Sub-picosecond Graphene-based Harmonically Mode-Locked Fiber Laser With Repetition Rates up to 2.22 GHz

Abstract

Passive harmonic-mode locking (PHML) of erbium-doped fiber laser with multilayer graphene is presented. The laser could operate at several harmonics (from 2nd to 21st) of the fundamental repetition frequency of the ring resonator (106 MHz). The highest achieved repetition rate was 2.22 GHz (which corresponds to the 21st harmonic) with 900 fs pulse duration and 50 dB of the supermode noise suppression. The saturable absorber was formed by multilayer graphene, mechanically exfoliated from pure graphite block through Scotch-tape and deposited on the fiber ferrule.