Fabrication and properties of flexible chalcognide fiber image bundles

A high performance thermoplastic polymer, polyetherimide (PEI), which is thermally compatible with some chalcogenide glasses, is introduced as a cladding material to fabricate fiber image bundles. As₂S₃/PEI image bundles consisting of 900 fibers are fabricated through a stack and draw approach. The loss of the fibers, the dark fiber ratio, the resolution and crosstalk of the image bundles are characterized. The As₂S₃/PEI shows a good transmitting property in the 2 mm to 6 mm spectral region. The background loss is about 0.5 dB/m, and the peak loss at 4.0 μm due to S-H impurity absorption is about 3.5 dB/m. The fiber bundle containing 900 fibers with a diameter of 80 μm has a dark fiber ratio of 1%, exhibits a resolution of 7 line/mm and shows crosstalk of 1%. Clear infrared image of a soldering iron tip is obtained through this fiber bundle. The flexibility of the fiber bundles is achieved by dissolving the PEI into a solvent dimethylacetamide (DMAC). Flexible high-resolution chalcogenide fiber image bundles may be fabricated through the stack and draw approach using a thermoplastic polymer which can be dissolved into special solvents as an interlayer material similar to the 'acid-dissolved glass'.