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

Abstract

Abstract-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.

Optical Switching Data Center Networks: Understanding Techniques and Challenges

“…Thus, packet contention resolution is another unsolved challenge that needs to be solved to guarantee fast switch control. Several solutions have been proposed to address such issue, based either on wavelength conversion [125], optical fiber delay lines (FDLs) [126] or deflection routing [127]. However, none of them is practical for large-scale DCNs, due to the extra hardware deployment of wavelength conversion, fixed buffering time of FDLs and the management complexity of deflection routing.…”

Hybrid access network architecture for datacenter based on asynchronous optical packet switching

“…As to the lognormal distribution, the probability distribution of k data in system with one new incoming data is: ( τ (7) AOTDLs are implemented as a distributed contention resolution scheme in the hybrid datacenter. And (6) and (7) could be expressed as the PLR and data waiting delay.…”

“…Although optical buffer technology is still not immature, several different kinds of all optical tunable delay lines (AOTDLs) have been proposed over past few years. And it is demonstrated the AOTDLs can supply optical buffering, pattern recognition, and random reading/writing of memories at a photonic level [7]. Therefore more flexible contention resolution and decreased time delay can be achieved through deploying AOTDLs in datacenter.…”