Abstract
We have used tight-binding theory to derive an analytic expression describing the dispersion relation of defect mode in a line defect photonic crystal waveguide (PCW). With this expression, group velocity and dispersion coefficient can be directly obtained and pulse propagation in the PCW can be easily characterized. We discuss both line defect and coupled cavity PCWs in this paper. Group velocity, dispersion coefficient and pulse propagation in both PCWs are calculated and compared with the previous reports and the FDTD simulation. The results show reasonable good agreement with the previous reports and our FDTD simulation.