Billiard Ball Soliton Interaction Gates

We demonstrate a temporal, conservative-logic interaction gate that can perform AND, inversion and routing functions. The billiard-ball like logic is based on elastic collisions between temporal solitons in optical fibers. Fredkin and Toffoli [1] introduced an interaction gate (Fig. 1a) as a universal, conservative-logic primitive and discussed a spatial implementation using the collision between billiard balls where the logic operation corresponds to the locus of the balls (Fig. 1b). The fundamental interest in the interaction gate results from the reversibility of the operation; i.e. the input values can be reconstructed from the output states. However, conservative, reversible gates may have limited practical value since generally they do not have logic level restoration (such as in digital gates) and they may not have gain or fan-out.