LOW THRESHOLD AND HIGH PULSED ENERGY OF Q-SWITCHED ERBIUM DOPED FIBER LASER RESIDING BISMUTH (III) TELLURIDE EMBEDDED IN POLYVINYL ALCOHOL BASED SATURABLE ABSORBER

Abstract

In this paper, we present a Q-switched erbium doped fiber laser with Bismuth (III) Telluride used as a passive saturable absorber. The saturable absorber was fabricated by dissolving Bismuth (III) Telluride nano powder in polyvinyl alcohol suspension and dried in the ambient for three days. Then, the saturable absorber was cut and sandwiched in between two FC/PC fiber ferrules. The Q-switched operates at centre wavelength 1560 nm. The stable pulse operates at low threshold pump power at 18.31 mW. The laser repetition rate increased from 25.58 kHz to 48.69 kHz and pulse width decreased from 16.06 μs to 8.36 μs as the pump power tuned from 18.31 mW to 57.15 mW. A signal to noise ratio value of 43.62 dB matching with 25.58 kHz at pump power 18.31 mW. At the maximum pump power, the average output power is 5.20 mW with high pulse energy of 106.8 nJ