Dielectric bypass waveguide mode order converter

The mode conversion characteristics of a bypass waveguide mode order converter, whose structure is a dielectric waveguide which divides into two branches that later unite with small dividing and uniting angles, are studied experimentally. The working principle of the mode order converter is based on adiabatic mode propagation in the branching waveguide. The features of the device are: 1) it can realize multimode order conversions at the same time, and 2) it does not require phase matching between coupled modes, which relieves the severe tolerance restriction placed on the conventional mode converter with uniform waveguide parameters.