Optimum switching characteristic of nonlinear optical loop mirror and its application to inline all-optical repeater

We design the nonlinear optical loop mirror (NOLM) to have the optimum switching characteristic and study the performance of the designed NOLM as a part in all-optical repeater in non-dispersion-compensated system. The optimum switching characteristic is achieved by scanning the signal pulse in time axis with the control pulse. This scheme induces the phase shift on each signal component equally, preventing the occurrence of the frequency chirp and pulse compression. By numerical simulations, we demonstrate that the signal can propagate in 40-Gbit/s non-dispersion-compensated system that employs NOLM for 100 km, which is 50 km longer than the system without NOLM.