Femtosecond mode-locked 1.5 μm fiber laser based on PEDOT: PSS as saturable absorber

We have successfully demonstrated the soliton mode-locked pulse generation in a 77 m long erbium-doped fiber laser (EDFL) cavity using Poly(3,4-ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT: PSS) as a saturable absorber (SA). The prepared PEDOT:PSS SA film exhibits excellent optical characteristics with large saturable absorption of 40% and low saturation intensity of 0.17 MW/cm2, appropriate for the soliton mode-locking generation. The fundamentally mode-locked EDFL operates at 1568.55 nm central wavelength, 2.465 MHz repetition frequency, a 3.06 nm 3-dB bandwidth and 4.46 nJ highest pulse energy.