Gain-switched 2.8μm Er3+-doped double-clad ZBLAN fiber laser

A pulsed Er 3+ -doped ZBLAN fiber laser at 2.8 μm in fundamental-transverse-mode operation is reported. Stable gainswitching is achieved with the repetition rate range from 0.5 to 10 kHz. The maximum laser pulse energy of up to 4.2 μJ and pulse duration of 1.18 μs at a repetition rate of 10 kHz, yielding the maximum peak power of 3.5 W, has been obtained. The maximum slope efficiency with respect to the launched pump power at 975 nm is determined to be 12.2%. Pulse spikes occur by increasing the pump energy of larger than 75 μJ.