Soliton picosecond pulse generation with a spin-coated PEDOT: PSS thin film

Organic materials have been widely explored in various of electronic and photonic applications. poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS) is one of the organic materials that exhibits excellent optical properties including wide operating bandwidth and fast relaxation time. These properties are important for fiber laser applications to induce ultrafast phenomenon. In this experiment, PEDOT: PSS thin film was successfully fabricated based on spin coating technology for use as a saturable absorber (SA) and it featured saturation intensity of 0.21 MW/cm2 and modulation depth of 22%. The incorporation of PEDOT: PSS SA into erbium-doped fiber laser cavity successfully induced a 1.74 ps mode-locked laser at wavelength of 1567.6 nm. The pulse energy and output power were achieved at about 2.79 nJ and 6.89 mW respectively. This is the first time that PEDOT: PSS is applied as a SA to generate a soliton mode-locked laser at wavelength of 1.55 μm.