Coherent Beam Combining of Very High Power Optical Amplifiers for Optical Feeder Links

Free space optical (FSO) links are considered as an essential part of future satellite communications as they benefit from wide optical bands, absence of frequency regulation, and synergy with terrestrial networks [1], [2]. Nevertheless, several challenges remain for enabling very high capacity optical links. For the optical feeder uplink, a major one is the generation of optical carriers strong enough to carry the communication signal from a ground station up to geostationary satellites. The output power of telecom optical amplifiers has been increased over the past decade, notably with the recent demonstration of very high power optical amplifier (VHPOA) capable of delivering up to 50 W [3]. However, the coherent beam combination (CBC) of several VHPOAs is a promising solution to meet the very demanding requirements of future optical ground-based terminals.