Numerical calculation of wavelength switching in index-varied array waveguide

Wavelength switching in the index-varied array waveguide is calculated. The device consists of waveguide array in which the refractive index varies gradually across the array and star coupler. In the calculation, the phase differences in each array waveguide, and the diffraction in the star coupler are considered. Refractive index distribution of the array waveguide for wavelength demultiplexing, and index change for switching are obtained.