Journal ArticleVisible-to-mid-IR tunable frequency comb in nanophotonicsRoy, Arkadev; Ledezma, Luis; Costa, Luis; Gray, Robert; Sekine, Ryoto; Guo, Qiushi; Liu, Mingchen; Briggs, Ryan M.; Marandi, Alireza<title>Abstract</title> <p>Optical frequency comb is an enabling technology for a multitude of applications from metrology to ranging and communications. The tremendous progress in sources of optical frequency combs has mostly been centered around the near-infrared spectral region, while many applications demand sources in the visible and mid-infrared, which have so far been challenging to achieve, especially in nanophotonics. Here, we report widely tunable frequency comb generation using optical parametric oscillators in lithium niobate nanophotonics. We demonstrate sub-picosecond frequency combs tunable beyond an octave extending from 1.5 up to 3.3 μm with femtojoule-level thresholds on a single chip. We utilize the up-conversion of the infrared combs to generate visible frequency combs reaching 620 nm on the same chip. The ultra-broadband tunability and visible-to-mid-infrared spectral coverage of our source highlight a practical and universal path for the realization of efficient frequency comb sources in nanophotonics, overcoming their spectral sparsity.</p>Springer Nature2023-12-0110494923Nature Communications1412041-1723https://doi.org/10.1038/s41467-023-42289-01918549; 1846273National Science Foundation