Full Nonlinear Conversion of Broadband Frequency Combs generated by Four-Wave Mixing in Highly Nonlinear Fibers

TL;DR

This paper demonstrates the generation of a broad 200-nm optical frequency comb at 1.5 microns using four-wave mixing in highly nonlinear fibers, and achieves full nonlinear conversion into its second harmonic with high power and spectral phase control.

Contribution

It introduces a method for full nonlinear conversion of broadband frequency combs generated by four-wave mixing in highly nonlinear fibers, including second harmonic generation without tilting the nonlinear crystal.

Findings

Generated a 200-nm bandwidth comb at 1.5 microns.

Achieved second harmonic conversion with high power.

Produced combs centered at 790-800 nm with 48 THz bandwidth.

Abstract

We generate a 200-nm optical frequency comb at 1.5 microns by injecting two single-frequency lasers into a highly nonlinear fiber, and explore its spectral phase properties and high power to demonstrate full nonlinear conversion into its second harmonic. Combs of optical frequencies with 100-nm (~ 48 THz) bandwidths, centered at 790-800 nm and spaced by 0.8-1 nm (380-470 GHz) were produced by second harmonic and multiple sum frequency generation simply by focusing into a 2-mm long nonlinear crystal. Conventional birefringence phase matching was used in normal incidence configuration without tilting the crystal.