Supermode noise suppression in an actively mode-locked fiber laser with pulse intensity feed-forward and a dual-drive MZM

Abstract

The supermode noise in an actively mode-locked fiber laser is suppressed for the first time by a so-called pulse-intensity-feed-forward technique. In this novel scheme, the optical pulse is firstly converted into an electronic signal, and then fed forward to a dual-drive Mach–Zehnder modulator (MZM), where the optical pulse is modulated by the reversed intensity profile of itself. In a 12.5 m long actively mode-locked fiber ring laser experiment, the resulting power limiting shows a stable 10 GHz optical pulse train with a supermode-suppression ratio larger than 81 dB. The phase noise and pulse-to-pulse timing jitter are below −141 dBc Hz−1 at 10 MHz and 22.1 fs, respectively. Compared with the conventional fiber-nonlinearity-based power limiting schemes, our proposal is compact and stable.