Three-dimensional calculation of propagation losses in photonic crystal waveguides

Overall losses of optical waveguides, patterned in a two-dimensional photonic crystal in InP-based material system, are determined through the calculation of propagation properties by means of a full three-dimensional finite difference time domain code. Intrinsic origins of the losses related to injection, radiation and diffraction phenomena are more specially addressed, qualitatively and quantitatively. Various configurations including thick substrate and membrane-like approaches are tested. The results, compared to the best published experiments, validate our approach as a predicting tool and give trends for the design of competitive devices.