A Study on Double-Clad Photonic Crystal Waveguides with High Birefringence, Strong Nonlinearity, and Near-Zero Chromatic Dispersion

In this paper, doubly-cladded (DC) photonic crystal waveguides (PCWs), which are different from regular PCWs and have basically 12 air holes in the first inner hexagonal cladding layer, are proposed and investigated by utilizing the rigorous full-vectorial finite difference method (FDM).By appropriately introducing omission defects of air holes in the inner first hexagonal cladding layer, important optical propagation characteristics of small effective mode area (EMA), high birefringence (HB), and near-zero chromatic dispersion are thoroughly presented and compared in the practical operation wavelengths for design goals along with simultaneously effective controllability for the new HB DC-PCWs.The fundamental mode fields for the proposed HB DC-PCWs are tightly confined to the central core region.Therefore, the EMA is normally very small as intended, because the nonlinearity is inversely proportional to the EMA for the fundamental mode.Superior performance for preserving the lightwave polarization state with the HB levels of about 5.310 -4 -7.810 -4 has been achieved with additive advantages of broadly unlimited stable single-mode operation and fabrication from only pure fused silica material.Also since the rigorous full-vectorial FDM approach provides remarkably accurate and reliable computer-calculation results for the signal transmission waveguide, investigation methods of this research predictively can be utilized to manage some specified electromagnetic propagation characterisctics within tolerable error range of design parameters such as air hole sizes during manufacturing process.