The Study Of Retro Reflective Optical Transmission Channel

With the advancement of society,modern culture and economy are highly developed,and the services provided by today's communications are increasingly unable to meet people's daily needs.However,limited spectrum resources and scarce wireless communication bandwidth have limited communication development.At the same time,due to the advantages of large capacity,high rate,high efficiency and rich spectrum resources,free-space optical communication has attracted wide attention of scholars,and this technology can also be used as an effective measure to solve the above communication bottleneck problem.The retroreflective optical transmission system is the key technology in the field of free space optical communication research.A typical retroreflective optical transmission system is developed using a transceiver and a modulating retro-reflector that is a small,battery operating,and semi passive unit.These factors support the communication system to adapt to many harsh environment and limited load platforms.Based on the above advantages,the retroreflective optical transmission system has become a research hotspot in the field of optical communication.The main work and main research results are as follows:Firstly,this thesis briefly describes the research background and research status of free-space optical communication at home and abroad,and analyzes the research status and corresponding technical difficulties of the retroreflective optical transmission system.This thesis focuses on the design and channel characteristics of retroreflective optical transmission systems.Secondly,the corner cube reflector is an important reflection device of the retroreflective optical transmission system.In this thesis,the corner cube reflector model based on ray tracing technology is studied.The vector optical theory of refraction and reflection is used to derive the internal beam transmission process of the corner cube reflector.Through the additional phase analysis caused by the manufacturing deviation of the diagonal reflector and the study of the effective area change of the beam exiting from the bottom of the corner cube reflector caused by the different incident angles of the beam,a generalized theoretical model of the corner cube reflector is constructed.Then,the step-by-step optical transmission method is used to simulate the transmission process of the beam in atmospheric turbulence,and the random phase screen theory is used to record the optical field variation of the beam during transmission.Combined with the ray tracing technique of the corner cube reflector,this thesis constructs a theoretical model of the retroreflective optical transmission system by means of optical wave simulation.Through the numerical simulation analysis,the effects of the corner reflectors of different wavelengths and different materials,the oblique incidence of the beam and the manufacturing deviation on the retroreflective spot of the backward link are compared in the vacuum environment.The simulation results show that the effects of these factors can be ignored in atmospheric turbulence,the normalized light intensity of the two pass link fit well with the Gamma-Gamma(??)distribution curve,and the channel fading curve generated by the simulation has a high consistency with the theoretically calculated channel fading curve.Finally,the scheme of using the microarray instead of the corner reflector in the reflection terminal of the retroreflective optical transmission system is proposed.Through the optical wave simulation and indoor turbulence experiment,the pseudo-phase conjugate characteristics of the microarray are fully utilized to demonstrate the wavefront compensation effect of the microarray on atmospheric turbulence.The simulation and experimental results show that compared with the retroreflective light transmission system of a single corner reflector,the spot reflected by the microarray still converges at the transmitting receiver,and the indoor turbulence experiment results are consistent with the optical wave simulation results.