Broadband mid-infrared supercontinuum generation in 1-meter-long As₂S₃-based fiber with ultra-large core diameter

In this study, the supercontinuum (SC) generation in a 1-m-long As₂S₃ fiber with a 200 μm core diameter was demonstrated experimentally. The high-purity As₂S₃ fiber we used exhibited very low optical loss with a background loss of approximately 0.1 dB/m at a wavelength of 2-5 μm. SC generation was studied by pumping the fiber at different wavelengths and different peak powers. A strong spectral broadening with a 30 dB spectral flatness spanning from 1.4 to 7.0 μm was obtained when the fiber was pumped with 150 fs short pulses at 5.0 μm. The SC generation in bent fiber was also studied. The result showed that the bending radius of the fiber will significantly affect the SC spectra bandwidth and the output power. The SC spectra in the used fiber could still be maintained when it was bent to a radius of 5 cm.