Silver-halide segmented cladding fibers for the middle infrared

There is a wide interest in single-mode optical fibers for the middle infrared range of 3-30 μm. These fibers +ill be useful for a variety of applications such as spatial filtering and interferometry. However, many technical and theoretical problems hindered the development of such fibers. Segmented cladding fibers may make it possible to combine an extremely large core area and single mode operation over a large spectral range. The design parameters may accurately control the optical properties of such fibers. We report here the design and fabrication of segmented cladding fibers made of crystalline silver halides, which are highly transparent in the middle infrared.