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

Abstract

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 spanning 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 demonstrate the dual-mode lasing microcavity laser as an ideal seeding light source for octave-spanning OFC generation.