Mohammad S. AKOND^*

Department of Electrical Engineering, Najran University, KSA

(Received December 27, 2012; Revised March 8, 2014; Accepted March 8, 2014)

An analysis of ultrashort-pulse interaction inside directional coupler structures having dispersive material is conveyed using the well-known finite difference time domain (FDTD) technique and time domain beam propagation method (TD-BPM). The implicit TD-BPM uses a higher-order non-paraxial equation suitable for femtosecond pulse. The result obtained by the one-way technique is verified with that of the widely used FDTD. A rigorous study is conveyed in order to distinguish material dispersion from intermodal dispersion. The analysis reveals that material dispersion causes energy loss in the device, in addition to extra pulse broadening and splitting that occur to a low extent in the case of intermodal dispersion.

Key words: finite difference time domain, beam propagation method, ultrashort pulse, Padé approximant, intermodal dispersion, dispersive material, interference

^*E-mail address: msakond@nu.edu.sa