Small-core chalcogenide microstructured fibers for the infrared

We report several small-core chalcogenide microstructured fibers fabricated by the 'Stack and Draw' technique from Ge15Sb20S65 glass with regular profiles. Mode field diameters and losses have been measured at 1.55 μm. For one of the presented fibers, the pitch is 2.5 μm, three times smaller than that already obtained in our previous work, and the corresponding mode field diameter is now as small as 3.5 μm. This fiber, obtained using a two step 'Stack and Draw' technique, is single-mode at 1.55 μm from a practical point of view. We also report the first measurement of the attenuation between 1 and 3.5 μm of a chalcogenide microstructured fiber. Experimental data concerning fiber attenuation and mode field diameter are compared with calculations. Finally, the origin of fiber attenuation and the nonlinearity of the fibers are discussed