Cross-phase modulation instability in mode-locked laser based on reduced graphene oxide

TL;DR

This paper reports the experimental observation of cross-phase modulation instability in a mode-locked fiber laser enhanced by reduced graphene oxide, demonstrating different phase matching conditions and sideband generation under varying polarization states.

Contribution

It introduces a novel fiber laser setup with reduced graphene oxide to enhance nonlinearity and study XPMI, revealing polarization-dependent phase matching and sideband characteristics.

Findings

XPMI observed in a fiber ring cavity with reduced graphene oxide.

Enhanced nonlinearity reduces the threshold for XPMI.

Different phase matching conditions in two polarization directions.

Abstract

Cross-phase modulation instability (XPMI) is experimentally observed in a fiber ring cavity with net normal dispersion and mode-locked by long fiber taper. The taper is deposited with reduced graphene oxide, which can decrease the threshold of XPMI due to the enhanced nonlinearity realized by 8 mm evanescent field interaction length and strong mode confinement. Experimental results indicate that the phase matching conditions in two polarization directions are different, and sidebands with different intensities are generated. This phase matching condition can be satisfied even the polarization state of the laser varies greatly under different pump strengths.