Mid IR Holmium, Praseodymium - doped Fluoride Fiber Laser Pulse Operation

Pulsed operation of a novel single-clad mid IR Ho3+, Pr3+ co-doped ZBLAN fiber laser ‎excited by a Nd:YAG laser at 1064 nm has been demonstrated using pulse-pumping. An acousto-optic modulator (AOM) has been used to modulate the CW input pump ‎laser and used in either zero-order or first-order operation. A regular output train of pulses was generated for modulation frequencies over 1 Hz - 100 kHz ‎with zero-order operation of the AOM. A maximum peak power of ~ 50 W and pulse ‎duration of ~200 ns have been obtained for a modulation frequency of 45 kHz and 9.3 ‎W pump power. Single-end and double-end pumping of the ‎first-order AOM operation for the fiber have also been demonstrated to avoid the overheating of the modulator which ‎reduces the modulation efficiency. The same results as the zero AOM operation were obtained when the fiber laser was pumped with a pumping power of about 5 watts. Keywords: Fiber lasers, Pump pulsed operation, Acousto-optic modulator (AOM), Single-end and double-end pumping. PACs: Fiber lasers, 42.55.Wd, Acousto-optical devices, 42.79.Jq.