Hollow core photonic band gap infrared fibers

Abstract

This invention pertains to a hollow core photonic band gap chalcogenide optical glass fiber and to a fabrication method for making the fiber. The fiber, which is 80-1000 microns in outside diameter, is characterized by a solid glass circumferential region and a structured region disposed centrally within the solid region, the structured region includes a hollow core of 1 micron to several hundreds of microns in diameter surrounded by a plurality of parallel hollow capillaries extending parallel to the core, the core being centrally and longitudinally located within the fiber. Ratio of open space to glass in the structured region is 30-99%. The fabrication method includes the steps of providing a mold, placing chalcogenide micro-tubes around the mold, stacking chalcogenide micro-canes around the stacked micro-tubes, fusing the micro-tubes and the micro-canes to form a preform, removing the mold and drawing the preform to obtain the fiber. In an alternative fabrication method, the fiber is made by extruding flowing chalcogenide glass through suitably made plate to form a preform and then drawing the preform to form the fiber.

1 - 11 . (canceled)  
   
   
       12 . Fabrication method for a hollow core photonic band gap optical fiber comprising the steps of: 
 (a) providing a mold,    (b) placing chalcogenide micro-tubes around the mold,    (c) stacking chalcogenide micro-canes around said micro-tubes,    (d) fusing the micro-tubes and the micro-canes for form a preform,    (e) removing the mold, and    (f) drawing the preform to form the hollow core photonic band gap fiber having outside diameter of 80-1000 μm, hollow core of from 1 micron to hundreds of microns, a structured region to impart photonic band gap to the fiber aroung the hollow core formed of plurality of openings arraned in at least three courses around the core with each opening being 1-12 μm and arranged in a pattern to yield a photonic band gap, and a solid region 5-500 μm thick surrounding the microstructured region to provide structural integrity to the microstructured region.    
   
   
       13 . Method of  claim 12  wherein the micro-tubes have thickness of 50-200 μm, internal diameter of 500-2000 μm, and length of 2-100 cm; and micro-canes are solid with outside diameter of 600-2400 μm and length of 2-100 cm and the hollow core is circular 2-200 μm in diameter.  
   
   
       14 . Method of  claim 12  wherein the micro-tubes have thickness of 100-150 μm, and length of 5-20 cm; and the micro-canes are solid with outside diameter of 1000-2000 μm and length of 5-20 cm.  
   
   
       15 . Method of  claim 13  wherein the micro-tubes are disposed in a glass tube.  
   
   
       16 . Method of  claim 13  wherein said step of fusing is carried out in an inert atmosphere in the glass transition temperature.  
   
   
       17 . Method of  claim 12  wherein the chalcogenide glass in the micro-tubes and micro-canes has loss of 0.5 dB/m and lower.  
   
   
       18 . Method of making hollow core photonic band gap optical chalcogenide fiber comprising the steps of: 
 (a) extruding through a plate having a central opening, a region corresponding to a structured region with a plurality of openings arranged in a periodic pattern in at least three courses around the central opening, and a solid region around the region corresponding to the structured region to form a preform, and    (b) drawing the preform to obtain the fiber.    
   
   
       19 . Method of  claim 18  including the step of cooling the drawn fiber to room temperature.  
   
   
       20 . Method o  claim 18  including the step of heating chalcogenide glass having loss of 0.5 dB/m or lower to a temperature high enough to render it flowable.