Patent ID: 9416042
Filing Date: 2016-08-16
CPC Classification: C03B,G02B

Claim Text:
1. A method making a hollow-core photonic band gap preform from a non-silica specialty glass, comprising the steps of: extruding the non-silica specialty glass to form a tube wherein the outer transverse shape of the tube is a hexagon, triangle, quadrilateral, or other polygon; stretching the tube to form a micro-tube with approximately the same outer transverse shape as the tube; stacking a plurality of micro-tubes into a bundle minimizing voids between adjacent micro-tubes and forming a central longitudinal void wherein the plurality of micro-tubes within the bundle comprise an inner structured region of the preform and the central void of the bundle comprises a hollow core in the preform; inserting the bundle into a jacket tube; and forming a consolidated preform by heating the jacketed bundle to the softening temperature of the non-silica specialty glass so the micro-tubes fuse to each other and to the jacket tube while maintaining the inner transverse shape of each micro-tube and of the core of the preform while reducing voids between adjacent micro-tubes and between the jacket tube and the micro-tubes.