研究了一种光功率效率高的非对称限幅光正交频分复用(OFDM)调制技术,通过对信号的非对称削减,将OFDM调制技术运用到光通信领域。将这种非对称限幅光OFDM技术运用到大气激光通信系统中,分析了采用非对称限幅光OFDM技术大气激光通信系统在大气湍流信道下的性能。在此基础上,将低密度奇偶校验(LDPC)码和置信传播迭代译码算法应用到大气激光通信系统中,并结合非对称限幅光OFDM强度调制方案,在大气湍流信道中进行了仿真。仿真结果表明,LDPC码具有优越的纠错能力并获得了较大的编码增益,该方案可以满足大气激光通信系统的需要。 An asymmetric limiting optical Orthogonal Frequency Division Multiplexing (OFDM) modulation technique with high optical power and high efficiency is studied. The OFDM modulation technique is applied to the field of optical communication by asymmetrically reducing the signal. The asymmetric limiting optical OFDM technology is applied to atmospheric laser communication system, and the performance of atmospheric laser communication system using atmospheric asymmetric limiting optical OFDM technology under atmospheric turbulence channel is analyzed. Based on this, the low density parity check (LDPC) code and the belief propagation iterative decoding algorithm are applied to the atmospheric laser communication system, and combined with the asymmetric limiting optical OFDM intensity modulation scheme, the simulation is carried out in the atmospheric turbulence channel . Simulation results show that the LDPC code has superior error correction capability and greater coding gain, which can meet the needs of atmospheric laser communication system.