Surface waves at the boundary of a system of coupled waveguides

Experimental investigations of surface waves at the interface between a homogeneous medium and a periodically stratified medium representing a restricted system of coupled waveguides are analysed. It is found that in all cases of the observation of surface waves a restricted system of waveguides has its own spectrum of guided modes and the spectrum of leaky modes, which become the surface waves of the system. It is shown that when two surface waves are used in a biosensor scheme, they should be realised as leaky modes of a Bragg waveguide in which a periodic system of waveguides was used as a distributed Bragg mirror of this waveguide. It is pointed out that the prism method of excitation of surface waves can be used in sensors, where these waves are employed as a detecting tool.