Eliminating Crystals in Non-Oxide Optical Fiber Preforms and Optical Fibers
Dennis S. Tucker,
Michael R. LaPointe.
Non-oxide fiber optics such as heavy metal fluoride and chalcogenide glasses are extensively used in infrared
transmitting applications such as communication systems, chemical sensors, and laser fiber guides for cutting, welding
and medical surgery. The addition of rare earths such as erbium, enable these materials to be used as fiber laser and
amplifiers. Some of these glasses however are very susceptible to crystallization. Even small crystals can lead to light
scatter and a high attenuation coefficient, limiting their usefulness. Previously two research teams found that microgravity
suppressed crystallization in heavy metal fluoride glasses. Looking for a less expensive method to suppress crystallization,
ground based research was performed utilizing an axial magnetic field. The experiments revealed identical results to those
obtained via microgravity processing. This research then led to a patented process for eliminating crystals in optical fiber
preforms and the resulting optical fibers. In this paper, the microgravity results will be reviewed as well as patents and
papers related to the use of magnetic fields in various material and glass processing applications. Finally our patent to
eliminate crystals in non-oxide glasses utilizing a magnetic field will be detailed.
Keywords: Microgravity, magnetic field, non-oxide glass, crystallization
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