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Mechanism of Radiation Induced Loss in Optical Fibers and Development of Radiation-Resistant Fibers

光纤辐射损耗机理及抗辐射光纤的发展

基本信息

批准号：
60460123
负责人：
OHKI Yoshimichi
金额：
$ 3.07万
依托单位：
WASEDA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-60460123/
关键词：
Optical Fibers Pure Silica Glass Optical Absorption Bands Defects ノン・ストイキオメトリ

项目摘要

Various optical absorption bands are induced in <gamma> -ray irradiated pure-silica-glass. The cause of seven of these absorption bands, existing in the UV to near IR regions, were not understood. Using ESR and optical absorption experiments, we show that four of these bands can be explained by factors such as impurity content (Cl, OH groups), and nonstochiometry between Si and O in the glass. In the course of the investigation, we found that a fiber with good radiation resistance characteristics is not necessarily a high OH content fiber, as was previously believed.In a number of fibers, the growth of radiation induced defects is different even though the impurity content of the fiber is basically the same. This rather unusual phenonena is caused by stoichiometric imbalance of the ppm order between oxygen and silicon. In oxygen excessive glass, peroxy radicals ( Si-O-O・ ) are formed from either oxygen molecules or other excess oxygen such as peroxy linkages. In oxygen deficient glass on the other hand, the 245nm absorption (caused by Si-Si Bonds ) is observed. Molecular orbital calculations show that in order for the Si-Si bond to be the cause of the 245nm absorption, the distance between the two Si atoms must be 3.08 A. This distance is very near the distance between Si and Si in a normal Si-O-Si bond, which is 3.10 A. These results indicate that the structure of silica glass used as the core in optical fibers is far more orderly than previously believed.

在<gamma>紫外光辐照下，纯石英玻璃产生了不同的光吸收带。这些吸收带中有7个存在于紫外到近红外区域，其原因尚不清楚。使用ESR和光吸收实验，我们表明，这些频带中的四个可以解释的因素，如杂质含量（Cl，OH基团），和非stochiometry之间的Si和O的玻璃。在研究过程中，我们发现具有良好抗辐射特性的纤维并不一定是高OH含量的纤维，在许多纤维中，即使纤维的杂质含量基本相同，辐射诱导缺陷的生长也是不同的。这种相当不寻常的现象是由氧和硅之间ppm数量级的化学计量不平衡引起的。在氧过量玻璃中，过氧自由基（Si-O-O·）由氧分子或其他过量氧（例如过氧键）形成。另一方面，在缺氧玻璃中，观察到245 nm吸收（由Si-Si键引起）。分子轨道计算表明，要使Si-Si键成为245 nm吸收的原因，两个Si原子之间的距离必须为3.08 A。该距离非常接近正常Si-O-Si键中Si与Si之间的距离，其为3.10 A。这些结果表明，用作光纤芯的石英玻璃的结构比以前认为的要有序得多。