Green, red and IR frequency comb line generation from single IR pump in AlN microring resonator

摘要

On-chip frequency comb generations enable compact broadband sources forspectroscopic sensing and precision spectroscopy. Recent microcomb studiesfocus on infrared spectral regime and have difficulty in accessing visibleregime. Here, we demonstrate comb-like visible frequency line generationthrough second, third harmonic, and sum frequency conversion of a Kerr combwithin a high Q aluminum nitride microring resonator pumped by a single telecomlaser. The strong power enhancement, in conjunction with the unique combinationof Pockels and Kerr optical nonlinearity of aluminum nitride, leads to cascadedfrequency conversions in the visible spectrum. High-resolution spectroscopicstudy of the visible frequency lines indicates matched free spectrum range overall the bands. This frequency doubling and tripling effect in a singlemicrocomb structure offers great potential for comb spectroscopy andself-referencing comb.