Towards on-chip spectroscopy based on a single microresonator

Frequency comb generation in the mid-infrared (mid-IR)region is attractive recently. Here, we propose the Ge-on-Si microresonator for power-efficient frequency comb generation in the mid-IR. An octave-spanning comb can be obtained with power reduced to 190 mW. The robustness of the frequency comb generation with localized spectral loss is also analyzed. Based on the analysis, we propose a novel architecture of on-chip spectroscopy systems in the mid-IR.