OTDM add-drop multiplexer based on XPM-induced wavelength shifting in highly nonlinear fiber

In this paper, we study experimentally and numerically simultaneous time-domain add-drop multiplexing for high-speed optical time-division multiplexing (OTDM) networks based on cross-phase-modulation (XPM)-induced wavelength shifting in a 50-m highly nonlinear fiber. This scheme needs only a single-channel clock rate and does not alter the input signal wavelength. Simultaneous add and drop operations at 80 Gb/s have been demonstrated experimentally with less than 1-dB power penalty for the dropped channel and no distinct bit-error-rate (BER) degradation for the added channel. Numerical simulations show that the experimental results are only limited by the available signal pulsewidth, and simultaneous add-drop multiplexing at 160-Gb/s or higher bit rates is possible with this scheme by employing control and signal pulses with proper pulsewidths.