DETERMINATION OF 2-DIMENSIONAL OPTICAL WAVE-GUIDE INDEX DISTRIBUTION FUNCTION PARAMETERS FROM EFFECTIVE INDEXES

A method is described for determining two-dimensional (2-D) waveguide refractive index distribution function parameters from effective indexes. Using the least squares method, it gives the most likelihood estimate of the parameters. The practicality of this method is demonstrated by applications to three types of refractive index distribution. First, the convergence of this method is shown by computer simulations of an exponential refractive index distribution. Second, a Ti-diffused LiNbO3 waveguide is considered as an example of Gaussian refractive index distribution. The computed refractive index distribution agrees with the computational results of Fouchet et al.’s experimental formula. Third, a proton-exchanged LiNbO3 waveguide is considered as an example of step refractive index distribution. The computed depth of the waveguide agrees with the measured depth. © 1990 IEEE