A novel technique for the fabrication of a saturable absorber for fiber lasers: pulsed laser deposition

Abstract In the present work, for the first time, it is demonstrated that a zinc oxide (ZnO) thin film deposited directly on a fiber ferrule using a pulsed laser deposition (PLD) is a novel technique to prepare a saturable absorber (SA) for doped fiber lasers. The erbium-doped fiber laser based on this SA and erbium-doped fiber as a gain medium yields optical pulses with emission wavelength 1567.86 nm at a 3 dB spectral bandwidth of 1.24 nm at 42 mW. As the pump power is increased, the pulse duration decreases from 23.58 µ s to 5.6 µ s, and the pulse repetition rates increase from 10.79 kHz to 70.78 kHz. A maximum peak power, pulse energy and average output power of about 9.4 mW, 65.8 nJ, and 4.6 mW, respectively, have been achieved at a maximum pump power of 368 mW. The long-term stability and the damage threshold of the SA are also discussed. These findings suggest that the PLD technique is a promising technique to fabricate a cost-effective and stable SA for the fabrication of passively Q-switched fiber lasers.