Dual-comb spectroscopy with two on-chip III-V-on-silicon 1-GHz mode-locked lasers

A dual-comb interferometer with two semiconductor lasers on silicon photonic chips enables an optical resolution of 1 GHz, over a 0.7-THz span. The spectrometer di- rectly and unambiguously samples near-infrared rovibrational transitions without spectral interleaving.