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2003, Optical Transmission Systems and Equipment for WDM Networking II
Possible switching architectures, with Optically Programmable Logic Cells -OPLCs -will be reported in this paper. These basic units, previously employed by us for some other applications mainly in optical computing, will be employed as main elements to switch optical communications signals. The main aspect to be considered is that because the internal components of these cells have nonlinear behaviors, namely either pure bistable or SEED-like properties, several are the possibilities to be obtained. Moreover, because their properties are dependent, under certain condition, of the signal wavelength, they are apt to be employed in WDM systems and the final result will depend on the corresponding optical signal frequency. We will give special emphasis to the case where self-routing is achieved, namely to structures of the Batcher or Banyan type. In these cases, as it will be shown, there is the possibility to route any packet input to a certain direction according to its first bits. The number of possible outputs gives the number of bits needed to route signals. An advantage of this configuration is that a very versatile behavior may be allowed. The main one is the possibility to obtain configurations with different kinds of behavior, namely, Strictly Nonblocking, Wide-Sense Nonblocking or Rearrangeably Nonblocking as well as to eliminate switching conflicts at a certain intermediate stages.
Le Journal de Physique Colloques
1990
A novel se&!-routed slot-switching scheme using an integmted optic directional cou let is outlined using apulse interval coded optical content dmdle memory ( P I C O W ) . nte integrated optic devices required for its implementation are ako outlined % bit-switching approach avoids the bottleneck in speed imposed by the electronic drive circuitry in electrooptic switches.
Photonic Devices and Algorithms for Computing IV, 2002
Nowadays, in order to take advantage of fiber optic bandwidth, any optical communications system tends to be WDM. The way to extract a channel, characterized by a wavelength, from the optical fiber is to filter the specific wavelength. This gives the systems a low degree of freedom due to the fact of the static character of most of the employed devices. In this paper we will present a different way to extract channels from an optical fiber with WDM transmission. The employed method is based on an Optically Programmable Logic Cells (OPLC) previously published by us, for other applications as a chaotic generator or as basic element for optical computing. In this paper we will describe the configuration of the OPLC to be employed as a dropping device. It acts as a filter because it will extract the data carried by a concrete wavelength. It does depend, internally, on the wavelength. We will show how the intensity of the signal is able to select the chosen information from the line. It will be also demonstrated that a new idea of redundant information it is the way of selecting the concrete wavelength. As a matter of fact this idea is apparently the only way to use the OPLC as a dropping device. Moreover, based on these concepts, a similar way to route signals to different routes is reported. The basis is the use of photonic switching configurations, namely Batcher or Bayan structures, where the unit switching cells are the above indicated OPLCs.
Journal of Lightwave Technology, 2005
Dense Wavelength-division multiplexing (DWDM) technology offers tremendous transmission capacity in optical fiber communications. However, switching and routing capacity lags behind the transmission capacity, since most of today's packet switches and routers are implemented using slower electronic components. Optical packet switches are one of the potential candidates to improve switching capacity to be comparable with optical transmission capacity. In this paper, we present an optically transparent ATM (OPATM) switch that consists of a photonic front-end processor and a WDM switching fabric. A WDM loop memory is deployed as a multi-ported shared-memory in the switching fabric. The photonic front-end processor performs the cell delineation, VPI/VCI overwriting, and cell synchronization functions in the optical domain under the control of electronic signals. The WDM switching fabric stores and forwards aligned cells from each input port to the appropriate output ports under the control of an electronic route controller. We have demonstrated with experiments the functions and capabilities of the front-end processor and the switching fabric at the header-processing rate of 2.5Gb/s. Other than ATM, the switching architecture can be easily modified to apply to other types of fixed-length payload formats with different bit rates. Using this kind of photonic switches to route information, an optical network has the advantages of bit rate, wavelength, and signal-format transparencies. Within the transparency distance, the network is capable of handling a widely heterogeneous mix of traffic, including even analog signals.
