Yang Yu-Ching, Lee Haw-Long, Chou Huann-Ming
Department of Mechanical Engineering, Kun Shan University of Technology, Yung-Kong, Tainan County, Taiwan.
Appl Opt. 2002 Apr 1;41(10):1989-94. doi: 10.1364/ao.41.001989.
Stresses, microbending loss, and refractive-index changes induced simultaneously by axial strain and hydrostatic pressure in double-coated optical fibers are analyzed. The lateral pressure and normal stresses in the optical fiber, primary coating, and secondary coating are derived. Also presented are the microbending loss and refractive-index changes in the glass fiber. The normal stresses are affected by axial strain, hydrostatic pressure, material properties, and thickness of the primary and secondary coatings. It is found that microbending loss decreases with increasing thickness, the Young's modulus, and the Poisson's ratio of the secondary coating but increases with the increasing Young's modulus and Poisson's ratio of the primary coating. Similarly, changes in refractive index in the glass fiber decrease with the increasing Young's modulus and Poisson's ratio of the secondary coating but increase with the increasing Young's modulus and Poisson's ratio of the primary coating. Therefore, to minimize microbending loss induced simultaneously by axial strain and hydrostatic pressure in the glass fiber, the polymeric coatings should be suitably selected. An optimal design procedure is also indicated.
分析了双包层光纤中由轴向应变和静水压力同时引起的应力、微弯损耗以及折射率变化。推导了光纤、初级涂层和次级涂层中的横向压力和法向应力。还给出了玻璃纤维中的微弯损耗和折射率变化。法向应力受轴向应变、静水压力、材料特性以及初级和次级涂层的厚度影响。研究发现，微弯损耗随次级涂层厚度、杨氏模量和泊松比的增加而减小，但随初级涂层杨氏模量和泊松比的增加而增大。同样，玻璃纤维中的折射率变化随次级涂层杨氏模量和泊松比的增加而减小，但随初级涂层杨氏模量和泊松比的增加而增大。因此，为使玻璃纤维中由轴向应变和静水压力同时引起的微弯损耗最小化，应适当选择聚合物涂层。还给出了一种优化设计方法。
