Electrically tunable birefringence in nanophotonic waveguide with 2D electron gas in semiconductor heterojunction

An electrically tunable birefringence in a nanophotonic waveguide based on MgZnO-CdZnO semiconductor heterojunction is numerically proposed. Electrical control is realized with two-dimensional electron gas (2DEG) at the interface of ZnO based heterojunction and is used to control the polarization. The waveguide is engineered to enhance interaction of guided optical mode(s) with 2DEG providing us with a wide tuning in modal birefringence. We perform numerical analysis of phase and polarization characteristics of 2DEG based nanophotonic waveguide. Electrical tuning of 0.0112 in modal birefringence is reported by varying the applied voltage from 0 Vto −10 V. The proposed device also exhibits voltage variable optical phase modulation in both TE and TM polarizations. The proposed work can be utilized in applications where integrated photonic devices with variable polarization control are desirable.