Reduction of impurities in fluoride glass fibers

• Published in: Journal of lightwave technology 1984-01, Vol.2 (5), p.587-592
• Main Authors: Mitachi, S., Terunuma, Y., Ohishi, Y., Takahashi, S.
• Format: Article
• Language: English
• Subjects: Applied sciences; Circuit properties; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; Glass; Impurities; Integrated optics. Optical fibers and wave guides; Optical and optoelectronic circuits; Optical fiber cables; Optical fiber losses; Optical fibers; Optical losses; Optical scattering; Propagation losses; Purification; Rayleigh scattering
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.1984.1073677

In order to realize a low-loss fluoride Optical fiber, impurity reduction is indispensable. The methods of recrystallization, extraction, chemical vapor-phase deposition, distillation, and sublimation were tried to purify the starting materials for a fluoride fiber. These purification methods were evaluated by measuring transmission loss of the fibers prepared by using the purified materials. It was found that recrystallization was useful for reducing impurities in ZrF 4 to the level of below 1 ppm. The extraction technique could be also applicable to purification of BaF 2 and GdF 3 . It was concluded that the sublimation was the most probable purification in order to prepare fluoride materials with less than 0.1-ppm impurities. As a result, a low-loss fiber with 8.5 dB/km at 2.12 μm was obtained by using the starting materials purified by sublimation.