Realistic two-dimensional models for planar photonic crystal devices

摘要

We have studied tapers that couple light from a conventional ridge waveguide into a planar photonic crystal (PhC) waveguide. Tapering is achieved by changing the PhC waveguide width either in steps or gradually. Lag effects in fabrication provide an additional tapering due to the fact that the hole depths scale with the corresponding hole diameter. Our analysis deals with the out-of-plane loss that arises within such taper sections. The PhC consists of a triangular lattice of air holes introduced into an InGaAsP/InP slab structure. For conceptual studies we use the 2D multiple multipole method (MMP) in conjunction with an extended phenomenological model. This model covers the out-of-plane scattering providing a loss parameter and an effective index correction for the holes under consideration. This realistic 2D model is retrieved from full-wave 3D FDTD simulations and measurements.