Transition Metal Dichalcogenides (WS ₂ and MoS ₂ ) Saturable Absorbers for Mode-Locked Erbium-Doped Fiber Lasers

Abstract

We demonstrate an ultrafast fiber laser based on transition metal dichalcogenide materials which are tungsten disulfide (WS 2 ) and molybdenum disulfide (MoS 2 ) as saturable absorber (SA). These materials are fabricated via a simple drop-casting method. By employing WS 2 , we obtain a stable harmonic mode-locking at the threshold pump power of 184 mW, and the generated soliton pulse has 3.48 MHz of repetition rate. At the maximum pump power of 250 mW, we also obtain a small value of pulse duration, 2.43 ps with signal-to-noise ratio (SNR) of 57 dB. For MoS 2 SA, the pulse is generated at 105 mW pump power with repetition rate of 1.16 MHz. However, the pulse duration cannot be detected by the autocorrelator device as the pulse duration recorded is 468 ns, with the SNR value of 35 dB.