| Summary: | 碩士 === 國立臺灣大學 === 電機工程學研究所 === 88 === This thesis reports an iterative finite difference method for index profile reconstruction from near-field. First, we introduce some experimental techniques for the determination of the index profiles of optical waveguides. Then, we implement two methods for the index profile reconstruction from near-field. The index reconstruction method based on the inversion of wave equation is influenced dramatically by high-spatial frequency noise, especially when the intensity is low. Oppositely, the method based on the iterative finite difference method has a low sensibility to spatial noise and gives precise results. Last, applications of the method to some different waveguides was presented. The iterative finite different method is a nondestructive technique, and it can help us to reconstruct index profile precisely.
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