Photonic switching fabrics
TL;DR: The strengths and limitations of the photonic technology are reviewed, beginning with the temporal bandwidth limitations of photonic devices and then focusing on spatial bandwidth, commonly referred to as the parallelism of optics, and how it can be used in photonic fabrics.
Abstract: The strengths and limitations of the photonic technology are reviewed, beginning with the temporal bandwidth limitations of photonic devices and then focusing on spatial bandwidth, commonly referred to as the parallelism of optics, and how it can be used in photonic fabrics. Some of the proposed photonic switching fabrics that are based on guided-wave devices are discussed, comprising switching fabrics based on space channels, using directional couplers and optical amplifiers, and those based on time channels. The latter include active reconfigurable fabrics based on TDM, time-slot interchangers, and universal time slots, in addition to passive shared media fabrics. Some of the switching fabrics that have been proposed using wavelength channels are outlined, and multidimensional fabrics are briefly reviewed. Photonic switching fabrics based on free-space devices are described, covering free-space relational switching fabrics, the basic hardware required for digital free-space optical fabrics, and digital free-space switching fabrics. >
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TL;DR: Integrated structures that will allow for improvements of current signal-processing functions as well as the implementation of novel device concepts are presented.
Abstract: The authors present a review of all-optical signal-processing technologies based on /spl chi//sup (2)/ nonlinear interactions in guided-wave devices and their applications for telecommunication. In this study, the main focus is on three-wave interactions in annealed proton-exchanged periodically poled lithium niobate waveguides due to their suitable properties with respect to nonlinear mixing efficiency, propagation loss, and ease of fabrication. These devices allow the implementation of advanced all-optical signal-processing functions for next-generation networks with signal bandwidths beyond 1 THz. In this paper, integrated structures that will allow for improvements of current signal-processing functions as well as the implementation of novel device concepts are also presented.
246 citations
01 Dec 1997
TL;DR: In this paper, the basic principles of optical transmission in fiber and reviews the current state of the art in optical device technology are discussed, and various optical components can be incorporated into WDM optical networks for both local and wide-area applications.
Abstract: Recently, there has been growing interest in developing optical fiber networks to support the increasing bandwidth demands of multimedia applications, such as video conferencing and World Wide Web browsing. One technique for accessing the huge bandwidth available in an optical fiber is wavelength-division multiplexing (WDM). Under WDM, the optical fiber bandwidth is divided into a number of nonoverlapping wavelength bands, each of which may be accessed at peak electronic rates by an end user. By utilizing WDM in optical networks, we can achieve link capacities on the order of 50 THz. The success of WDM networks depends heavily on the available optical device technology. This paper is intended as a tutorial on some of the optical device issues in WDM networks. It discusses the basic principles of optical transmission in fiber and reviews the current state of the art in optical device technology. It introduces some of the basic components in WDM networks, discusses various implementations of these components, and provides insights into their capabilities and limitations. Then, this paper demonstrates how various optical components can be incorporated into WDM optical networks for both local and wide-area applications. Finally, the paper provides a brief review of experimental WDM networks that have been implemented.
213 citations
01 Jan 1989
TL;DR: The symmetric self-electrooptic effect device (S-SEED) as discussed by the authors is an optically bistable set-reset latch with two p-i-n diodes connected in series.
Abstract: The symmetric self-electrooptic-effect device (S-SEED), a structure consisting of two p-i-n diodes electrically connected in series and acting as an optically bistable set-reset latch, is discussed. Applications and extensions of this device are also discussed. The devices do not require the critical biasing that is common to most optically bistable devices and thus is more useful for system applications. They have been optically cascaded in a photonic ring counter and have been used to perform different NOR, OR, NAND, and AND logic functions. Using the same device, a differential modulator that generates a set of complementary output beams with a single voltage control lead and a differential detector that gives an output voltage dependent on the ratio of the two optical input powers have been demonstrated. >
205 citations
TL;DR: This work presents the disjoint alternate path (DAP) algorithm which places optical channels in order to maximize design protection and shows the result on various network examples.
Abstract: With wavelength division multiplexing (WDM) networks the failure of a single link or component may cause the simultaneous failure of several optical channels, potentially making impossible restoration by rerouting directly in higher layers directly using the optical network (SDH, ATM, internal protocol (IP)). To address this, we introduce the concept of design protection, which aims at making such failure propagations impossible. We present the disjoint alternate path (DAP) algorithm which places optical channels in order to maximize design protection. We show the result on various network examples.
176 citations
28 Jul 2008
TL;DR: The demographic data leads the discussion to (1) radio-on-fiber access network architecture as green networks and (2) thin client models as the key to sustain the evolution toward the future.
