Two-dimensional photonic crystal heterostructure for light steering and TM-polarization maintaining applications

An attractive and realizable scheme of a compact two-dimensional (2D) photonic crystal (PhC) heterostructure is proposed for flexible light steering formed by integrating two PhC structures having diverse optical properties. The first PhC allows both TE- and TM-polarized light to propagate through it with minimum transmission loss (TL), whereas the second PhC structure is designed in such a way that TE-polarized light faces a photonic bandgap while self-collimated TM-polarized light travels without any diffraction. The study is conducted via a 2D finite element method. By the distinctive arrangement of both PhC structures, it is possible to obtain a TM-polarization maintaining device that offers a high polarization extinction ratio of ∼49 dB as well as a compact 180° bend for TE-polarized light with low TL. The proposed study is useful in designing PhC waveguides with sharp bends, which can be employed for multiple applications in photonic integrated circuits.