Design and analysis of novel multimode optical filters in dielectric waveguide

A new multimode filter design for wavelength multiplexing/demultiplexing applications is investigated. An asymmetric bend generates a number of higher-order modes with appropriate amplitudes from a single-mode incident wave containing two wavelengths. These modes, after travelling along a straight section of multimode waveguide, are recombined in the output Y-branch in such a way that the optical signals at two wavelengths are split and redirected toward different output branches. The structure is analyzed by a combination of finite-difference/time-domain (FD/TD) procedure and a recently developed physical optics method. Numerical results on a sample structure are presented and issues related to the accuracy of results are addressed