Chalcogenide microporous fibers for linear and nonlinear applications in the mid-infrared.

A new type of microstructured fiber for mid-infrared light is introduced. The chalcogenide glass-based microporous fiber allows extensive dispersion engineering that enables design of flattened waveguide dispersion windows and multiple zero-dispersion points - either blue-shifted or red-shifted from the bulk material zero-dispersion point - including the spectral region of CO(2) laser lines approximately 10.6 microm. Supercontinuum simulations for a specific chalcogenide microporous fiber are performed that demonstrate the potential of the proposed microstructured fiber design to generate a broad continuum in the middle-infrared region using pulsed CO(2) laser as a pump. In addition, an analytical description of the Raman response function of chalcogenide As(2)Se(3) is provided, and a Raman time constant of 5.4 fs at the 1.54 microm pump is computed. What distinguishes the microporous fiber from the microwire, nanowire and other small solid-core designs is the prospect of extensive chromatic dispersion engineering combined with the low loss guidance created by the porosity, thus offering long interaction lengths in nonlinear media.