Core-clad silver halide fibers with few modes and a broad transmission in the mid-infrared.

There is interest in single-mode fibers that are highly transparent in the mid-infrared. Such fibers would be valuable for spectroscopy, interferometry, and heterodyne detection. We have developed core-clad fibers made of crystalline silver halides with an external diameter of 900 microm and core diameters as small as 60 microm. These fibers exhibit homogeneous core and cladding regions, round cores, and smooth core-cladding interfaces. The 60 microm fibers support roughly 70 modes and have low losses over a broad spectral range in the mid-infrared. This will pave the road for the development of single-mode mid-infrared fibers. ie ty of America