Dual Micro‐comb Generation in Fiber Laser Driven by Single Ultra‐High‐Q Microfiber Resonator

Abstract Dual‐comb technology opens the route to a broad range of applications in science and engineering in past decades, and the progress in microresonator‐generated optical frequency combs (micro‐combs) has promoted the dual‐comb system to a new level of integration and high speed. However, the problem of self‐starting has yet been fully addressed for conventional external pumps, along with the high tape‐out cost and low fiber‐system‐compatibility for the core on‐chip resonators. Here a low‐cost all‐fiber dual‐comb source is demonstrated without an external pump by nesting one single microfiber resonator into a fiber laser cavity. The key resonator device features a record‐high Q‐factor of 10 7 in the microfiber scheme and an inherent structural birefringence, enabling a polarization‐multiplexed parametric process for dual‐comb generation. For the first time, the micro‐comb gets boosted in a microfiber resonator, and the typical super mode instability in the laser cavity comb is successfully suppressed. Our work highlights the ultra‐high‐Q microfiber resonator for a practicable and simply equipped alternative to generate micro‐combs for potential applications.