Frequency Response of Silicon-Clad Proton-Exchanged Channel Waveguides

Abstract

The annealed proton-exchanged (APE) process has emerged as an important technique for the fabrication of low-loss optical waveguides in LiNbO₃. The propagation characteristics of a silicon-clad X- and Z-cut APE channel optical waveguide are investigated by the semi-vectorial beam propagation method (BPM). Numerical results for several different waveguide structures indicate that the attenuation of channel dielectric waveguides clad with silicon behaves as a damped periodic oscillation with increasing silicon thickness. Results also show that the attenuation of the propagating mode is highly dependent on wavelength. Moreover, this loss characteristic can be controlled by waveguide parameters such as the thickness of silicon-clad and buffer layer. As a result, the silicon-clad proton-exchanged optical waveguides can be used as optical frequency filters.