An optimized optical phase-locked loop with high bandwidth and stability for Raman laser generation

Abstract Among the existing techniques for Raman laser preparation, optical phase-locked loops (OPLLs) are widely used in quantum precision measurements due to their high regulation accuracy and low phase noise. Aiming at the problems of limited adjustment range and insufficient stability of the current OPLL, this paper designs an OPLL by optimizing the operating points with a bias voltage. Performance tests show that, the tuning range of the optimized OPLL is 2 GHz to 9 GHz. This wide frequency cover can produce Raman laser for both 87 Rb and 85 Rb atomic gravimeters. It can also be used to simplify the optical path in experiments to test the equivalence principle. The optimized OPLL has a long-term phase-locking capability. For integration times of 1 s and 1000 s, the relative Allan’s variance is 1.6 × 10 −11 and 5.2 × 10 −13 , respectively.