Arrays of optoelectronic switching nodes comprised of flip-chip-bonded MQW modulators and detectors on silicon CMOS circuitry

We describe 8/spl times/8 arrays of smart pixels, designed and fabricated using MQW modulators and detectors flip-chip-solder-bonded to silicon CMOS circuits. The individual circuits implement 2 input, 1 output embedded control switching nodes. Four arrays from two different designs were fabricated and tested. For the array with the highest yield, 60 of 64 nodes functioned correctly at low speeds and were tested up to 250 Mb/s without re-adjusting individual bias voltages with the maximum speed of an individual node of 375 Mb/s. For the second-generation array, the center 4/spl times/8 section of the array was tested at data rates beyond 700 Mb/s with individual nodes having short term bit error rates below 10-/sup 11/.     

A high-speed four-channel subscriber fibre-optic link for broadband networks

This paper describes the performance of a 560 Mb/s digital fibre-optic link designed specifically for possible use in a broadband integrated services digital network (BISDN) environment. Four 140 Mb/s non-return-to-zero (NRZ) channels are time division multiplexed using a bit-by-bit multiplexing strategy and transmitted using potentially low cost 1.3 μm EE-LED and laser sources. A 10^?9 bit error rate with a power level of -34 dBm was achieved for each independent channel over a distance of 10 km.     

Wideband packet technology in the integrated access and cross-connect system (IACS)

The integrated access and cross-connect system (IACS) is an AT&T product based on the wideband packet technology. The IACS has two components: the integrated access terminal (IAT) and the integrated access controller (IAC). The IAC provides centralized control, operations and maintenance for a network of IATs. An IAT provides direct digital connectivity at 1·536 Mb/s or 2·048 Mb/s to customer terminals and to circuit- and packet-switched networks. It integrates voice, voiceband data, facsimile traffic, digital data, signalling, image and network control into packets of common format. It allows networking in both the circuit and packet domains, offers bandwidth on demand, and achieves graceful degradation of voice quality during congestion.     

The DTX-240D digital circuit multiplication system

This paper describes the DTX-240D digital circuit multiplication system (DCMS) offered by ECI Telecom. It will accept up to 240 × 64 kb/s trunks carrying either 64 kb/s voice, voice band analogue non-speech signals, or digital data for transmission over a 2·048 Mb/s digital link. Over 1000 are currently ‘on-line’ and carrying traffic. The system comprises a pair of terminals, one on each side of the interterminal digital link (bearer). It will normally operate in the network at a concentration ratio of 5:1, in which case 150 × 64 kb/s trunks, carrying voice, voice band data or digital data can be concentrated into one 2·048 Mb/s bearer. The users are able to increase the number of trunks up to 240 per 2·048 Mb/s bearer, when time zone differences cause a spread of busy-hour traffic carried on a single system. Each terminal will normally be located at an international switching centre (ISC) but may also be located at an earth-station. The system uses a DSI (digital speech interpolation) stage providing a 2·5:1 multiplication, followed by an additional 2:1 multiplication by means of ADPCM (adaptive differential pulse code modulation). In addition, the VBR (variable bit rate) technique is used to prevent clipping, due to overload congestion. The system can also be used with 1·544 Mb/s digital bit streams (trunk side or bearer).     

Digital optical CATV system using hubbed distribution architecture

A hubbed distribution architecture based on a bus-star configuration, three-level single single-mode fiber transmission using M-TPC line code, and high-speed IC technology is proposed. The architecture is cost-effective and compact. It is well suited to metropolitan area CATV systems and would allow a gradual transition to a broadband ISDN (integrated-services digital network) subscriber loop in the future. The proposed architecture is applied to a digital optical CATV system prototype. The equipment making up this system consists of a transmitter, hubs including video selectors, and subscriber unit. Two video channels are selected for each subscriber from eight video channels at hub stations. The transmission speed is 900 Mb/s, three-level for the trunk line and 200 Mb/s, three-level for each subscriber loop. Very compact and low-cost equipment is realized by using recently developed high-speed ICs. Experimental results show that the system satisfies requirements and that its commercial application is feasible     

Fiber-optic digital video distribution system for usinghigh-definition television signals using laser-diode optical switch

