Simultaneous Generation of Raman‐Assisted Soliton Microcombs and Tunable Multi‐Chromatic Raman Microlasers in Single Monolithic Thin‐Film Lithium Niobate Microrings

ABSTRACT High‐performance integrated broadband coherent light sources are essential for advanced applications in high‐bandwidth data processing and chip‐scale metrology, yet remain challenging. In this study, we demonstrate a monolithic Z‐cut lithium niobate on insulator (LNOI) microring platform that enables simultaneous generation of tunable multi‐chromatic microlasers and Raman‐assisted soliton microcombs. Exploiting the strong Raman activity and high second‐order nonlinearity of LNOI, we engineered a dispersion‐optimized microring with a loaded Q factor of 3.86 × 10 6 , facilitating on‐chip efficient broadband coherent light source. A novel phase‐matching configuration with all the waves of the same ordinary polarization was realized for the first time on this platform, feasibly enabling modal‐phase matched Raman‐quadratic nonlinear processes that extend lasing signals into the visible spectrum. Under continuous‐wave laser pumping at 3.73 mW in the telecom band, we achieved a Raman‐assisted soliton comb centered at 1624.49 nm with the record‐low pump threshold on the LNOI platform. Concurrently, multi‐chromatic Raman lasing outputs were observed at ∼1700, ∼813, and ∼535 nm within the same microring. The system exhibited efficient wavelength tuning of these multi‐chromatic laser signals through a 5 nm shift in pump wavelength. This work represents a significant advance in integrated photonics for versatile optical signal generation.