Active synchronization and modulation of fiber lasers with a graphene electro-optic modulator

Abstract

We report the synchronization of two actively <i>Q</i>-switched fiber lasers operating at 1.5 μm and 2 μm with a shared broadband graphene electro-optic modulator. Two graphene monolayer sheets separated with a high-<i>k</i><i>HfO</i>₂ dielectric layer are configured to enable broadband light modulation. The graphene electro-optic modulator is shared by two optical fiber laser cavities (i.e., an erbium-doped fiber laser cavity and a thulium/holmium-codoped fiber laser cavity) to actively <i>Q</i>-switch the two lasers, resulting in stable synchronized pulses at 1.5 μm and 2 μm with a repetition rate ranging from 46 kHz to 56 kHz.