Status of ultralow loss glass fiber Available to Purchase

Within the last few years a search has begun for a glass suitable for transmitting light repeaterless for long distances. The anticipated optical transmission of the new ultralow loss material must be several times lower than that of silica glass (0.16 dB/km at 1.6 microns). Excitement over the actual achievement of ultralow has been fueled by the development of halide based glasses such as ZnCl2 and more recently the heavy metal fluorides which exhibit good transmission beyond 7.0 microns. Since the fundamental limitation to transmission is scattering, which has a dependence, these glasses suggest the possibility of very low loss at wavelengths greater than 2.0 microns. Now the fluoroberyllates, heavy metal oxides, and cha1cogenides are also being considered. It is apparent that SiO2 based glasses will not achieve much lower attenuation.