Q-switched tunable fiber laser utilizing silver nanoparticles deposited onto PVA film as saturable absorber

We demonstrate a broadband-tunable Q-switched fiber laser by exploiting a silver nanoparticles (SNP) saturable absorber (SA) as a Q-switcher. The SA device was prepared by depositing SNP onto a polyvinyl alcohol thin film utilizing an electron beam deposition technique. The SA was then incorporated into an erbium-doped fiber laser cavity to generate Q-switched pulses. By adjusting a tunable filter inside the laser cavity, the generated Q-switching pulses train operation could be tuned from 1535 to 1565 nm with the highest slope efficiency of 25.3% obtained at 1560 nm. At this operating wavelength, the laser repetition rate was raised from 15.1 to 28.4 kHz, whereas the pulse width shrunk from 19.45 to 11.85 μs with an increasing laser diode power from 14.9 to 37.8 mW. The pulse energy of 27.5 nJ was obtained at 37.8 mW pump power.