Broadband GaSb Saturable Absorber for Pulse Generation from C-band to Mid-Infrared

Material with nonlinear response to light intensity, i.e., the saturable absorber, is an important mean to realize pulsed lasers which have wide applications in many fields. In this paper, we report a broadband optical-intensity modulator, magnetron-sputtered GaSb thin film, for pulse generation from C-band to mid-infrared regions. By the virtue of GaSb thin film, soliton pulses with 308 fs/585 fs pulse width and 17.82 mW/64.69 mW output power were obtained at 1559 nm/1902 nm in an Er-doped fiber laser (EDFL) and a Tm-doped fiber laser (TDFL) respectively. Furthermore, GaSb thin film coated on a gold mirror was successfully used to achieve 2783 nm Q switching operation of a Er3+:ZBLAN fiber laser with a maximum output power of 420 mW. With such a wide operation wavelength range, GaSb thin film is of great potential for many nonlinear optical applications.