Sb_2Te_3-deposited D-shaped fiber as a saturable absorber for mode-locked Yb-doped fiber lasers

Abstract

We present a study on a antimony telluride (Sb2Te3)-deposited side-polished fiber device as a saturable absorber for Yb-doped mode-locked fiber lasers. Thin layers of Sb2Te3 with variable length were deposited by a pulsed magnetron sputtering technique. We demonstrate measured characteristics of the device and show that it can be treated as a hybrid component - tunable polarizer with saturable absorption properties. The polarizing extinction ratio varies from 1.5 dB up to 17.1 dB with increasing length of the deposition. The fiber components were employed in all-normal Yb-doped fiber cavities. All devices enabled for mode-locked operation by means of hybrid mode-locking or nonlinear polarization evolution mechanism. In particular, the laser with 2 mm long Sb2Te3 absorber emitted 5.9 ps pulses with 4 mW of average output power.