title: Mid-infrared supercontinuum generation based on cascaded Raman scattering in a few-mode As2S3fiber pumped by a thulium-doped fiber laser.
abstract: By pumping a 1.7-m-long As2S3fiber at 2050 nm directly, a fiber-based mid-infrared supercontinuum (SC) source with an output power of 366 mW is demonstrated. This is the first experimental demonstration to obtain such a mid-infrared SC in a piece of chalcogenide fiber pumped at 2 μm directly. The cut-off wavelength of the As2S3fiber is 3.5 μm, indicating that it could support several modes at around 2 μm. It is found that nonlinear spectral broadening mechanisms in the few-mode chalcogenide fiber could be affected through adjusting the butt-coupling position. That is because different positions will excite different modes that correspondingly possess different nonlinearity and dispersion characteristics. When stimulated Raman scattering (SRS) corresponding to the excitation of the fundamental mode becomes dominant in this few-mode fiber, an efficient cascaded SRS-based SC is obtained with five Stokes peaks ranging from 2 μm to 3.4 μm. Results from numerical simulation are in accord with the experimental results, showing that it is feasible to obtain an SRS based mid-infrared SC in a step-index As2S3fiber by using a 2 μm high peak power picosecond laser to pump directly.
authors.forename: Jinmei
authors.initials: J
authors.lastname: Yao
authors.forename: Bin
authors.initials: B
authors.lastname: Zhang
authors.forename: Ke
authors.initials: K
authors.lastname: Yin
authors.forename: Linyong
authors.initials: L
authors.lastname: Yang
authors.forename: Jing
authors.initials: J
authors.lastname: Hou
authors.forename: Qisheng
authors.initials: Q
authors.lastname: Lu