“…The advent of the optical frequency comb (OFC) bring a revolutionary breakthrough in precision optical frequency metrology by providing a direct and simple link between optical oscillation and microwave frequencies [1], [2]. Their ability to convert between optical and microwave frequencies as well as their broad spectral bandwidth [3] and high accuracy characteristics [4] make OFCs powerful tools in the fields of low-phase-noise microwave generation [5], [6], comb-based spectroscopy [7], [8], high-precision laser detection and ranging [9], [10], and atomic clock networks [11], [12]. With the rapid growth in these applications, portable, robust, low-power-consumption, and inexpensive OFCs are increasingly necessary.…”