光空间调制(OSM)作为一种新型的光多输入多输出(OMIMO)技术，利用空间域激光器索引号额外携带信息，有效地提高了系统的传输速率和能量效率；同时，由于每符号周期仅激活一个激光器传递信息，较好地解决了传统OMIMO系统中的信道干扰和同步等问题。本文首先介绍了现有的几种光空间调制技术，概括和总结其在国内外的研究现状。此外，从传输速率、频谱效率、误码率(BER)和计算复杂度等四个方面对现有的OSM、光空移键控(OSSK)、增强型光空间调制(EOSM)和差分光空间调制(DOSM)等方案进行了比较分析。最后，指出了OSM 中亟需解决的关键性问题及其未来的发展方向。

Optical spatial modulation (OSM), a new optical multiple input multiple output (OMIMO) technique, effectively improves the transmission rate and energy efficiency by using the spatial domain laser index to carry additional information. Meantime, since only one laser is activated per symbol duration to transmit information, the problems of channel interference and synchronization are solved in traditional OMIMO system. This paper firstly introduces several OSM technologies and summarizes their research status both at home and abroad. Nextly, the OSM, optical space shift keying (OSSK), enhanced optical spatial modulation (EOSM) and differential optical spatial modulation (DOSM) schemes are compared and analyzed in terms of transmission rate, spectral efficiency, bit error rate (BER) and complexity. Finally, the key problems and future development direction are pointed out in OSM system.