激光告警接收机中多模光纤天线出射激光空间相干性研究

Research on Spatial Coherence of Laser from Multimode Fiber Optical Antenna in Laser Warning Receiver

傅里叶变换激光告警装置光学天线设计中,需要研究多模光纤出射光的空间相干性问题.在分析多模光纤中光场分布的基础上,建立了光纤作为二次光源的光源模型;运用经典的杨氏双缝实验和统计理论知识,分析了光纤出射光的空间相干性,推导出和空间相干性有密切关系的互强度;得出了多模光纤对输入激光空间相干性影响的数学表达式.结合实验论证了光纤芯径、数值孔径以及入射激光角度对传输激光空间相干性的影响.

In the design of optical antenna of Fourier transform laser warning receiver, the research on spatial coherence of laser from the multimode fiber optical antenna is important. A light source model regarding the fiber as a secondary source was established based on optical field distribution analysis. The laser spatial coherence from the fiber was analyzed by means of the Young＇s double-slit interference experiment and statistical theory. The mutual intensity of laser emitted from the fiber was deduced, and then the mathematical formula of spatial coherence was obtained. The experiments demonstrate the validity of the theoretical analysis