Cross-phase modulation response of a DCC-DFB-SOA all-optical flip-flop

Using the coupled-mode and carrier rate equations, we have derived a dynamic model for the distributed feedback semiconductor optical amplifier (DFB-SOA) all-optical flip-flop (AOFF). We have analyzed the effects of the coupling coefficient and the corrugation position on the dynamic response of the device. We have also investigated the effects of cross-phase modulation on the switching speed of the DFB-SOA with the distributed coupling coefficient (DCC), known as the DCC-DFB-SOA AOFF. Furthermore, it is shown that by optimizing the coupling coefficient value and the corrugation position, the AOFF speed limitation is improved significantly. The ON and OFF switching time values, in an optimized condition, are 300 and 100 ps, respectively, while the carrier lifetime is about 780 ps. In comparison with those of a conventional DFB-SOA-AOFF, these values show reductions of more than 2 and 14 times in the ON and the OFF switching times, respectively. Under such conditions, a maximum bit rate of 1.4 GHz is achieved. The finite difference time-domain method is utilized for the numerical simulations.