A tunable-wavelength Q-switched fiber laser based on organic metal 8-hydroxyquinoline chelate as a saturable absorber

This work demonstrates the potential of organic metal 8-hydroxyquinoline chelate, Znq2, as a thin film saturable absorber (SA) in a fiber laser cavity. The SA has a modulation depth and saturation intensity of 16.6 % and 95 MW/cm2, respectively. The Q-switched laser had a repetition rate increased from 45 -85 kHz, while the pulse width shortened from 6.6 -2.8 mu s as the pump power increased from 38 -198 mW. The laser has a high signal-to-noise ratio (SNR) of 57.4 dB at a central wavelength of 1560 nm. The laser produced a tunable-wavelength operation when a tunable bandpass filter was used in the cavity. The wavelength was continuously tuned between 1520 -1563 nm with a very stable performance.