中文摘要：

利用光的轨道角动量传递信息可有效提高信息传输的速率。介绍了光轨道角动量的基本概念和主要特性,探讨了基于轨道角动量的自由空间光通信的基本原理和典型系统,并对相关的关键技术进行了分析,在此基础上,对基于轨道角动量的自由空间光通信的应用前景和发展趋势作了展望。

英文摘要：

Using orbital angular momentum （OAM） of optics can effectively increase the rate of information transmission of optical communication system. The basic concepts and main characteristics of OAM are introduced; the basic principles and typical systems of the OAM-based free space optical communication are overviewed. In addition, the corresponding key techniques are analyzed. Based on the which, the potential applications and developing trends of the OAM- based free space optical communication are also forecasted.