2-μm wavelength all-fiber Q-switched double-clad fiber laser using monopiece single-layer chemical-vapor-deposition graphene

Abstract

We demonstrate a large-energy 2-μm double-clad Tm-doped fiber laser (DC-TDFL) Q-switched by a monopiece single-layer graphene nanosheet. The single-layer graphene is fabricated by the chemical vapor deposition (CVD) method, and then transferred onto the facet of a fiber ferrule for constructing a fiber-compatible saturable absorber (SA). The Q-switching operation of the DC-TDFL at 1980 nm is achieved and has a large pulse energy of 1.06 μJ (corresponding to the average output power of 28.6 mW). The narrowest pulse duration is 2.7 μs, and the pulse repetition rate can be tuned from 8 to 27 kHz by changing the pump power from 2.35 to 2.82 W. To the best of our knowledge, this work is not only the first demonstration of a 2-μm Q-switched all-fiber laser using monopiece single-layer CVD graphene as a SA, but also generates the largest pulse energy from graphene-based all-fiber DC-TDFLs. © 2014 Society of Photo-Optical Instrumentation Engineers (SPIE) (DOI: 10.1117/1.OE.53.10 .106103)