An extension of the recently introduced nonlinear finite-difference time-domain technique [Opt. Lett. 21, 1138 (1996)] for the study of electromagnetic wave propagation in a non-linear Kerr medium to include absorption is presented. The optical limiting and switching of short pulses by use of a nonlinear quarter-wave reflector (a one-dimensional photonic bandgap structure) with a defect is studied. Comparison with an optical limiter and with an optical switch with a perfect nonlinear quarter-wave reflector shows that introducing a defect can improve the performance of these devices. (C) 1997 Optical Society of America.
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