2D-Photonic crystal heterostructures for the realization of compact photonic devices

Abstract

Herein, we presented a novel design of polarization beam splitter (PBS) based on the integration of heterostructure 2D- Photonic crystals (PhCs). Two PhC structures, namely PhC-type 1 and PhC-type 2, with different transmission characteristics are proposed. The first type of PhC is composed of a 2D-periodic array of circular air holes embedded in silicon substrate which facilitates the propagation of self-collimated TE and TM-polarized light. The second type of PhC consists of a 2D-periodic array of square-shaped air holes embedded in silicon substrate which carry a photonic bandgap (PBG) for TE-polarized light whereas TM-polarized light propagates unaffected by diffraction. When PhC-type 2 structure is arranged at 45° on both sides of the PhC-type 1 structure, this combination leads to the formation of PBS with a polarization extinction ratio (PER) as high as 30.7 dB. Furthermore, the same structure can be used to steer the TE-polarized light at 180° in a small footprint. Additionally, the heterostructure PhC can be used for TM-polarization maintain devices.