This paper reviews the work carried out under the European ACTS KEOPS (KEys to Optical Packet Switching) project, centering on the definition, development and assessment of optical packet switching and routing networks capable of providing transparency to the payload bit rate. The adopted approach uses optical packets of fixed duration with low bit rate headers to facilitate processing at the network/node interfaces. The paper concentrates on the networking concepts developed in the KEOPS project through a description of the implementation issues pertinent to optical packet switching nodes and network/node interfacing blocks, and consideration of the network functionalities provided within the optical packet layer. The implementation, from necessity, relies on advanced optoelectronic components specifically developed within the project, which are also briefly described.

Transparent optical packet switching: the European ACTS KEOPS project approach

In this paper, promising technologies and a network architecture are presented for future optical packet switched networks. The overall network concept is presented and the major choices are highlighted and compared with alternative solutions. Both long and shorter term approaches are considered, as well as both the wide-area network and multiple-area networks parts of the network. The results presented in this paper were developed in the frame of the research project DAVID (Data And Voice Integration over DWDM) project, funded by the European Commission through the IST-framework.

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The European IST project DAVID: a viable approach toward optical packet switching

The motivations and application framework for the introduction of all-optical wavelength division multiplexing (WDM) transmission and routing techniques in the transport network are presented. The requirements and functionalities of all-optical transparent routing nodes are discussed, and the physical architecture of a crossconnection node is proposed, to meet these requirements. Optical devices suitable for the node implementation are compared, and first demonstrations of crossconnection function at data rates up to 10 Gb/s are given. These results bring experimental evidence of the high potential of all-optical routing nodes for actual implementation of multiwavelength transport networks.

Design and implementation of a fully reconfigurable all-optical crossconnect for high capacity multiwavelength transport networks

An on-chip data communications infrastructure includes a hybrid, photonic/electronic network. The network includes a plurality of interconnected optical switches, each under the control of an electronic router. The electronic routers are connected in a fashion similar to the optical switches, forming a parallel, photonic/electronic network. Electronic path setup messages are routed through the electronic network. At each hop, a photonic switching element in a parallel, photonic network is reserved. When the electronic path setup message reaches its destination, a chain of reserved optical switches is ready to channel the optical data through the photonic network.

Systems And Methods For On-Chip Data Communication

In this paper, we present a new concept of optical packet/burst switching suitable for generalized multiprotocol label switched (GMPLS)-based optical networks. In such networks, optical labeled switched paths are being established in a similar way as label-switched paths in MPLS. We use a wavelength label as well as an orthogonally modulated label, with respect to the payload modulation format, and which is encoded using either frequency-shift keying (FSK) or differential phase-shift keying (DPSK). Wavelength is used for switching in the node, whereas the orthogonal label defines the label-switched path. We present both simulation and experimental results to assess transmission performance of the proposed combined modulation scheme. In addition, we propose a suitable optical node architecture that can take advantage of this stacked label concept. Toward this, we use widely tunable wavelength converters to efficiently route IM/FSK (or IM/DPSK) optically labeled packets in an arrayed-waveguide grating (AWG)-based node structure. We present performance simulation results in terms of packet loss ratio and internal block probability. Internal blocking is an inherent problem of AWG optical routers, and a specific wavelength assignment algorithm has been developed to minimize it. Finally, the feasibility of IM/FSK transmission is experimentally demonstrated over an 88-km single-mode fiber span, and novel aspects of FSK generation and detection techniques are presented.

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An optical IM/FSK coding technique for the implementation of a label-controlled arrayed waveguide packet router

Summary form only given. Recently, arrays of four clamped gain semiconductor optical amplifiers (CG-SOAs) which were fully packaged have been reported with excellent performances using bulk tensile strained active material. Here we believe we present for the first time subnanosecond switching of such a four CG-SOA array driven by integrated InP HBT drivers.

Fast optical amplifier gate array for WDM routing and switching applications

In this paper, we present a high performance, versatile multifibre pigtailing technique adapted to tilted semiconductor optical amplifier arrays. Dynamic alignment of collectively processed tilted lensed ribbon fibre and YAG laser welding assembly are used for pigtailing of 4 clamped gain semiconductor optical amplifier array. The collective process makes this packaging technique attractive for array components. This paper describes the technology used and summarizes main results obtained on fabricated modules.

High performance packaging technique used for clamped gain semiconductor optical amplifier array modules fabrication

A generic waveguiding structure is reported with low coupling loss (/spl les/1 dB/facet) with lensed fibers and low propagation loss (/spl les/1 dB/cm). This structure is suitable for low loss guided-wave photonic integrated circuits including active elements such as switches, and passive interconnections such as mirrors, and allows low polarization dependent operation. Which is required for instance in wavelength demultiplexers. This structure based on a single epitaxy is of interest for low cost photonic switching fabrics. >

Low-loss fiber-chip coupling by InGaAsP/InP thick waveguides for guided-wave photonic integrated circuits

InP 4 x 1 digital-optical-switch module for multiwavelength cross-connect applications

The first demonstration of optical packet switching with an InP monolithic 16-channel wavelength selector module is reported. Switching time below 5 ns, wide input power dynamic range of 15 dB, average polarisation dependent loss below 2 dB, and error free transmission are demonstrated.

J. Le Bris

Papers

Fast optical amplifier gate array for WDM routing and switching applications

High performance packaging technique used for clamped gain semiconductor optical amplifier array modules fabrication

Low-loss fiber-chip coupling by InGaAsP/InP thick waveguides for guided-wave photonic integrated circuits

InP 4 x 1 digital-optical-switch module for multiwavelength cross-connect applications

First optical packet switching demonstration with sixteen-channel InP monolithically integrated wavelength selector module