Octave-Spanning Supercontinuum Generation in As₂S₃-Silica Hybrid Waveguides Pumped by Thulium-Doped Fiber Laser

Abstract

Broadband supercontinuum sources are of interest for various applications. The near-infrared region (1-3 µm) is specifically useful for biomedical diagnostics. One of the promising medium for supercontinuum generation in the infrared region is the strongly guiding nonlinear waveguide with an arsenic trisulfide core (As 2 S 3 ) and a fused silica cladding. The geometrical and chemical properties of such a waveguide allow to finely tune the dispersion landscape and nonlinearity through the core diameter variations. Here we report the generation of octave-spanning supercontinuum in As 2 S 3 -silica hybrid nanospike waveguides pumped by a thulium-doped all-fiber femtosecond laser and amplifier system at 1.9 µm wavelength. The widest supercontinuum was obtained in the wavelength range from 1.1 to 2.5 µm (full width at -10 dB) in the waveguide with core diameter of 1.7 µm. Generation of significant dispersive waves as well as third harmonics component are observed. Numerical simulation shows that the generated supercontinua are coherent in the entire spectral range and can be exploited to create a self-referenced laser comb.

Numerical investigation of a wideband supercontinuum source based on a large-mode-area photonic crystal fiber pumped at 1.3 μm

“…In 2023, Van et al used a 1030 nm femtosecond laser to pump a water-filled-cladding PCF, obtaining a spectrum from 600 nm to 1750 nm [39]. In the same year, Voropaev et al used a thulium-doped all-fiber femtosecond laser and amplifier system to pump an As 2 S 3 -silica hybrid waveguide, obtaining a spectrum from 1100 nm to 2500 nm [40]. Relatively little work has been done on supercontinuum generation using silica based large mode area PCFs pumped at 1.3 µm.…”