Broadband, Flat Frequency Comb Generated Using Pulse Shaping-Assisted Nonlinear Spectral Broadening

Abstract

In this letter, we demonstrate the nonlinear generation of a low noise, ultra-flat frequency comb covering the full C-band. The comb is generated using nonlinear spectral broadening on a mode-locked laser, assisted by adaptive pulse shaping. A linear pulse shaping element, which is dynamically controlled by an adaptive algorithm exploiting the covariance matrix adaptation evolution strategy, is placed prior to a nonlinear element. A 3-dB bandwidth of 35 nm is achieved, and the power variations about a central region of 30 nm are less than 1 dB.