Octave-spanning frequency comb generation based on a dual-mode microcavity laser

Octave-spanning optical frequency comb(OFC)generation has achieved great breakthroughs and enabled significant applications in many fields,such as optical clocks and spectroscopy.Here,we demonstrate octave-spanning OFC generation with a repetition rate of tens of GHz via a four-wave mixing(FWM)effect seeded by a dual-mode microcavity laser for the first time,to our knowledge.A 120-m Brillouin nonlinear fiber loop is first utilized to generate wideband OFCs using the FWM effect.Subsequently,a time-domain optical pulse is shaped by appropriate optical filtering via fiber Bragg gratings.The high-repetition-rate pulse train is further boosted to 11 pJ through optimal optical amplification and dispersion compensation.Finally,an octave optical comb span-ning from 1100 to 2200 nm is successfully realized through the self-phase modulation effect and dispersion wave generation in a commercial nonlinear optical fiber.Using dual-mode microcavity lasers with different mode intervals,we achieve frequency combs with octave bandwidths and repetition rates of 29-65 GHz,and demon-strate the dual-mode lasing microcavity laser as an ideal seeding light source for octave-spanning OFC generation.