Feasibility study of coherent LEO-ground link system using an optical injection phase lock loop technique

The feasibility of an optical injection phase lock loop technique for use in a coherent laser communications link between a LEO (Low Earth Orbit Satellite) and a OGS (Optical Ground Station) is studied. The Doppler frequency shift in the LEO-OGS coherent link is estimated and the impact on the link performance is investigated. It is demonstrated experimentally that a 10 Gbps BPSK link can successfully maintain stable frequency and phase locking status under the condition that the signal laser frequency changes over 9 GHz at a frequency deviation rate up to 1 Hz, which is ample to meet the requirement for the LEO-OGS coherent link. © 2011 IEEE.