Single-mode microstructured fibre for the mid-IR range

A single-mode microstructured fibre for the mid-IR region based on silver halide crystals is fabricated for the first time. It is shown theoretically and experimentally that the fibre is virtually single-mode at a wavelength of 10.27 μm and has optical losses equal to 2 dBm^-1. It is demonstrated that crystal microstructured fibres offer a number of advantages compared to common fibres made of silver halide crystals. A broad transparency window of these materials (2 – 20 μm) makes promising the use of these fibres in spectroscopy and in nonlinear fibre devices for the mid-IR region.