Red-diode-clad-pumped CW and mode-locked Er:ZBLAN fiber laser at 3.5 µm

We report on a red-diode-clad-pumped continuous-wave (CW) and mode-locked Er:ZBLAN fiber laser at 3.5 µm for the first time. Numerical simulation shows that a heavily-doped Er:ZBLAN fiber is favorable for effective generation of 3.5 µm laser through 658 nm laser diode pumping. Using a 7.0 mol.% Er:ZBLAN fiber, CW output power of 203 mW was experimentally obtained at 3462 nm. By incorporating a home-made semiconductor saturable absorber mirror into the cavity, diode-pumped CW mode-locked 3.5 µm Er:ZBLAN fiber laser was first demonstrated with an average power of 19 mW, a pulse duration of 18.1 ps, and a repetition rate of 46 MHz. The research results show that red-diode-clad-pumping provides a simple and potential scheme for 3.5 µm CW and mode-locked Er:ZBLAN fiber laser.