Nanosecond Hybrid Q-Switched Er-Doped Fiber Laser With WS2 Saturable Absorber

We demonstrate a stable hybrid Q-switched Er-doped fiber (EDF) laser with WS
₂
as the saturable absorber (SA). The SA device is obtained by depositing WS
₂
on a tapered fiber using the pulsed laser deposition method. The modulation depth of the SA is 8.0%, the nonsaturable loss is 30%, and the saturation intensity is 200 MW/cm
²
. By combining the saturable absorption of fiber-taper WS
₂
and the effect of nonlinear polarization rotation, the Q-switched EDF laser is achieved with a pulse duration of 443 ns and average power of 43 mW. The repetition rate can be adjustable among 235-365 KHz. To our best knowledge, both pulse duration and output power are the best results among Q-switched EDF lasers with transition mental dichalcogenide materials like SAs. These results indicate that the proposed hybrid Q-switched EDF laser performs better to achieve shorter pulses with higher power in the future.