中文摘要：

基于半导体激光器速率方程,采用贝塞尔函数推导激光器非线性互调失真表达式.在GammaGamma湍流信道下,针对无线光多路副载波二进制相移键控调制,研究非线性互调失真对系统载波互调噪声比及误码率性能的影响,并给出系统最佳调制指数的选取与非线性系数的对应关系.结果表明,同一湍流条件下,调制指数小于最佳取值时,随着调制指数增加载波互调噪声比上升、误码率下降,而调制指数高于最佳取值时系统性能劣化.当闪烁指数为0.2,最佳调制指数为0.6时,获得的最大载波互调噪声比为12.9dB.

英文摘要：

Based on the rate equation of semiconductor laser,the expression of laser nonlinear intermodulation distortion was deduced by Bessel function.According to the Gamma-Gamma model under the turbulence channel,the influence of performance about carrier signal to intermodulation distortion and noise ratio and bit error rate was researched based multiple subcarrier binary phase shift keying modulation.The selection of optimal modulation index with the corresponding relation of nonlinear coefficient was given.The results show that under the same turbulence condition,carrier signal to intermodulation distortion and noise ratio increases and bit error rate decreases with the increasing of modulation index when the value of modulation index is less than the optimum index.However,when the value of modulation index is bigger the best index,system performance deteriorates. When the scintillation index is 0.2and the optimum modulation index is 0.6,the maximum carrier signal to intermodulation distortion and noise ratio can get to 12.9dB.