A Q-switched fiber laser using a Ti₂AlN-based saturable absorber

We experimentally demonstrate the fabrication of a polarization-insensitive Ti2AlN-based, fiberized saturable absorber (SA) for Q-switching of a fiber laser. The fabrication procedure for the SA is as follows. A mixture of Ti2AlN/polyvinyl alcohol (PVA) composite solution was deposited onto a slide glass and spread evenly. After the spread Ti2AlN/PVA composite dried, the formed film was stripped off the slide glass and transferred onto the flat end of a fiber connection/angled physical contact fiber ferrule. The modulation depth and saturation intensity of the resulting SA were measured to be ∼3.2% and ∼3.4 MW cm-2, respectively. The sandwich-structured SA was successfully used to generate Q-switched pulses from an erbium-doped-fiber ring cavity. The temporal width of the Q-switched pulses with a repetition rate of 41.55 kHz was 2.52 s at a wavelength 1557 nm.