适用于高精度激光测距的光学系统设计

Design of optical system for high-precision laser ranging

随着激光雷达技术的发展和测距精度需求的提高,对发射和接收光学系统提出了新的要求,需具有光束可调节、测量光斑小、回波效率高等特性。设计一种工作于1550 nm光通信波段的收发一体光学系统,发射与接收模块共用部分光路,以减小接收视野盲区,同时有利于结构小型化。为解决不同测量距离、不同表面倾角造成的回波能量差异问题,将光学系统的扩束组件设计成放大倍率为2×~3.5×的连续可调结构;使用两组双胶合透镜进行色差校正,以降低光谱宽度对系统传播距离的影响。经设计优化,系统准直后的激光发散角小于0.3 mrad,出射光斑直径在6.26 mm~10.20 mm连续可调,对于50 m内的测量目标,照射光斑直径均小于20 mm,且在不同变焦位置发散角和光斑直径均满足设计要求。

With the development of laser radar technology and the improvement of ranging accuracy requirements,the new requirements are put forward for the transmitting and receiving optical system,which should have the characteristics of adjustable beam,small measurement spot and high echo efficiency.An transceiver integrated optical system working in the optical communication band of 1550 nm was designed.The transmitting and receiving modules share part of the optical paths to reduce the receiving blind area and facilitate the miniaturization of the structure.In order to solve the problem of echo energy difference caused by different measurement distances and different surface inclinations,the beam expansion components of the optical system were made into a continuously adjustable structure with the magnification of 2~3.5 times.The two sets of double gluing lenses were used for chromatic aberration correction to reduce the influence of spectral width on the system propagation distance.After design optimization,the laser divergence angle after system collimation is less than 0.3 mrad,and the diameter of the emergent light spot is continuously adjustable from 6.26 mm to 10.20 mm.For the measurement targets within 50 m,the diameter of the irradiation light spot is less than 20 mm,and the divergence angle as well as the light spot diameter meets the above requirements at different zoom positions.