Microwave Frequency Generation Using a Non-Octave-Spanning Optical Frequency Comb

Self-frequency stabilization of the repetition rate of an optical frequency comb using a short-path-length interferometer can be used to generate ultra-low phase noise microwaves. Moreover, this technique is compatible is photonic integration, indicating a pathway towards a chip-scale low-phase-noise microwave frequency source. Separately, difference-frequency stabilization allows ultra-low phase noise microwave generation without carrier-envelope phase locking. In this work, we evaluate the challenges in implementing a difference-frequency stabilization scheme with a short-path-length-interferometer. We find that the combination of a short-path-length and lower frequency multiplication factor will exacerbate electronic noise contributions, influence the ability of the feedback loop to achieve lock. We also find that dispersion management is essential to generating usable error signals for single-mode fiber delay lines that are longer than approximately 4 m.