Header recognition by use of soliton interaction in fibers

We report an experimental demonstration of optical header recognition that utilizes phase-dependent soliton interaction. A probe word composed of optical solitons is copropagated with a data word while cross-phase modulation from the data bits alters the soliton phases. During subsequent propagation the result of interaction between the solitons depends on the data pattern and is used to identify a desired data word. The method is noncorrelational, has a high contrast, and uses a pattern-detection threshold that does not depend on the desired data pattern. We have demonstrated recognition of 8-bit words at 63 Gbits/s with this technique.