Research On Craft Of Large Numerical Aperture Multiple-Composition Glass Flexible Fiber

The large numerical aperture optical fiber has realized the big field of vision and the wide angle observation in the observation system.Therefore,it has the widespread application demands in the military,the medicine,the industry domains,and so on.In order to enhance the numerical aperture value, this article increases the refractivity by enhancing the core glass refractive index.In the formula design,the lanthanum glass(B₂O₃-La₂O₃-BaO) took the basic composition of core glass,simultaneously introducing Nb₂O₅ to prepare the high refractive index of core glass.Through the research on the glass melt system and the craft system,we got core glass of refractive index 1.7 231 and expansion coefficient for 97×10^-7.Its performances matched with the cladding glass.In the optical fiber drawing craft,selecting the method of stick covered by pipe.Moreover,for preventing the core,the cladding glass difussing each other under the high temperature reduces the wiredrawing temperature as far as possible,and enhances the wiredrawing speed under the premise of wiredrawing craf smoothly.In addition,it introduced the hot melt manufacture craft of the multi-component optical fiber bundles,and has given the quite reasonable craft parameters.The drawing flexible optical fiber with matching the low refractive index cladding glass,its numerical aperture is 0.83 and the light accepting the angle is 124°.