Reconstruction of Optical Waveguide Index Profiles by Using Down-hill Simplex Method on the Fitting of Near-field Distribution

• Main Authors: Yu-Rung Lin, 林譽融
• Other Authors: Way-Seen Wang
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/71761857958796840308

碩士 === 國立臺灣大學 === 電子工程學研究所 === 98 === Refractive index profile reconstruction of diffused optical waveguides is presented. The process starts with an index model that is a product of an error function for the width direction and a Gaussian function for the depth direction, and then the field distribution is solved numerically. Using the down-hill simplex method, three parameters of the index model are obtained by best fitting the measured near-field distribution. To check the accuracy of the index profile, straight waveguides and directional couplers are fabricated under the same process condition. Then the coupling lengths are measured and compared with those simulated by available software with the reconstructed index profiles. The results show the errors are within 10%.