Suitability of free space optical communication in military environments

Free Space Optical (FSO) communications use modulated collimated light energy, usually in the form of an infrared (IR) laser, to transmit data. This affords FSO many appealing qualities such as a very high bandwidth capability, a high level of security through a low probability of detection (LPD) and a low probability of intercept (LPI), and a signal that is impervious to radio frequency (RF) interference or regulation. Military communications require broadband capabilities at the highest level of security in an incredibly dense RF operating environment. The bandwidth and security qualities of FSO make it an attractive technology for military communications. However, a strict line of sight (LOS) requirement and link attenuation in poor atmospheric conditions limit its application. Several companies and groups are developing and implementing FSO communication solutions worldwide in response to a demand for broadband connectivity without RF interference at a relatively low price point. Recent advances in hybrid FSO-RF systems have improved performance in all atmospheric conditions. This paper presents taxonomy of the current state of FSO communications systems and analyzes the suitability of FSO as a military communication solution. The findings indicate further research, development, and link performance improvement is required before most implementation of FSO communications can occur.