Tunable polarization converter based on ordered AlGaInP waveguide structures

An electrically tunable transverse electric/transverse magnetic polarization converter using ordered AlGaInP waveguide structures is presented. The structures are grown on (001) GaAs substrates with the surface tilted 6° towards {111}B. This selects one of the two possible {111}B variants for the ordering planes. Thus, also on a macroscopic scale, the symmetry of the planar waveguide is broken. The properties of the guided modes are very sensitive to the size and orientation of the axes of the dielectric tensor. So a slight modification of their magnitudes due to electrorefraction leads to a remarkable change in the propagation constants. This change is used to accomplish tunable rotation of polarization by 90°.