▎ 摘　　要

In this work, we report on the synthesis and characterization of a functionalized graphene modified by Ag based nanoparticles (Ag2S@Ag) and the applications as an optical modulator for pulsed laser generation at 1 mu m in the compact waveguide platform written by a femtosecond laser. The nonlinear optical response of the Ag2S@Ag nanoparticle modified graphene has been explored by the Z-scan technique, which exhibits an enhanced ultrafast saturable absorption response with higher modulation depth and lower saturation intensity. The Q-switching and Q-switched mode locking have been realized in a waveguide laser system by using Ag nanoparticle modified graphene as a saturable absorber (SA) mirror. Fundamental Q-switched mode-locked waveguide lasers with a repetition rate of 6.44 GHz have been achieved, reaching shorter pulse duration (33 ps) in comparison to that (52 ps) through unmodified graphene SA. This work suggests potential applications of functionalized graphene in ultrafast photonics. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement