Robust free-space optical frequency transfer in time-varying link distances conditions

Abstract

Future inter-satellite clock comparison on high orbit will require technology of optical time and frequency transmission between moving objects. Here we demonstrate robust optical frequency transfer in variable link distance conditions. This variable link is accomplished by the relative motion of a single telescope fixed on the experimental platform and a corner-cube reflector (CCR) installed on a sliding guide. Two acoustooptic modulators with different frequencies are used to separate forward and backward signals. With active phase noise suppression, we achieve an optimal frequency stability indoor of 1.9×10-16 at 1 s and 7.9×10-19 at 1000 s while the CCR is moving back and forth with a uniform velocity of 20 cm/s and acceleration and deceleration of 20 cm/s2. This work paves the way for future research on optical frequency transfer between ultra-high-orbit satellites.