自由空间光通信是以激光作为信息载体,是一种不需要任何有线信道作为传输媒介的通信方式。它结合了微波通信和光纤通信的优势,具有速率高、功耗低、机动性强等特点,在卫星通信、本地宽带接入和军事通信领域都具有极大的发展潜力。介绍了欧美发达国家在自由空间光通信方面的研究现状,并分析了它们的关键技术。指出了自由空间光通信的发展趋势。 Free space optical communication uses laser as the information carrier and is a communication method that does not require any wired channel as a transmission medium. It combines the advantages of microwave communication and optical fiber communication with high speed, low power consumption and high mobility. It has great potential for development in the fields of satellite communications, local broadband access and military communications. This paper introduces the research status of the developed countries in Europe and the United States in free space optical communications and analyzes their key technologies. Pointed out the development trend of free space optical communication.