Research On Retro-reflecting Modulation In Space Optical Communication System

In recent years,with the increasing development of free-space optical communication,a kind of space optical communication technology based on retro-reflective light modulation has emerged.It is a new form of free-space optical communication which includes two asymmetric terminals: active terminal and retro-reflected modulation terminal.The space optical communication based on retro-reflective light modulation has many advantages,including large reception field,light weight,easy installation and low power consumption.It is especially suitable for the application in small work platform.The difference between the traditional free-space optical communication system and the retro-reflecting modulation space optical communication system is that the latter eliminates the sophisticated APT(Acquisition Pointing and Tracking)system.This form of communication will have a good application prospect in future military communications,star-ground links and air-ground links.Based on the traditional free-space optical communication system,the paper introduced the background and significance of the retro-reflecting modulation optical communication system first.Then,we discussed the working process and composition of the retro-reflecting modulation optical communication system in detail,and analyzed the main factors that affect the system.According to the analysis of the active terminal components,we selected suitable devices for the system,and designed the amplifying circuit of the receiver.In addition,we analyzed the working principle and characteristics of the multiple quantum well electro-absorption modulator in retro-reflected modulation terminal,and designed the driving circuit of the modulator in the communication system.Finally,2 kHz and 4kHz pseudo-random code was respectively used to test the optical communication link of cat's eye retro-reflecting light modulation,and the result shows that the communication rate of 1km is up to 300 kbps.