Joenathan C, Bunch R M
Appl Opt. 1993 Oct 20;32(30):5989-96. doi: 10.1364/AO.32.005989.
Two methods to measure the cladding diameter of single-mode fibers are presented. The first method is based on an interference fringe measurement technique. Interference fringe spacing at two different planes is measured to determine the cladding diameter of the fiber. The theory of the fringe formation in the interferometeric arrangement using single-mode fibers is discussed. It is theoretically shown that the far-field overlapping Gaussian field distribution from the fibers shifts the position of the fringe maxima and minima. As a special case of unit fringe visibility the minima positions do not shift, whereasthe maxima positions are shifted. In the case of a Lloyd mirror arrangement it is shown that fringes can be obtained from a rough surface as well. A lens is used in the second method to image the two identical point sources that cause the interference. Through the use of the magnification and spacing of the images, the cladding diameter is estimated. It is shown that the accuracy of the fiber cladding-diameter measurement can be enhanced by generating multiple point sources. Consistent results of the fiber cladding diameter have been obtained with the proposed methods. Fiber cladding-diameter measurements with a standard error of less than 0.15 µm can be achieved.
介绍了两种测量单模光纤包层直径的方法。第一种方法基于干涉条纹测量技术。通过测量两个不同平面处的干涉条纹间距来确定光纤的包层直径。讨论了使用单模光纤的干涉仪装置中条纹形成的理论。从理论上表明，来自光纤的远场重叠高斯场分布会使条纹的最大值和最小值位置发生偏移。作为单位条纹可见度的一种特殊情况，最小值位置不发生偏移，而最大值位置发生偏移。在劳埃德镜装置的情况下，表明也可以从粗糙表面获得条纹。第二种方法使用透镜对产生干涉的两个相同点光源进行成像。通过利用图像的放大倍数和间距来估计包层直径。结果表明，通过产生多个点光源可以提高光纤包层直径测量的精度。使用所提出的方法已获得了一致的光纤包层直径测量结果。可以实现标准误差小于0.15 µm的光纤包层直径测量。
