A circular system of coupled waveguides and an optical analogue of bloch oscillations

The process of light propagation in a nonuniform system of tunnel-coupled waveguides is studied. The nonuniform system of waveguides is realized by making a circular system of waveguides on the inner wall of a supporting tube with the help of the SPCVD technology, which is designed for the synthesis of preforms of optical fibers. It is shown that the waveguide light beam propagates in such a system along a wavelike trajectory and partially radiates outwards at the crests of this trajectory. The oscillation period of the trajectory is measured, and it is shown that it is possible to input radiation into the waveguide mode by the process that is inverse to the process of light emission from the structure.