Fiber fuse in chalcogenide photonic crystal fibers.

We observe fiber fuse in tapered GeAsSe photonic crystal fibers (PCF) at around 7  MW/cm of intra-core intensity. Vertically cleaved facets from the un-tapered regions and the tapered regions were imaged. The images show shallow voids of different shapes confined to the fiber core. After longitudinally polishing a segment of the PCF, we imaged the PCF internal structure's top view, revealing the fuse voids' geometries and periodicity. In addition, fiber fuse was terminated in one PCF sample by a fast laser shutdown, hence saving a small segment from catastrophic damage. Four-wave-mixing was performed on this transmissive segment to estimate the dispersion. The results yielded an evident hole-pitch ratio change after fiber fuse. To our knowledge, this is the first report of fiber fuse on non-silica glass fibers and the first study of its aftermath on this un-destroyed segment of PCFs.