Amiune, NicolásNicolásAmiuneFan, ZhiweiZhiweiFanPankratov, Vladislav V.Vladislav V.PankratovPuzyrev, Danila N.Danila N.PuzyrevSkryabin, Dmitry V.Dmitry V.SkryabinZawilski, KevinKevinZawilskiSchunemann, Peter G.Peter G.SchunemannBreunig, IngoIngoBreunig2023-01-232023-01-232023https://publica.fraunhofer.de/handle/publica/43424110.1364/OE.476436The potential of frequency comb spectroscopy has aroused great interest in generating mid-infrared frequency combs in the integrated photonic setting. However, despite remarkable progress in microresonators and quantum cascade lasers, the availability of suitable mid-IR comb sources remains scarce. Here, we generate mid-IR microcombs relying on cascaded three-wave-mixing for the first time. By pumping a CdSiP2 microresonator at 1.55 µm wavelength with a low power continuous wave laser, we generate χ(2) frequency combs at 3.1 µm wavelength, with a span of about 30 nm. We observe ordinary combs states with a line spacing of the free spectral range of the resonator, and combs where the sideband numbers around the pump and half-harmonic alternate, forming staggered patterns of spectral lines. Our scheme for mid-IR microcomb generation is compatible with integrated telecom lasers. Therefore, it has the potential to be used as a simple and fully integrated mid-IR comb source, relying on only one single material.enFrequency comb spectroscopyMicroresonatorsMid-infrared frequency combsCascaded three-wave-mixingjournal article