标题：PLANAR WAVE-GUIDE REFRACTIVE-INDEX DISTRIBUTION-FUNCTIONS DETERMINED PRECISELY FROM MODE INDEXES
作者：MU, XD; YUE, XF; CHEN, J; WANG, JY; SHAO, ZS
通讯作者地址：[MU, XD]SHANDONG UNIV, INST CRYSTAL MAT, JINAN 250100, PEOPLES R CHINA.
关键词：WAVE-GUIDE; INDEX DISTRIBUTION FUNCTION; IWKB APPROXIMATION
摘要：The inverse WKB (IWKB) approximation has been extended to derive the index distribution functions from the measured mode indices of a planar waveguide. Through the use of this technique, the forms of the index distribution functions are obtained by IWKB approximation and a criterion is used to derive the functions accurately. The results are compared to the exponential and Fermi distributions. It is shown that the index profile, surface index, and waveguide depth can be obtained more accurately than with the original IWKB approximation. Finally, the index distribution function of a c-cut proton-exchanged LiTaO3 waveguide is given by this technique, the mode indices calculated with this function agree with the experimental results in the range of 10(-4).