Abstract: This paper reviews the work performed under the
European ESPRIT project DO_ALL (Digital OpticAL Logic
modules) spanning from advanced devices (semiconductoropticalamplifiers) to all-optical modules (laser sources and gates) and
from optical signal processing subsystems (packet clock recovery,
optical write/store memory, and linear feedback shift register) to
their integration in the application level for the demonstration of
nontrivial logic functionality (all-optical bit-error-rate tester and
a 2 2 exchange–bypass switch). The successful accomplishment
of the project¢s goals has opened the road for the implementation
of more complex ultra-high-speed all-optical signal processing
circuits that are key elements for the realization of all-optical
packet switching networks.
Abstract: In this paper we discussed different switch architectures. We focus mainly on optical buffering. We investigate an all-optical buffer architecture comprising of cascaded stages of quantum-dot semiconductoroptical amplifier- based tunable wavelength converters, at 160 Gb/s. We also propose the optical buffer with multi-wavelength converters based on quantum-dot semiconductoropticalamplifiers. We present multistage switching fabrics with optical buffers, where optical buffers are based on fibre delay lines and are located in the first stage. Finally, we describe a photonic asynchronous packet switch and show that the employment of a few optical buffer stages to complement the electronic ones significantly improves the switch performance. We also propose two asynchronous optical packet switching node architectures, where an efficient contention resolution is based on controllable optical buffers and tunable wavelength converters TWCs.
Abstract: The authors demonstrate an optical buffer architecture which is implemented using quantum dot semiconductoropticalamplifiers (QD-SOAs) in order to achieve wavelength conversion with regenerative capabilities, for all optical packet switched networks. The architecture consists of cascaded programmable delay stages that minimise the number of wavelength converters required to implement the buffer. Physical layer simulations have been performed in order to reveal the potential of this scheme as well as the operating and device parameters of QD-SOA-based wavelength converters. The results obtained have indicated that, up to three time-slot interchanger (TSI) cascaded stages show good performance at 160 Gb/s in the 1550 nm communication window.
Abstract: The objective of this research is to propose two new optical procedures for packet routing and forwarding in the framework of transparent optical networks. The single-wavelength label-recognition and packet-forwarding unit, which represents the central physical constituent of the switching node, is fully described in both cases. The first architecture is a hybrid opto-electronic structure relying on an optical serial-to-parallel converter designed to slow down the label processing. The remaining switching operations are done electronically. The routing system remains transparent for the packet payloads. The second architecture is an all-optical architecture and is based on the implementation of all-optical decoding of the parallelized label. The packet-forwarding operations are done optically. The major subsystems required in both of the proposed architectures are described on the basis of nonlinear effects in semiconductoropticalamplifiers. The experimental results are compatible with the integration of the whole architecture. Those subsystems are a 4-bit time-to-wavelength converter, a pulse extraction circuit, a an optical wavelength generator, a 3 x 8 all-optical decoder and a packet envelope detector.
