Generation of Q-switched pulses on a graphene-silica hybrid waveguide

Abstract

The Q-switched laser sources on chip pave the way for the applications of laser processing, distance measurement and frequency conversion. In this work, using the monolayer graphene-silica hybrid waveguides with increased input optical power, Q-switched pulses with the pulse widths ranging from 1.57 μs to 5.06 μs and the repetition rates ranging from 47.23 kHz to 85.33 kHz are realized, which results in the maximum single pulse energy of 56.5 nJ. The interaction between graphene and propagation light in the waveguide is strengthened by coating the polymethyl methacrylate layer on the graphene-silica hybrid waveguide. The pump power threshold of Q-switching is reduced by a factor of 2.5, and the Q-switched pulses with pulse width of 1.21 μs is achieved. Besides, as the pump power increases, the Q-switched mode-locking pulses are also observed.