Reformulation of Coupled-Mode Theory of Parallel Waveguides for Analysis of Arbitrary Beams

Standard Coupled-Mode Theory (Standard CMT), developed for analysis of guided modes in arrays of coupled parallel waveguides, was extended to include analysis of arbitrary optical beams (AB-CMT). This extension bypasses some characteristic limitations of the coupled-mode formalism, existed so far, and thus offers an effective tool for fast and accurate computations of optical beams in the variety of waveguiding devices, matching the model of parallel waveguides (including, but not limited by modern photonic micro-devices). AB-CMT combines analytical capabilities and high computational accuracy with numerically stable algorithms and low time- and resource consumption. Our computations show the close agreement between the results, acquired with AB-CMT, and those received with the well-established Beam Propagation Method (BPM), served as the benchmark.