A New method for the recovery of the refractive-index profile of an optical waveguide from the measured coupling angles

摘要

In this ppaer, we present a new method used for the recovery of the refractive-index prifle of an optical waveguide from the measured coupling angles. Two improvements have been made in our method. First, we determine the surface refractive index of the inhomogeneous waveguide by experimenttechnique, instead of usual numerical methods. Second, we present a new fitting criterion which is based on the accurate ATMM (Analytic Transfer Matrix Method~t), but not approximate WKB theory. Experimental results demonstrate our method could give better results compared with the previous techniques.