A fiber-optic high-definition television (HDTV) distribution system is discussed, which economically distributes HDTV signals to customers at a bit rate of about 100 Mb/s. The subscriber network is formed in a star topology to facilitate bidirectional connection. The distribution system uses digital video transmission at 1.3 μm wavelength using single-mode fiber. The video channel selection is made by an optical video selector. The optical selector consists of laser diode optical switch modules, which have a gain in the `ON' state and two-input, two-output 3 dB couplers. The authors describe the bit error rate characteristics of a signal-mode fiber digital distribution system using a four-input, one-output optical selector     

Regenerator chip set for high-speed digital transmission

The authors have developed a custom two-chip set containing all of the active circuitry necessary for regeneration of digital electrical signals in a 300-Mb/s fiber-optic transmission system. The set includes an automatic gain control (AGC) amplifier with gain-bandwidth product in excess of 100 GHz, and a decision circuit with excellent dynamic sensitivity, measured up to 650 Mb/s. The chips are fabricated using a 2.5-/spl mu/m fully complementary bipolar process.     

A Low-Power Digital IC Design Inside the Wireless Endoscopic Capsule

This paper proposes an architecture of the wireless endoscopy system for the diagnoses of whole human digestive tract and real-time endoscopic image monitoring. The low-power digital IC design inside the wireless endoscopic capsule is discussed in detail. A very large scale integration (VLSI) architecture of three-stage clock management is applied, which can save 46% power inside the capsule compared with the design without such a low-power design. A stoppable ring crystal oscillator with minimal overhead is used in the sleep mode, which results in about 60-muW system power dissipation in sleep mode. A new image compression algorithm based on Bayer image format and its corresponding VLSI architecture are both proposed for low-power, high-data volume. Thus, 8 frames per second with 320*288 pixels can be transmitted with 2 Mb/s. The digital IC design also assures that the capsule has many flexible and useful functions for clinical application. The digital circuits were verified on field-programmable gate arrays and have been implemented in 0.18-mum CMOS process with 6.2 mW     

Error and flow control performance of a high speed protocol

The performance of the SNR protocol of A. N. Netravali et al. (1990) is studied when it is implemented for end-to-end flow and error control. Using a combination of analysis and simulation, the efficiency with which this protocol uses the network bandwidth and its achievable throughput is evaluated as a function of certain network and protocol parameters. The protocol is enhanced by introducing two windows to decouple the two functions of receiver flow control and network congestion control. This enhancement and the original protocol are compared with go-back-N (GBN) and one-at-a-time-selective-repeat (OSR) retransmission procedures, are shown to have significantly higher throughput for a wide range of network conditions. As an example, for a virtual circuit with 60-ms roundtrip delay and 10^-8 bit error rate, in order to deliver 500 Mb/s throughput, both the GBN and OSR require a raw transmission bandwidth of approximately 800 Mb/s, whereas SNR with two windows needs slightly higher than 500 Mb/s raw bandwidth. Periodic exchange of state can also provide a variety of measures for congestion control in a timely and accurate fashion     

电缆调制-解调器的技术进展

首先说明传统电话网为了适应数据通信需要 ,在用户线上设置调制 -解调器 ,传送数据速率达5 0～ 6 0 kb/ s,又为了用户能够接入 Internet索取大量数据信息 ,在不对称数字用户线上设置调制 -解调器 ,在下行方向提供较高数据速率 1.5～ 9.0 Mb/ s。着重地介绍由光纤和同轴电缆混合组成的有线电视网 CATV,以及它除了广播电视信号外 ,还设置电缆调制 -解调器 cable modem,以便电视台与用户间能够互通电话和数据通信 ,并让用户接入 Internet索取信息 ,其数据速率高达 10～ 30 Mb/ s。     

铜芯对绞电缆新的发展和应用

在信息高度发达的今天，计算机网络成为连接全球的电子纽带。当网络速度从早期的10Mb/s发展到1000Mb/s，综合布线系统，这一计算机网络的传输平台也发展为一个巨大的市场。随着高速计算机网络系统的兴起，综合布线正在进入一个新的时期。     

