Tunable Q-switched ytterbium-doped fibre laser by using zinc oxide as saturable absorber

This paper demonstrates the use of a zinc oxide (ZnO) thin film in a 1-μm ring laser cavity as a saturable absorber to successfully generate Q-switching pulses. The tunability of the laser pulses is achieved by integrating a tunable bandpass filter (TBPF) in an ytterbium-doped laser cavity that results in 9.4 nm of tuning range, which wavelength is from 1040.70 nm to 1050.1 nm. The peak energy in the pulse which is 1.47 nJ was measured together with a minimum pulse width of 2.4 μs. In addition, the repetition rate increases from 25.77 to 45.94 kHz as the pump power level being increased from 103.1 to 175.1 mW. The results obtained in this experiment demonstrated consistent results and stable throughout the experiment. Therefore, ZnO thin film is considered as a good candidate in 1-μm pulsed laser applications.