2090 nm 200 W Peak Power 50 ns Pulsed PM Ho-Doped Fiber Amplifier Pumped at 1860 nm

We report the design and performance of a 2 μm dual-stage polarization maintaining (PM) holmium-doped fiber amplifier (HDFA) operating in either continuous-wave (CW) or pulsed regime. The amplifier is pumped at 1860 nm, which offers a better efficiency than a 1940 nm pump. In CW regime, we measured more than 1 W of output power at both 2051 nm and 2090 nm signal wavelengths. In pulsed mode, we tested the amplifier over a broad range of pulse widths (50-500 ns) and pulse repetition frequencies (PRFs) (50-1500 kHz). The PM HDFA delivered up to 200 W of peak power and 10 μJ of pulse energy with an excellent stability, while integrated inside a compact module.