As the key terminal,the performance of PIN detector affects the stability and reliability of the optical satellite communication system.The properties of γ radiation and particle radiation of PIN detector under space radiation environment were researched.The results show that both radiation mechanisms impose effects on PIN detector,expressing as the increase of dark current noise and decrease of both responsivity and response bandwidth.It is indicated that the influence of space radiation on dark current noise should be the first factor to be considered in the design of optical satellite communication system.

To verify the potential space radiation-induced degradation of optical satellite communication system, the γ ray radiation experiments of its key components have been developed. No obvious performance degradations of the DFB laser and photo detector module were found at the total dose less than 150krad. The EDFA seems to be the most radiation sensitive, and it comes to its malfunction through the radiation of 16.2krad. It is believed that the high energy particles’ radiation effect should be first considered when it refers to the optical terminals’ applications in the space.

To improve the space anti-radiation performance of the optical satellite communication system,the research on the space radiation environment′s influence on system bit error ratio(BER)is carried out.The radiation-induced BER model is established,based on which the BER numerical calculations after the radiation damage of either optical source or optical detector are developed.The calculation results have proven that both γ radiation and proton radiation can degrade the system BER by several order of magnitude.It points out that some suitable radiation shielding measures or homodyne BPSK mode are needed.