Abstract: This paper describes energy consumption demographic data in operating real mobile networks. We examine published data from NTT DoCoMo, which is the largest mobile telecommunication operator in Japan and operating nationwide 3G networks, and identify the most power consuming part is of radio access networks including base tranciever stations. We also investigate power consumption of terminals, and find that the consumption ratio of terminal v.s. networks is about 1:150. Our daily energy consumption per a customer is 0.83 Wh/day for a terminal and 120 Wh/day for the mobile network. The terminal side energy consumption is negligible in view of total CO2 emission though, limitation of its battery performance raises another issue called "energy starvation of mobile devices." The demographic data leads our discussion to (1) radio-on-fiber access network architecture as green networks and (2) thin client models as the key to sustain the evolution toward the future.
163 citations
Cites background from "Photonic switching fabrics"
...In [6], it is shown that the power per bit required to switch the state of a semiconductor device is more than 10(2) to 10(3) higher than that of a photonic device....
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References
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TL;DR: In this paper, a water-cooled integral heat sink for silicon integrated circuits has been designed and tested at a power density of 790 W/cm2, with a maximum substrate temperature rise of 71°C above the input water temperature.
Abstract: The problem of achieving compact, high-performance forced liquid cooling of planar integrated circuits has been investigated. The convective heat-transfer coefficient h between the substrate and the coolant was found to be the primary impediment to achieving low thermal resistance. For laminar flow in confined channels, h scales inversely with channel width, making microscopic channels desirable. The coolant viscosity determines the minimum practical channel width. The use of high-aspect ratio channels to increase surface area will, to an extent, further reduce thermal resistance. Based on these considerations, a new, very compact, water-cooled integral heat sink for silicon integrated circuits has been designed and tested. At a power density of 790 W/cm2, a maximum substrate temperature rise of 71°C above the input water temperature was measured, in good agreement with theory. By allowing such high power densities, the heat sink may greatly enhance the feasibility of ultrahigh-speed VLSI circuits.
4,214 citations
30 Apr 1968
TL;DR: To achieve high throughput rates today's computers perform several operations simultaneously; not only are I/O operations performed concurrently with computing, but also, in multiprocessors, several computing operations are done concurrently.
Abstract: To achieve high throughput rates today's computers perform several operations simultaneously. Not only are I/O operations performed concurrently with computing, but also, in multiprocessors, several computing operations are done concurrently. A major problem in the design of such a computing system is the connecting together of the various parts of the system (the I/O devices, memories, processing units, etc.) in such a way that all the required data transfers can be accommodated. One common scheme is a high-speed bus which is time-shared by the various parts; speed of available hardware limits this scheme. Another scheme is a cross-bar switch or matrix; limiting factors here are the amount of hardware (an m × n matrix requires m × n cross-points) and the fan-in and fan-out of the hardware.
2,553 citations
TL;DR: Given a vector of N elements, the perfect shuffle of this vector is a permutation of the elements that are identical to aperfect shuffle of a deck of cards.
Abstract: Given a vector of N elements, the perfect shuffle of this vector is a permutation of the elements that are identical to a perfect shuffle of a deck of cards. Elements of the first half of the vector are interlaced with elements of the second half in the perfect shuffle of the vector.
1,331 citations
TL;DR: A baseline network and a configuration concept are introduced to evaluate relationships among some proposed multistage interconnection networks and it is proven that the data manipulator, flip network, omega network, indirect binary n-cube network, and regular SW banyan network are topologically equivalent.
Abstract: A baseline network and a configuration concept are introduced to evaluate relationships among some proposed multistage interconnection networks. It is proven that the data manipulator (modified version), flip network, omega network, indirect binary n-cube network, and regular SW banyan network (S = F = 2) are topologically equivalent. The configuration concept facilitates developing a homogeneous routing algorithm which allows one-to-one and one- to-many connections from an arbitrary side of a network to the other side. This routing algorithm is extended to full communication which allows connections between terminals on the same side of a network. A conflict resolution scheme is also included. Some practical implications of our results are presented for further research.
799 citations
Abstract: Spread spectrum code division multiple access (CDMA) allows asynchronous multiple access to a local area network (LAN) with no waiting. The additional bandwidth required by spread spectrum can be accommodated by using a fiber-optic channel and incoherent optical signal processing. New CDMA sequences are designed specifically for optical processing. It is shown that increasing the number of chips per bit, by using optical processing, allows an increase in capacity of a CDMA LAN. An experiment is performed demonstrating the performance of an optical CDMA LAN, operating at 100 Mbd with three users.
768 citations