Directional coupler based on bent channel waveguides formed by K+-ion diffusion in glass

Bent channel waveguides, formed by the diffusion of K+ ions in glass, were used in a directional coupler with the efficiency of the transfer of power between the channels in the range 0.1–44%. The process of propagation of light in a directional coupler with two-mode bent channel waveguides, formed by K+-ion exchange, was investigated. The results show that such a coupler could be used as a mode selector.