We present an experimental study of optical frequency comb generation based on cascaded quadratic nonlinearities inside a continuous-wave-pumped optical parametric oscillator. We demonstrate comb states which produce narrow-linewidth intermode beat note signals, and we verify the mode-spacing uniformity of the comb at the Hertz level. We also show that the spectral quality of the comb can be improved by modulating the parametric gain at a frequency that corresponds to the comb mode spacing. We have reached a high average output power of over 4 W in the near-infrared region, at ~2µm.
|Journal||Physical Review A: Atomic, Molecular, and Optical Physics|
|Publication status||Published - 10 Sep 2015|
|MoE publication type||A1 Journal article-refereed|