Optical Data Networks Research Articles

Architecting the services optical network

In this new millennium, the most valuable commodity will be information, as seen by the surge in demand for faster access technologies such as cable modems, xDSL, and wireless data. The tremendous growth in data traffic, particularly that associated with the Internet, is changing the way it is carried over public and private networks. Together with the rapid advances in optical networking technology and the spawning of a new category of wavelength services stimulated by new high-speed data requirements, this is dramatically changing network architectures and the relationship between network service providers and their customers. Incumbent carrier globalization and new carrier entry require support for a broader set of business models and range of service interfaces. The growth and expansion of networks imply a greater need for more scalable solutions and more automation for network maintenance. An intelligent optical core optimized for service optical networking, the services optical network, needs to take the best aspects of both the transport and data networking domains to meet the above needs. This article focuses on architecting the services optical network to meet the challenges of optical data networking, and includes a snapshot of supporting standardization activities.

Analytical calculation of throughput of ALOHA based protocols in optical wireless data networks

An analytical framework for the calculation of the throughput performance of random-access protocols based on ALOHA is presented under blockage conditions in optical wireless data networks. A simple approximate Markovian channel model, which describes the channel variability, is proposed, Based on that, an analytical technique is developed for the calculation of the throughput of S-ALOHA paired with a general backoff-retransmission policy. It is shown that this combination can provide stabilised throughput performance under adverse blockage conditions. Calculation of the throughput for reservation ALOHA under the same channel conditions is described. The analytical techniques described are based on equilibrium-point analysis and their predictions are in very good agreement with Monte-Carlo-simulation results.

On joint protection/restoration in IP-centric DWDM based optical transport networks

Previous advances in WDM technology are now beginning to shift the focus more toward optical networking and network-level issues. Providing survivability at the optical layer is inherently attractive, but whether it makes practical sense, given similar mechanisms that are already available at the higher layers, poses serious challenges and raises many questions. Today's core network architecture model has functional overlap among its layers, contains outdated functionality, and is too slow to scale. If IP can be mapped directly onto the WDM layer, some of the unnecessary network layers can be eliminated, opening up new possibilities for developing a simple and integrated-protection/restoration scheme that can be coordinated at both the IP and WDM layers. This article presents an overview of existing optical protection/restoration schemes. Then we present a novel mesh-based hybrid optical protection scheme that utilizes multifiber physical links along with a hierarchical OXC structure. An overview of the envisioned IP-centric DWDM-based optical data network architecture is then presented. The basis of how to implement a more direct IP standard-based approach for closer and efficient IP-WDM integration is also discussed. Finally, we articulate a view of how to provide a joint protection/restoration scheme that is coordinated at both the IP and WDM layers.

Optical data networking

We challenge current thinking about IP over WDM by outlining a path to optical data networking that includes multiple data networking protocols coupled with a protocol-neutral optical networking infrastructure. Included is a discussion of the diversity of data networking protocols and network architectures for optical data networking.

Optical data networking: protocols, technologies, and architectures for next generation optical transport networks and optical internetworks

We present a high-level but extensive overview of the protocols, technologies, network architectures, and issues and challenges for next-generation optical transport networks and optical internetworks.

Optical Amplifiers in Broadcast Optical Networks: A Survey

Optical data networks are needed to meet ever increasing bandwidth requirements. Broadcast optical networks can provide easy and reliable implementation of optical networks, but due to limited power budget, the number of users supported are limited. The optical amplifiers (OAs) can be used to Increase the number of users supported by the network. In this paper use of semiconductor optical amplifiers (SOAs) and doped fiber amplifier (DFAs) is being surveyed in several broadcast topologies, e.g. bus, star, tree etc.

