摘要
为了优化以半导体激光器为光源的激光多普勒测速仪(LDV)的光路,基于半导体激光器的非对称结构,建立了参考光为像散椭圆高斯分布,信号光为圆形艾里分布的相干探测模型,理论分析了椭圆率、像散等参数对外差干涉效率和探测器接收的参考光功率的影响。结果表明,外差干涉效率和参考光功率均随椭圆率的增加而减少,并且外差干涉效率随像散的增加进一步降低,因此,半导体激光器的非对称结构会导致探测器输出减小,破坏系统信噪。在此基础上提出了双柱透镜系统对光束进行整形以降低半导体激光器的非对称结构对探测器输出的不利影响。
According to the asymmetrical structure of semiconductor laser, the model of coherent detection is established with the reference and signal beams are astigmatic elliptical Gaussian beam and round Airy beam, respectively. The effect of the ellipticityand astigmatism on the output of photodetector （PD） of Laser Doppler Velocimeter （LDV） is analyzed by considering the heterodyne efficiency and power of reference beam within the PD surface. The optimum PD radius r0 and the optimum ratio of spots radius k which can make the heterodyne efficiency maximum for each ellipticity b without considering the astigmatism are obtained. The results show that the heterodyne efficiency and output of PD decrease with the increase of b, leading to the reduction of the output of PD and the signal-to-noise ratio of LDV. To eliminate the influence of the ellipticity on the output of PD, the system of double cylindrical lenses to collimate the optical spot is put forward.
出处
《激光杂志》
北大核心
2016年第10期26-30,共5页
Laser Journal
关键词
激光多普勒测速仪
外差干涉效率
参考光功率
laser doppler velocimeter （LDV）
heterodyne efficiency
power of reference beam
