Stone J, Burrus C A
Appl Opt. 1975 Jan 1;14(1):151-5. doi: 10.1364/AO.14.000151.
The effects of ray bending due to graded refractive-index profiles have been studied in relation to the measurement of optical-fiber refractive-index profiles by microscopic interferometric techniques. In particular, the wavefront curvature produced by a simple parabolic profile has been calculated analytically. It is concluded that profile measurements by currently used methods require samples for which the fiber thickness (length) is much less than the effective focal length of the fiber. For parabolic profile fibers with diameter d greater, similar 100 microm, this poses no problem; however, for small-core versions of this fiber, sample thicknesses of 10-15 microm may be required and an alternate measurement technique is described. Interferograms made on a Leitz transmitted-light interference microscope are included in illustrations.
已针对通过微观干涉测量技术测量光纤折射率分布的问题，研究了渐变折射率分布引起的光线弯曲效应。特别地，已通过解析计算得出了由简单抛物线分布产生的波前曲率。得出的结论是，采用当前使用的方法进行分布测量时，所需样品的光纤厚度（长度）应远小于光纤的有效焦距。对于直径d大于约100微米的抛物线分布光纤，这不成问题；然而，对于这种光纤的小芯径版本，可能需要10 - 15微米的样品厚度，本文描述了一种替代测量技术。插图中包含了在徕卡透射光干涉显微镜上制作的干涉图。