Architectures and technologies for high-speed optical data networks

Current optical networks are migrating to wavelength division multiplexing (WDM)-based fiber transport between traditional electronic multiplexers/demultiplexers, routers, and switches. Passive optical add-drop WDM networks have emerged but an optical data network that makes full use of the technologies of dynamic optical routing and switching exists only in experimental test-beds. This paper discusses architecture and technology issues for the design of high performance optical data networks with two classes of technologies, WDM and time division multiplexing (TDM). The WDM network architecture presented stresses WDM aware Internet protocol (IP), taking full advantage of optical reconfiguration, optical protection and restoration, traffic grooming to minimize electronics costs, and optical flow-switching for large transactions. Special attention is paid to the access network where innovative approaches to architecture may have a significant cost benefit. In the more distant future, ultrahigh-speed optical TDM networks, operating at single stream data rates of 100 Gb/s, may offer unique advantages over WDM networks. These advantages may include the ability to provide integrated services to high-end users, multiple quality-of-service (QoS) levels, and truly flexible bandwidth-on-demand. The paper gives an overview of an ultrahigh-speed TDM network architecture and describes recent key technology developments such as high-speed sources, switches, buffers, and rate converters.

Nonlinear optic phase conjugation

An overview of the field of nonlinear optical phase conjugation is given. The basic properties of a phase-conjugate mirror are discussed, and examples of how this technology can be applied to the areas of high-power lasers, optical communication systems, and optical data processing (including neural networks) are presented. It is shown that the massively parallel data processing capabilities inherent in nonlinear optical interactions, coupled with their passive, all-optical nature, make this class of system potentially useful for the next generations of advanced laser systems, remote sensors, and communications systems, as well as optical data processors and network systems architectures.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Performance and protocol improvements for very high speed optical fiber local area networks using a passive star topology

Two random-access schemes for a multiuser very-high-speed optical data network based on a star topology are presented and analyzed. The protocols presented do not require any type of carrier sensing, and their performance is independent of a, the normalized propagation time of packets over the optical medium. This property is rather important when dealing with very-high-speed networks which result in high values of a, because the performance of the conventional carrier sensing schemes is poor under such conditions. The protocols outperform the corresponding algorithms of I.M.I. Habbab et al. (1987) for all values of system parameters.

海洋研究船「白鳳丸」の各種システム

“Hakuho Maru” was delivered to the Ocean Research Institute of the University of Tokyo in May, 1989. She is a sophisticated “multi-purpose” oceanographic research vessel, and her tasks are varied in many fields; geology, geophysics, meteorology, physical oceanography, chemistry, biology, and fishery science. In order to achieve these tasks, she is equipped with the following special systems.(1) Electric Propulsion System(2) Machinery Part One Man Control System(3) Joystick Control System(4) Integrated Navigation System(5) Optical Data Network(6) Data Processing SystemThese systems are introduced in this treatice.

FSK with direct detection in optical multiple-access FDM networks

High-performance optical data networks of the future may interconnect hundreds of users at gigabit rates for a reasonable cost. A novel approach is described that utilizes a passive star coupler for distribution, a multiplicity of frequency-shift keyed (FSK) tunable lasers to provide a frequency division multiplexed (FDM) network, and a tunable optical fiber Fabry-Perot filter to select the channels and convert the FSK signal to ASK (amplitude-shift keying) for direct detection. The design of high-speed FDM-FSK direct detection networks and the performance of critical devices, such as tunable FM lasers, tunable filters, integrated star couplers, and optical amplifiers, are reviewed and discussed. >

OPTICAL FIBRE DIGITAL BUS FOR AVIONICS DATA SYSTEMS

In this paper, an optical fibre data network on board of military a/c is considered. Over this network informations are to be communicated between computers, sensors, displays and other avionics systems in form of packetized message. Empty slots strategy protocol is considered over a loop configurated network. Some aspects of this network are analyzed so as to cl arify its traffic characteristics and design issues. A complete experimental set-up is under development. A 3-station loop con-figuration is assumed and interface units for each station is implemented using the commerically available MSI digital circuits. CRT photos showing packetized signals, framing and synchronization signals are included. Imple-mentation using microprocessors will be straight-forward from the implemented scheme.