Chalcogenide-glass polarization-maintaining photonic crystal fiber for mid-infrared supercontinuum generation

Abstract

In this paper, we report the design and fabrication of a highly birefringent polarization-maintaining photonic crystal fiber made from chalcogenide glass, and its application to linearly-polarized supercontinuum generation in the mid-infrared region. The fiber was drawn using the casting method from As38Se62 glass which features a transmission window from 2 to 10 μm and a high nonlinear index of 1.13 × 10–17 m2 W−1. It has a zero-dispersion wavelength (ZDW) at 4.56 μm for the fast axis and 4.68 μm for the slow axis and, at average ZDW, a large birefringence of 6.5 × 10–4 and consequently strong polarization maintaining properties are expected. Using this fiber, we experimentally demonstrate supercontinuum generation spanning from 3.1 to 6.02 μm and 3.33–5.78 μm using femtosecond pumping at 4 μm and 4.53 μm, respectively. We further investigate the supercontinuum bandwidth versus the input pump polarization angle and we show very good agreement with numerical simulations of the two-polarization model based on two coupled generalized nonlinear Schrödinger equations.