A vectorial time-domain simulator of integrated optical structures containing second order nonlinearities is presented. The simulation algorithm is based on the direct solution of nonlinear Maxwell's equations representing the propagating fields and is solved using the FDTD method. Because the proposed algorithm accounts for the full optical coefficient tensor, the inaccuracies associated with the scalar and paraxial approximations are avoided. It should find application in a wide range of device structures and in the analysis of short-pulse propagation in second order nonlinear devices
