| Scope and method of study. The purpose of this study was to examine the cross Kerr and Raman effects on the switching efficiency of soliton optical fiber gates. Analytical propagation models were derived via the reductive perturbation method, and the numerical propagation models via the symmetrized split-step Fourier method. Zero propagation attenuation is assumed. The second and higher order dispersion parameters, in the two orthogonal axes of the strongly birefringent fiber, are assumed to be equal.; Findings and conclusions. The traditional propagation equation of two orthogonally polarized solitons, in a strongly birefringent singlemode fiber, is significantly modified by the introduction of cross steepening and cross frequency shifting effects. Co-propagation numerical solutions of the coupled nonlinear Schrodinger equation, using the symmetrized split-step Fourier method, were used to simulate an inverter soliton trapping gate (STG), inverter soliton dragging gate (SDG), and two newly discovered soliton optical fiber gates. The two newly discovered gates are the STG-NOLM gate (NOLM stands for nonlinear optical loop mirror), and the STG-PSI-NOLM gate (PSI stands for partial shuffle interaction). It was found that the inverter STG, with the control pulse on the fast axis, is much more immune to the delay effects introduced by the higher order nonlinear and dispersion effects. The STG is still capable of switching efficiently under these delaying effects. The inverter SDG, however, is less immune to these effects, especially when the control pulse is on the slow axis (at angle 30°). The clock time window needs only to be slightly reduced for the SDG, when the control pulse is on the fast axis (at angle 60°). Inference from these results indicates that a STG is better than a SDG, when operated under the higher order nonlinear and dispersion effects. The switching performance of the STG-PSI-NOLM gate (with segment length equal to walk-off length) is very superior to the STG-NOLM gate, which has very poor switching characteristics, and the output control pulse transmission of both gates are only slightly attenuated by the higher order nonlinear and dispersion effects. Control and signal pulses of 50 fs (FWHM) at 1.55 m m were used, with a total soliton amplitude of 1.24, and birefringence of 1.1103 x 10--4. |
