Application of Brillouin-Based Continuously Tunable Optical Delay Line to Contention Resolution Between Asynchronous Optical Packets

A novel approach for resolution of contentions between asynchronous optical packets, exploiting a self-synchronizing mechanism by means of dynamic all-optical tunable delay line based on stimulated Brillouin scattering in fibers, is reported. Time delay between contending optical packets is mapped into the output timing of a contention-detecting pulse produced by the tunable delay line. The output pulse from the delay line triggers an integrated all-optical flip-flop that generates a synchronized gating signal driving a semiconductor-based all-optical switch, for low-priority packets deflection. Correct operation of the proposed scheme without bit loss or packet fragmentation is demonstrated, and error-free operation for the switched packets is reported under different cases of relative delay between incoming optical packets. The scheme operates entirely in the photonic domain and exploits integrated optical switches and a passive optical-delay line for minimized node latency. Extension to symmetric operation allowing priority swapping between the input packets is also proposed.