Bismuth (III) Telluride-Polyethylene Oxide as passive saturable absorber

In this paper, we investigate the generation of 1.55 μm Q-switched fiber laser with incorporating of Bismuth Telluride (Bi₂Te₃) embedded in Polythylene Oxide (PEO) as a saturable absorber (SA). The Bi₂Te₃/PEO SAs was prepared by mixing the Bi₂Te₃ powder into PEO solution under ultrasonication. Then, Bi₂Te₃-PEO suspension was poured into a petri dish and left dry to develop free standing SA. The Q-switched laser operates at a central wavelength of 1531.6 nm with 3 dB bandwidth of 0.4 nm. By increasing the pump power, the repetition rate increased from 22.79 kHz to 65.27 kHz and with the decreased of pulse width from 18.12 μs to 7.12 μs. The signal to noise ratio at maximum pump power is estimated 68.2 dB, indicating that this SA can produce a highly stable Q-switched pulsed laser.