Iron pyrite absorber for ultrashort pulse generation

We demonstrate a passively mode-locked pulse generation in an all-fiber erbium-doped fiber laser (EDFL) ring cavity using an iron pyrite (FeS2) based saturable absorber (SA) for the first time. The laser generates a stable soliton pulse operating at a central wavelength of 1562.4 nm when the 980 nm pump power was set within 125.23 mW to 166.4 mW. At a maximum output power of 166.4 mW, the mode-locked operation has a pulse width of 3.01 ps, a constant pulse train of 1.8 MHz, an average output power of 10.65 mW, and a pulse energy of 5.69 nJ. The fundamental frequency of the laser has a signal-to-noise ratio (SNR) of 65.2 dB, indicating the stability of the soliton pulse. This work supports the use of FeS2 as a saturable absorber that can motivate further academic exploration of two-dimensional (2D) material in nonlinear optics as well as in ultrafast photonics applications.