Optical surface modes of photonic crystals for dual-polarization waveguide

In this study, the design of a polarization-independent (dual-polarization) waveguide is presented by utilizing surface modes of photonic crystals. The waveguide structure operates in a frequency interval that is commonly shared by both transverse-electric (TE) and transverse-magnetic (TM) polarizations. The numerical calculations based on plane wave expansion and finite-difference time-domain methods are carried out to design and demonstrate a surface mode waveguide that provides confinement and guiding for both TE and TM modes. Once the relevant modes are properly excited, the high transmission efficiency of the photonic crystal surface waveguide is ensured. The demand to have polarization-insensitive devices makes our proposed design an important component for the photonic integrated circuit applications. Finally, we also propose a broadband surface mode photonic crystal waveguide with a bandwidth value of 28% for only TE polarization.

► The optical surface Bloch modes are utilized for the first time in order to design a polarization-insensitive waveguide. ► The designed waveguide has 4.6% bandwidth which is comparable with the literature. ► The second design that operates for only TE polarization has a bandwidth of 28%. This bandwidth is very high with respect to the other studies. ► The wideband TE waveguide is low loss and low dispersive.