Application-layer multicasting with Delaunay triangulation overlays

Application-layer multicast supports group applications without the need for a network-layer multicast protocol. Here, applications arrange themselves in a logical overlay network and transfer data within the overlay. We present an application-layer multicast solution that uses a Delaunay triangulation as an overlay network topology. An advantage of using a Delaunay triangulation is that it allows each application to locally derive next-hop routing information without requiring a routing protocol in the overlay. A disadvantage of using a Delaunay triangulation is that the mapping of the overlay to the network topology at the network and data link layer may be suboptimal. We present a protocol, called Delaunay triangulation (DT protocol), which constructs Delaunay triangulation overlay networks. We present measurement experiments of the DT protocol for overlay networks with up to 10 000 members, that are running on a local PC cluster with 100 Linux PCs. The results show that the protocol stabilizes quickly, e.g., an overlay network with 10 000 nodes can be built in just over 30 s. The traffic measurements indicate that the average overhead of a node is only a few kilobits per second if the overlay network is in a steady state. Results of throughput experiments of multicast transmissions (using TCP unicast connections between neighbors in the overlay network) show an achievable throughput of approximately 15 Mb/s in an overlay with 100 nodes and 2 Mb/s in an overlay with 1000 nodes.     

A monolithic 480 Mb/s parallel AGG/decision/clock-recovery circuitin 1.2-μm CMOS

A parallel architecture for high-data-rate AGC/decision/clock-recovery circuit, recovering digital NRZ data in optical-fiber receivers, is described. Improvement over traditional architecture in throughput is achieved through the use of parallel signal paths. An experimental prototype, fabricated in a 1.2-μm double-poly double-metal n-well CMOS process, achieves a maximum bit rate of 480 Mb/s. The chip contains variable gain amplifiers, clock recovery, and demultiplexing circuits. It yields a BER of 10^-11 with an 18 mV_p-p differential input signal. The power consumption is 900 mW from a single 5 V supply     

A 20-channel optical communication system using subcarriermultiplexing for the transmission of digital video signals

Microwave subcarriers have been used to demonstrate an optical communication system suitable for the distribution of digital video channels. The design, performance, and optical link requirements are discussed for a 2-Gb/s subcarrier-multiplexed (SCM) system with 20 microwave subcarriers modulated at 100 Mb/s and using a frequency-shift-keyed format. The system uses the 2-6-GHz bandwidth and represents the first example of an SCM system using more than one octave of bandwidth. The bit error rate was measured for all 20 channels; results for five typical channels are shown and discussed. The performance results show that a digital SCM approach is attractive in an optical link for a multichannel wide bandwidth video distribution system made from standard microwave components     

NMOS multiplexer for fiber optics

The design, layout, and testing of a 5 Mb/s digital multiplexer using 2-/spl mu/m design rules for fiber-optic applications are described. Using a common 10-bit bus, the chip reads data from 16 sources in response to a DATA READY signal. Serial output includes a parity bit and is sent to an LED driver. Handshaking, sequential control, parity checking, and data formatting are covered.     

Packet communication protocol for image services on a high-speedmultimedia LAN

The authors describe the requirements for high-speed multimedia communication and propose a high-speed communication protocol to provide congestion-free access and efficient retransmission/flow control. Its usefulness is proved in a 400 Mb/s multiaccess loop local area network (LAN) with a 100 Mb/s user interface. The main characteristics of the protocol are separation of image communication handling, guarantee of no buffer overflow in a network, and end-to-end block-based transfer. Buffer reservation control in the user-network interface and a retransmission scheme based on a long-size block are used to realize high-speed congestion control and error recovery. A multimedia terminal architecture suitable for real-time image communication is also discussed. In the prototype system, a few frames of high-resolution image information can be transferred in a second. Around 26 Mb/s effective throughput between application entities has been obtained     

Fiber-to-the-home services based on wavelength-division-multiplexing passive optical network

It is anticipated that more than 75 Mb/s per subscriber is required for the convergence service such as triple-play service (TPS). Among several types of high-speed access network technologies, wavelength-division-multiplexing passive optical network (WDM-PON) is the most favorable for the required bandwidth in the near future. Furthermore, WDM technologies, such as athermal arrayed-waveguide grating (AWG) and low-cost light source, have matured enough to be applied in the access network. In this paper, the authors propose and implement a WDM-PON system as a platform for TPS. The system employs an amplified spontaneous emission (ASE)-injected Fabry-Pe/spl acute/rot laser diode scheme. It has 32 channels of 125 Mb/s and adopts Ethernet as Layer 2. Multicast and virtual local area network features are used for the integration of services such as Internet protocol high-definition broadcast, voice-over Internet protocol, video on demand, and video telephone. The services were demonstrated using the WDM-PON system.     

