A novel approach for drawing optical fibers from disparate core/clad glasses

We report a new idea, based on the Wollaston wire technique, which is to draw optical fibers of core and cladding glasses such that the fiber-drawing temperature is: (a) above the liquidus of the core glass yet (b) matches the normal fiber drawing viscosity of the cladding glass. Property compatibility of the disparate glasses is discussed with particular reference to making fibers with a fluorozirconate glass core and oxide glass cladding, but realization of such fiber has been unsuccessful, so far, because of the aggressive attack of molten halides upon most oxide glasses. A demonstration of the Wollaston wire method involving fabrication of multimode fiber with a lead berate glass con and a Pyrex optical cladding is described. In addition, forming the oxide tube for the optical preform via extrusion is discussed.