圆偏振调制激光通信系统设计

为了降低大气湍流和通信终端相对运动对通信系统性能造成的影响,对采用了圆偏振调制原理的通信系统进行了研究。激光的圆偏振特性在大气传输中变化很小,且圆偏振光具有旋转对称性,系统的性能不受两通信终端相对运动的影响,降低了技术的实现难度,具有很高的可靠性,特别适用于移动通信终端。介绍了两种圆偏振调制方式,推导了线偏振态与圆偏振态之间的转换过程,为圆偏振编码解码提供理论基础。针对这两种调制方式,提出了具体的实现方案,并设计出了圆偏振调制激光通信系统,在该系统中可验证两种编码方式,且结构简单、实现方便,可作为星载通信终端。并进行了简单的圆偏振编码通信实验,实现了数据发射和接收,证明了圆偏振调制的可行性。

Design of Laser Communication System with Circular Polarization Modulation

In order to reduce the impact of atmosphere disturbance and communication terminal relative motion to the performance of communication system,the circular polarization modulation is adopted.The circular polarization modulation has high reliability since the polarization properties of laser change relatively small while propagating through the atmosphere.Because of the rotational symmetry of circular polarization,the system performance is unaffected by the relative motion of the two terminals,and is especially suitable for mobile communications terminal.Two kinds of circular polarization modulation method are introduced,i.e.,circular polarization shift keying(CPolSK) and circular polarization division multiplexing(CPolDM).The conversion process between the linear polarization and circular polarization provides a theoretical basis for the circular polarization encoding and decoding.In view of these two kinds of modulation modes,the implementation is put forward,and the laser communication system of circular polarization modulation is designed.Two modulation schemes can be verified in the same system.The laser communication system is very simple and convenient,which could be used in space borne communication terminal.The communication system is verified with simple experiments,completing the transmitting and receiving of data to prove the feasibility of circular polarization modulation.