Tungsten tri-oxide (WO <sub/>3</sub> ) film absorber for generating Q-switched pulses in erbium laser

摘要： This paper reports a new type of passive saturable absorber (SA) made of transition metal oxide (TMO) embedded in polyvinyl alcohol (PVA). The Tungsten trioxide (WO3)-PVA SA is placed in an erbium-doped fibre laser cavity to produce Q-switched pulses operating at 1562.82 nm. The pulse laser starts to manifest at the threshold pump power of 40 mW and continues to exist until the maximum pump power of 195 mW. Within that pump power range, its pulse energy, repetition rate and pulse width vary from 98 to 142.85 nJ, 29.86 to 56.7 kHz and 5.032 to 1.85 μs, respectively. The pulse train is stable with a signal to noise ratio of 70 dB. This is the first demonstration of a Q-switched laser using such a SA.