An ultralow-expansion (ULE) glass fiber developed by researchers at the Iowa State University (ISU) Center for Advanced Technology (Ames, IA) may improve the efficiency of laser delivery systems for surgical applications. In laser surgery, conventional silica glass fibers suffer from thermal and chemical degradation upon contact with tissue. Fragments fracture off the fiber tip, causing it to lose transmission capabilities and instead absorb beam energy.
Dr. Gerald Shirk of Full Spectrum Inc. (Ames, IA) worked with the ISU group to develop a more robust fiber. Led by Steve Martin, the ISU group chose ULE glass (Corning Glass Works, Corning, NY), a titanium oxide-doped silicon oxide that exhibits near-zero thermal expansion. In clinical use, the tips of ULE glass fibers remain intact and transmission capabilities are unaffected after contact with tissue.
To avoid absorption-causing reduction of the titanium oxide during the drawing process, the ISU researchers developed a technique for drawing the fiber in an oxidizing rather than an inert environment, says Full Spectrum director of materials development and former ISU post-doctoral researcher Abdelouahed Soufiane. The Food and Drug Administration has approved the ULE fiber for surgical use.
