Surface waves on the boundary of photonic crystals and tunnelling coupling between two photonic crystals via these waves

Based on coupled Nb₂O₅—SiO₂ waveguides, one-dimensional photonic crystals are fabricated and surface waves at 0.63 μm are generated at their boundary with air. A planar Bragg waveguide with an air core is fabricated due a contact of two photonic crystals through an air gap. The propagation constants of the symmetric and antisymmetric modes of the Bragg waveguide are measured and the value of the air gap of the waveguide is estimated. It is shown that, to obtain the fundamental modes of the Bragg waveguide based on the used waveguides, it is necessary to shift the working wavelength to the red and to increase the thickness of the air gap of the Bragg waveguide.