Photonic packet switches offer high speed, data rate and format transparency, and flexihility required by future computer com munications and cell-based telecommunications networks. In this paper, we review experimental progress in state-of-the-art pho tonic packet switches with an emphasis on all-optical guided-wave systems. The term all-optical implies that the data portion of a packet remains in opticalformat from the source to the destination.
IET Communications, 2009
Future interconnection networks will be required to achieve ultra-high bandwidth and low latency communications to cope with the increasing performance requirements of backbone routers, large data storage systems and supercomputing systems. Aiming at achieving ultra-high bandwidth communications and approaching optical time-of-flight processing latency while being robust to cascade impairments, the authors propose an all-optical packet-switched interconnection network, where not only the actual packet switching but also the packet processing is performed in the photonic domain. The authors present two modular architectures, based on the crossbar and the Batcher-Banyan topologies, capable of forwarding fixed-length packets with two classes of service. Both use photonic digital-processing subsystems built by combining a single integrable module which exploits cross gain modulation in a semiconductor optical amplifier. System level simulations on the crossbar switch controller guarantee that the control signals maintain an acceptable quality during the processing. Moreover, the Batcher-Banyan configuration is more cost-effective than the crossbar for increasing port count, while effective network performance in terms of packet loss rate can be obtained by adding just few recirculating delay lines.
IEEE Journal on Selected Areas in Communications, 1990
In this paper, an architecture of an all-optical multistage interconnection network is proposed. The network supports a circuit-switching mode of communication and can provide parallel optical paths among input and output ports. It uses an address-based routing algorithm for path setup which, due to its decentraliied nature, makes this network suitable for designing high-speed switching systems. These switches are commonlj used in telephon) and rnultiprocessor systems. The proposed architecture uses bistable optical devices, such as interference filters, as essential componentc of its switching modules. Since these devices can be easily fabricated, the implementation of this architecture is feasible. Various design is\ue5 related to optical clock generation, its distribution, data 5jnchroniiation, and intensity restoration are also discussed. NTERCONNECTION networks play an important role I in telecommunication and multiprocessor systems. In telecommunication, these networks are used to build telephone switching systems [ 11, [2], while in multiprocessor systems they provide an efficient mechanism to transfer information among and between processors and memories. The most well-known interconnection architecture is the crossbar switch. It is a nonblocking network, in that it can provide switching capability from inputs to outputs without contention . However, if the number of inputs (m) and outputs ( n ) are large, the design of an electronic crossbar becomes expensive as it contains m X n switches. Since there is a limitation on the number of pins for a VLSI chip, the size of the largest crossbar that can be integrated into a single chip is restricted . Alternatively, large crossbars can be partitioned into many smaller ones, each of which can be implemented on a single chip. However, this approach faces various important design issues, such as the need for fast reconfiguration time for the overall network, increased control complexity for switches, and minimizing excessive propagation delay through the partitioned networks. Furthermore, the pin limitation poses a major constraint on the number of data channels that can be switched in parallel, and thus restricts broadcasting ability in the network. In order to reduce the number of switching elements, Manuscript
2008 6th International Symposium on Communication Systems, Networks and Digital Signal Processing, 2008
Two new architectures are proposed for designing physical network nodes in packet-switched structures. They allow transparent optical packet networking and are based on the association of various subsystems, which have previously been proposed, and demonstrated. These elements are mainly based on the application of nonlinear behavior in semiconductor optical amplifiers.
Journal of Optical Networking, 2007
We propose an architecture for a WDM-based photonic packet switch. This is a wavelength routed switch in which, once the wavelength of the incoming packet is tuned appropriately, will either be directly transmitted to the output fiber or will be placed in the buffer, and comes out of the loop buffer after the required amount of delay. The main advantage of this architecture is that no controlling is required inside the buffer. The working of the switch is explained in detail and simulations are done to obtain packet loss probability and delay. These results have been verified by the mathematical model.
