针对空时编码技术在空间激光通信应用中受到的限制，提出了一种基于强度叠加编码的空间光多输入多输出(MIMO)通信算法，设计了算法中使用的码元光强码的编码和解码规则，分析了不同天线阵列组合下的系统信道容量，给出了最佳判决门限选择方法，并在此基础上计算了不同系统组成下的误码率。仿真计算表明，与单发单收系统相比，强度叠加编码的光MIMO系统在信道容量方面有1倍以上提升，而误码性能优势也在10 dB以上的信噪比条件下得到充分发挥。

Based on analyzing the restriction of space-time coding used in the free space optical communication, the intensity superposition code is propounded to increase the channel capacity of the optical multiple-input multiple-output (MIMO) system. The code/decode rules for the system are designed. The channel capacities of different system forms are analyzed. The decision thresholds are chosen, and the bit error rates (BERs) of different system forms are computed. The simulation result indicates that the channel capacity of this system is more than doubled channel capacity of the traditional system. And the BER falls very fast when the signal-to-noise ratio (SNR) is more than 10 dB.