因此照明方式的设计是该套激光雷达系统的一个关键。经过分析,传统的直接扩束照明模式下系统的平均外差效率仅为10-5量级,远无法打到使用要求;因此提出了采用改进的点阵照明,并采用在阵列探测器前置微透镜阵列实现匹配接收的方式来解决这一问题。计算结果显示,经过优化后的点阵照明模式下的系统外差效率可达0.82,进而证明了采用点阵照明设计的APD阵列外差激光雷达系统的性能可以达到实用要求,为进一步开展APD阵列外差激光雷达的研究工作奠定了理论基础。

Enhancement of heterodyne efficiency of heterodyne LADAR system with APD array detector based on array lighting

At the moment non-scanned imaging LADAR system whose advantage is rapidly imaging cannot work beyond a relatively short operating distance due to the restriction of laser power and attenuation of the signal. Therefore designing a new-type non-scanned heterodyne LADAR system with APD array detector is a imperative solution to this problem. The design of lighting systems is the concentration since different heterodyne efficiencies correspond to different optical systems and then decide the performance of the LADAR system directly. In this paper, it was discussed that the heterodyne efficiency of the system using a single expanded oscillator laser beam lighting system with a single collector lens stays only at 10-5 level which is far away from practical applications. Then, as a improvement design, array lighting theory was adopted with a micro lens array collector device played before the detector array, the maximum heterodyne efficiency of which reached 0.82 by calculation. The conclusion drawn in this paper proves the feasibility of array lighting heterodyne LADAR system theoretically and form the foundation for further research on heterodyne LADAR system with APD array detector.