Analysis of asymmetric Bragg–coupler based optical add-drop multiplexer operating on certain phase-matching conditions

Abstract

The operational characteristics of a two-dimensional optical add-drop multiplexer were investigated for coupled planar waveguides with embedded grating structure in one of them. The analytical formulation of the wave propagation property was carried out on the basis of coupled mode theory derived from the Lorentz reciprocity theorem. Simplified mathematical formulation and analytical solution for the device modeling were attained by means of well-defined phase-matching conditions. Further numerical analysis was performed to study the effects of various geometrical and material parameters on the device performance in terms of the drop reflectance, input insertion loss, the transmission bandwidth, and the midgap separation. The optimal performance characterized by 99% drop reflectance, 1% input insertion loss, and 0.2 nm full width at half maximum at λ=1.55 μm was achieved with realistically chosen device parameters consisting of refractive indices of the materials and geometrical parameters of the system. This result has demonstrated in principle the feasibility of developing the model for dense wavelength division multiplexing application.