Fluoride glasses are the only materials that transmit light in a continuous fashion from ultraviolet up to 8 μm in the mid-infrared
region, and can be drawn into high quality optical fibers. In fact fluoride glass fiber technology is the second
most mature, beside silica based fiber technology.
Fluoride glasses have experienced extraordinary development for more than 25 years. This development was motivated
in the beginning by their outstanding optical properties, especially the minimum theoretical attenuation which is 0.01
dB/km between 2 and 3 μm.
High quality optical fibers are now commercially available, with attenuation ranging from 5 to 30 dB/km, and
mechanical strength ranging from 50 to 100 kpsi depending on fiber diameter.
The fluoride glass transmission window is from 0.25 μm to 8 μm without any absorption peaks, while the resulting fiber
transmission window can be from 0.3 μm to 4.5 μm for standard fiber and from 0.3 μm to 6 μm for the extended window
fiber.
In this paper we will present mechanical and optical properties of current fluoride glasses and fibers, as well as high
power transmission results.
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