Mid-infrared frequency comb generation via cascaded quadratic nonlinearities in quasi-phase-matched waveguides
Abstract
We experimentally demonstrate a simple configuration for mid-infrared (MIR) frequency comb generation in quasi-phase-matched lithium niobate waveguides using the cascaded- nonlinearity. With nanojoule-scale pulses from an Er:fiber laser, we observe octave-spanning supercontinuum in the near-infrared with dispersive-wave generation in the 2.5--3 m region and intra-pulse difference-frequency generation in the 4--5 m region. By engineering the quasi-phase-matched grating profiles, tunable, narrow-band MIR and broadband MIR spectra are both observed in this geometry. Finally, we perform numerical modeling using a nonlinear envelope equation, which shows good quantitative agreement with the experiment---and can be used to inform waveguide designs to tailor the MIR frequency combs. Our results identify a path to a simple single-branch approach to mid-infrared frequency comb generation in a compact platform using commercial Er:fiber technology.
Keywords
Cite
@article{arxiv.1801.07850,
title = {Mid-infrared frequency comb generation via cascaded quadratic nonlinearities in quasi-phase-matched waveguides},
author = {Abijith S. Kowligy and Alex Lind and Daniel D. Hickstein and David R. Carlson and Henry Timmers and Nima Nader and Flavio C. Cruz and Gabriel Ycas and Scott B. Papp and Scott A. Diddams},
journal= {arXiv preprint arXiv:1801.07850},
year = {2018}
}