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A modular photonic interconnection network based on a combination of basic 2×2 all-optical nodes where a photonic
combinatorial network manages the packet contention, is presented. The proposed architecture is synchronous, can
operate Optical Time Division Multiplexing (OTDM) packets up to 160Gb/s and exhibits self-routing capability and
very low switching latency.
In such a scenario, OTDM has to be preferred to Wavelength Division Multiplexing (WDM), because in the former case
the instantaneous packet power carries the information related to only one bit, making more simpler the signal processing
based on instantaneous nonlinear interactions between packets and control signals. Moreover OTDM can be utilized in
interconnection networks without caring about the propagation impairments, since these networks are characterized by a
very limited size (< 100m). Finally, in such a limited domain, the packet synchronization can be solved at the network
boundary in the electronic domain, without the need of complex optical synchronizers. The 2×2 switching element is
optically managed by exploiting a photonic combinatorial network able to carry out contention detection, and to drive the
contention resolution and the switching controller blocks. The implementation of such photonic combinatorial network
is based on semiconductor devices, making the solution very promising in terms of compactness, stability, and power
consumption. The network performances have been investigated for bit streams at 10 Gb/s in terms of Bit Error Rate
(BER) and Contrast Ratio. Moreover, the suitability of the 2×2 photonic node architecture exploiting the above
mentioned combinatorial network, has been verified up to 160 Gb/s, demonstrating the potentialities of photonic digital
processing in the next generation broad-band and flexible interconnection networks.
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