Luminescence Properties Of Bi~0 Doped Silica Optical Fiber

Bismuth-doped silica optical fiber realizes 1100-1600 nm near-infrared luminescence in the low-loss region,and it is an important material for ultra-bandwidth information transmission in the field of optical fiber communication.Although bismuth-doped silica optical fiber has a large bandwidth of near-infrared fluorescence,the center of luminescence cannot be completely clear,and the reaction mechanism with the intrinsic point defect remains unclear.In this paper,we theoretically study the relationship between interstitial Bi0 and near-infrared luminescence center in bismuth-doped silica optical fiber,and the reaction mechanism with four intrinsic point defects are revealed.This will help to improve the preparation technology and performance of bismuth-doped silica optical fiber,and provide an important theoretical basis for further realization of high-capacity,high-speed and long-distance optical fiber communication.The main research contents and results of this paper are as follows:(1)Construction and optimization of bismuth-doped silica optical fiber model.Silica optical fiber models with free defect,intrinsic point defects and interstitial Bi0 were constructed by Molecular Dynamics method.The first-principles method was used to optimize the structure and static optimization of the constructed model.(2)Luminescence mechanism of interstitial Bi0 doped silica optical fiber.By studying the equilibrium position of interstitial Bi0 atoms in the silica optical fiber,it is found that interstitial Bi0 is most likely to stay around?2 A from the center of six-membered rings.By comparing the transition energy levels with atomic spectrum of Bi atoms,it is found that the near-infrared luminescence of interstitial Bi0 doped silica optical fiber at?1265 nm is caused by the 2D3/2(1)?4S3/2 transition of interstitial Bi0.(3)Reaction mechanism between interstitial Bi0 and intrinsic point defect.The reaction paths of interstitial Bi0 and four intrinsic point defects(ODC(I),POL,NBOHC-E' and POR-E')in silica optical fiber were calculated.By comparing the electronic structure and optical properties of four reaction products,it was found that the reaction of interstitial Bi0 and ODC(I)defect formed a complex,and there was an absorption peak in the near-infrared band of 1400-1500 nm.