100BASE-T2: a new standard for 100 Mb/s Ethernet transmission overvoice-grade cables

100BASE-T2 is a new physical-layer specification for IEEE 802.3 LANs operating at 100 Mb/s (“Fast Ethernet”). It enables users of the prevailing 10BASE-T Ethernet LAN technology to upgrade their networks from 10 to 100 Mb/s performance while retaining an existing voice-grade cabling infrastructure. 100BASE-T2 transceivers will operate over two pairs in unshielded twisted-pair cables corresponding to EIA/TIA category 3 (UTP-3), as minimally required for 10BASE-T. In a four-pair UTP-3 cable, simultaneous operation of two 100BASE-T2 links, or one 100BASE-T2 and one 10BASE-T link, is permitted. Since voice-grade cables exhibit more signal attenuation and significantly higher crosstalk coupling between adjacent pairs than data-grade cables, sophisticated digital signal processing techniques are needed to achieve reliable duplex 100 Mb/s transmission over two pairs. The 100BASE-T2 standard defines dual-duplex baseband transmission at a modulation rate of 25 Mbaud. During each modulation interval, a four-bit data nibble or Ethernet-specific control information is encoded into a pair of quinary signals. These signals are transmitted simultaneously on the two wire pairs in both signaling directions. In the receivers, adaptive digital filters are required for echo and NEXT cancellation, equalization, and interference suppression     

TRANSMISSION CAPABILITY OF DISCRETE MULTITONE MODULATION FOR TAIWAN’S SUBSCRIBER LOOPS

The transmission of 1.5 Mb/s and beyond data rate in the conventional twisted-pair local loops, called asymmetrical digital subscriber line (ADSL) technology, will be possible to create a new transport access capability to provide economic wideband voice/data/video integrated services directly to residential customers. The term ‘asymmetric’ in ADSL refers to the much higher data rate in the direction from central office (CO) to the customer and the lower rate of return (control) data from the customer to the CO. Discrete multitone (DMT) modulation has been selected as the modulation scheme in ADSL. Because the crosstalk of local loops in Taiwan is 10–15 dB worse than that in the US, the service capability of DMT ADSL for Taiwan’s local loops may be different from that in other countries, and thus needs to be evaluated. On the basis of the characteristics of Taiwan’s local loops, transmission capability is estimated to be 1.544 Mb/s and 6 Mb/s in Taiwan. Simulation results also show what percentage of users in Taiwan may have 1.544 Mb/s or 6 Mb/s of ADSL services. Far-end crosstalk (FEXT) and additive white Gaussian noise (AWGN) are considered to be the dominant noise sources in the work.     

Performance evaluation of a picture archiving and communication network using stochastic activity networks

A fiber-optic star-based picture archiving and communication system (PACS) network that is based on a multiplexed passive star local area network with wavelength-division multiplexing (WDM) to provide separate logical channels for transfer of control and image data is discussed. The system consists of an image network (INET), for image transfer at a rate of 140 Mb/s, and a control network (CNET), operating at 10 Mb/s, for mediating the flow of image transfers. INET is a circuit switched network devoted solely to image transfer, while CNET employs the CSMA/CD protocol for bus arbitration. Stochastic activity networks were used to develop a detailed model of the command and image channels. The performance of the system was then evaluated under realistic workload conditions. In particular, a number of important performance variables, including the image response time, command channel delay, and queue length at each type of node and the network supervisor, are estimated. The results (1) show that stochastic activity networks are an appropriate model type for evaluating picture archiving and communication systems, (2) delineate the workload conditions under which PACS may effectively operate, and (3) show that even when these conditions are exceeded, the command channel load remains extremely light.