Cluster Computing, 2004
Currently, the growth in capacity demand is still increasing by the emergence of a large number of applications that dramatically increase bandwidth demand and generate a large number of resource requirements in the network. Since the emerging applications require increased bandwidth capacity, the vision of using optical technology in the communication channel, signal processing, and switching fabric is very promising. This article presents an overview of optical switching techniques currently under research investigations. It introduces enabling technologies that have been recently researched and then presents some newly proposed architectures. It describes the SKYLIGHT switch that has been recently developed by the author. The architecture design of the switch is based on a optical code division multiple access (OCDMA) technique. Performance evaluation of the switch fabric based on the analytical evaluation of the code and numerical simulations of the optical components used to implement the system is presented.
Revista Científica
Resumo -Apresentam-se aqui novos circuitos para identificação, roteamento e resolução de contenda entre pacotes ópticos com cabeçalho em freqüência, integralmente desenvolvidos em nossos laboratórios. Os tempos de processamento dos circuitos eletrônicos são muito rápidos: os circuitos de reconhecimento de cabeçalho (HRC) e de decisão lógica (LDC) respondem em 40 ns. Ambos circuitos foram construídos usando tecnologia fast TTL. O chaveamento, roteamento e a solução de contenda são realizados pacote-a-pacote sem que haja degradação ou perda de pacotes ópticos. Este sistema é aplicável em chaveamento óptico de pacotes em futuras redes fotonicas transparentes.
IEEE/OSA Journal of Lightwave Technology, 2008
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-toparallel 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 semiconductor optical amplifiers. 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 8 all-optical decoder and a packet envelope detector.
Journal of Optical Networking, 2009
The proposed work presents a new structure that can be used as reconfigurable optical logic gates. This structure is constructed in a two dimensional (2D) photonic crystals (PhCs). Logic gates like AND, NOT and NOR are realized by using the proposed structure. These optical logic gates are constructed in 6 µm * 6 µm in 2D PhCs square lattice with a lattice constant a=0.648 µm. All the gates are realized by creating structural disorders in the cross-waveguide geometries of 2D PhCs. The several performance parameters are examined using this structure and observed that proposed structure has reduced size, fast response time of 0.46ps, high bit rates of 2.14Tbits/sec and better contrast ratio of 8.6dB against the existing designs. The signal amplitude larger than 0.5 arbitrary units (a.u.) and less than 0.1 (a.u.) at output are considered as logic ‘1’ and ‘0’ respectively. The plane wave expansion (PWE) is utilised to get the band gap for this logic gate 2D PhC structure and the finite ...
Selected Topics on Optical Amplifiers in Present Scenario, 2012
Advances in Wireless Technologies and Telecommunication
Optical packet switching is connectionless networking solution through which we can get high speed data transfer and optimum bandwidth utilization using wavelength division multiplexing technique. For realizing optical packet switching the numbers of optical packet switch architectures are available in market. In this chapter the authors discuss the overall development of optical packet switching; some recently published optical packet switch architectures are discussed in the chapter and a comparison is performed between the switches through loss, cost and buffer analysis.
IET Optoelectronics, 2011
All-optical logic device is a vital element in ultra high speed all-optical networks. If the element is programmable then the device become more sophisticated and user friendly. In this study, a compact all-optical programmable Boolean logic unit (PBLU) is proposed using two cascaded semiconductor optical amplifiers on the Mach-Zehnder interferometer arms-based switches. PBLU can perform any of the
Int'l J. of Communications, Network and System Sciences, 2011
Optical Packet Switching (OPS) and transmission networks based on Wavelength Division Multiplexing (WDM) have been increasingly deployed in the Internet infrastructure over the last decade in order to meet the huge increasing demand for bandwidth. Several different technologies have been developed for optical packet switching such as space switches, broadcast-and-select, input buffered switches and output buffered switches. These architectures vary based on several parameters such as the way of optical buffering, the placement of optical buffers, the way of solving the external blocking inherited from switching technologies in general and the components used to implement the WDM. This study surveys most of the exiting optical packet switching architectures. A simulation-based comparison of input buffered and output buffered architectures is presented. The performance analysis of the selected two architectures is derived using simulation program and compared at different scenarios. We found that the output buffered architectures give better performance than input buffered architectures. The simulation results show that the-broadcast-and-select architecture is attractive in terms that it has lees number of components compared to other switches.
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