Interference of signals in parallel waveguides in a two-dimensional photonic crystal

The interference of signals in parallel waveguides in a two-dimensional photonic crystal is studied and compared for two different types of waveguides, namely, an air waveguide formed by removing a row of dielectric columns, and a dielectric waveguide formed by introducing a dielectric slab inside the photonic crystal. For the case of air waveguides, two such parallel waveguides should be separated by at least five rows of dielectric columns to avoid interference between signals (with frequencies in the band gap) traveling in different waveguides. For the case of dielectric slab waveguides, one can achieve very low energy leakage (with negligible interference) between two such waveguides even if they are separated by only a single row of dielectric columns. A dielectric slab waveguide in a photonic crystal is more efficient for confining the electromagnetic energy inside the waveguide than an air waveguide in the photonic crystal. (C) 2001 Elsevier Science B.V. All rights reserved.