Theory of pulse shepherding in bit-parallel WDM soliton systems

Summary form only given.The successful design of low-loss dispersion-shifted and dispersion-flattened optical fibers with low dispersion over a relatively large wavelength range can be used to reduce or completely eliminate the group-velocity mismatch for the multi-channel WDM systems. If the two co-propagating pulses are widely separated, each pulse propagates independently as if without the presence of the other pulse. However, they can be brought significantly closer to each other by the launching of another pulse on a separate wavelength with the proper magnitude and at the proper time. This pulse is called the shepherd pulse because of its shepherding behavior on the other pulses. We analyse these nonlinear modes, the stationary localised pulses of the WDM model, and provide a deep insight into the physics of the shepherding effect.