Bulk α-alumina embedded tapered fiber as Q-switcher in an erbium-doped fiber laser

Abstract We present bulk α-alumina (Al2O3) in a polydimethylsiloxane matrix decorated tapered fiber with a modulation depth of 11%. The integration of α-Al2O3-saturable absorber (SA) in an erbium-doped fiber laser yielded a Q-switched operating regime within 62.0-308.6 mW pump power. The shortest pulse width was 7 μs, whereas the repetition rate was tunable from 19.17 to 43.24 kHz. This work reveals a substantial improvement over previously reported Al2O3-SA works with a recorded pulse energy of 150.32 nJ and an estimated damage threshold of beyond 6.75 GW/cm2 incident intensity. Our findings suggest that α-Al2O3-SA has enormous potential as a next generation light-absorbing material for high-energy photonic devices.