The Study Of The Ion-exchanged Waveguide

Graded-index waveguide is one of the most important components in optics communication and integrated optics and it has been widely used. People have paid more attention to the graded-index optical waveguides formed by ion-exchanged for its easy fabrication and low transmission loss. And the characteristics of the modes and the transmission in such waveguides are mostly dependent on their refractive index profiles (RIP). Therefore, determination of refractive index profiles of the graded-index waveguides has been a significant work recently, which can provide much useful information in the fabricating process. By now, many methods have been developed to solve this problem such as ellipsometric method, inverse WKB method, and interferometric method et.al., of which inverse WKB method has been widely used for its clear physical meaning and simple calculation process. However, WKB is a proximate method, the accuracy of the result is dependent on the RIP of the graded-index waveguide. It will be relatively precise in solving the planar waveguides with slow changing RIP, and has large deviation in solving the ones with fast changing RIP. This limitation also exists in its inverse method. We present an inverse analytic transfer matrix (IATM) method to reconstruct the RIP of the graded-index waveguide. It has overcome the internal deficiency of the inverse WKB method since analytic transfer matrix method is exact in any cases. Through calculating some typical types of the RIP, we find that IATM method is much more accurate than inverse WKB method.Surface refractive index is of great significance because it will directly influence the whole RIP in the calculation process. But the value of the Surface refractive index is obtained only through some mathematic analysis such as making the RIP...