Dual-Comb Generation in Monolithic High-Q Fiber Fabry-Perot Resonators

Dual-comb (DC) spectroscopy has revolutionized the field of metrology by enabling fast and accurate measurements using low-pass photodetectors [1]. This interferometric technique however requires high mutual coherence between the combs, for which various approaches have been developed, including electronic locking systems between the laser sources or generating the combs within monolithic laser systems [2]. In this work, we report the generation of DC sources within monolithic, high-quality-factor Kerr fiber Fabry-Perot (FFP) resonators by exploiting the spatial light multiplexing capabilities of these fiber systems. Additionally, these passive resonators offer seamless integration into photonic systems through standard FC/PC connectors with low insertion loss, making them practical for generating all-fiber optical frequency combs (OFCs) in the GHz range [3], [4].