Method for Producing Core/Clad Glass Optical Fiber Preforms Using Hot Isostatic Pressing
Patent, Filed 28 Jun 96, patented 7 Apr 98
DEPARTMENT OF THE NAVY WASHINGTON DC
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Coreclad glass optical fiber preforms free of bubbles and soot at the coreclad interface are fabricated by inserting a glass core rod into a cladding glass tube sized so that space remains between them, sealing the top and bottom of the tube onto the core rod to form a seated space between them which is relatively soot free and under a vacuum and then hot isostatically pressing the seated composite to collapse the tube onto the rod and also collapse bubbles In the glass. Soot formation is avoided or minimized by purging the space with inert gas while the bottom of the tube is collapsed onto the rod and by seating the top under a dynamic vacuum and at the lowest possible temperature to avoid soot formation without cracking the glass. The space is vacuum outgassed before the second seal is made. Chalcogenide fiber drawn from a preform made in this fashion exhibits very low transmission losses.
- Fiber Optics and Integrated Optics