Optical frequency synthesis with 1 Hz resolution

This paper reports on the development of a second generation coherent optical-to-microwave frequency chain based on the frequency-interval bisection method. We report successful operation of all three key elements of such a frequency chain: efficient nonlinear radiation production, reliable and accurate laser diode phase locking, as well as wide-span optical frequency comb generation. An analysis of the expected frequency stability of a synthesizer based on this type of frequency chain shows that it should be capable of transferring frequency stabilities at the level of 1.3×10^-15/τ