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ABSTRACT The feasibility of transmitting 1 55-Mb/s SONET/ATM signals over 131 m of unshielded 24 AWG single twisted pair copper cable and 213 m of shielded 22 AWG twisted pair cable with bit error ratios of less than 10 -13 is shown. The... more
ABSTRACT The feasibility of transmitting 1 55-Mb/s SONET/ATM signals over 131 m of unshielded 24 AWG single twisted pair copper cable and 213 m of shielded 22 AWG twisted pair cable with bit error ratios of less than 10 -13 is shown. The transmission performance of the single-pair unshielded cable is compared to that of category 3 and 5 four-pair unshielded twisted pair cables and category 1 two-pair shielded twisted pair cables. The merits of two-level encoding and three-level encoding are examined. The three-level encoding has a noise margin that is 6 dB greater than the two-level encoding. The results indicate that it may be feasible to employ copper drops for distribution of SONET/ATM asynchronous optical network/asynchronous transfer mode) signals to businesses and residences and for a local area network within an office complex
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ABSTRACT Future communications networks will be required to provide the switching of very broad-band digita'' channels (typically 155. 52 Mb/s or higher) for as many as 60 customers. Power consumption and cable management... more
ABSTRACT Future communications networks will be required to provide the switching of very broad-band digita'' channels (typically 155. 52 Mb/s or higher) for as many as 60 customers. Power consumption and cable management are a major factor in the systems level design considerations. It is shown that through the use of ultra-low threshold laser diode arrays optical fiber ribbon cables and a thoughtful packaging strategy significant electrical power advantage can be accrued over conventional electrical interconnection approaches. 1_a
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Wavelength Division Multiplexing (WDM) techrlology is being considered for emerging telecommunications and data networks, with the first likely deployment in interoffice applications. WDM allows several overlay networks on one physical... more
Wavelength Division Multiplexing (WDM) techrlology is being considered for emerging telecommunications and data networks, with the first likely deployment in interoffice applications. WDM allows several overlay networks on one physical network, and offers the ability to increase the network capacity and flexibility without additional investment in fiber optic infrastnrcture. Advances such as optical amplifiers and WDM crossconnects enable network implementations in a scalable and modular manner. Although WDM may offer advantages from a physical transmission and switching perspective, it becomes increasingly clear that methods for operations and management of WDM networks need to be defined. The fact that WDM networks can support a large variety of signal formats transparently through network nodes poses serious concerns about the ability to manage, controt and operate these networks. Timely commercialization of WDM networks requires a criiical assessment of how new WDM technologies and architectures might affect network operations and how network operations might influence the design of the WDM components.
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Two approaches to achieving transmission capacities of 20 Gbit/s that are currently being supported in various network testbeds are a) expanding the SONET/SDH transmission hierarchy to the OC-192 (9.953 Gb/s) data rate and b) using... more
Two approaches to achieving transmission capacities of 20 Gbit/s that are currently being supported in various network testbeds are a) expanding the SONET/SDH transmission hierarchy to the OC-192 (9.953 Gb/s) data rate and b) using wavelength division multiplexing techniques. The former approach offers the potential to upgrade existing optical fiber facilities and to use transmission protocols and operations procedures that are already familiar to the data communications community. One of the most significant advantages to OC-192 systems is the potential to reduce network implementation and operations costs.
Research Interests: Physics and Optical fiber
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A focused argon‐ion laser beam (λ=350 nm) is used to fabricate optical channel waveguides on oxidized silicon wafers using a commerically available spin‐on polymer. The polymerization process is photon induced, thus allowing the reaction... more
A focused argon‐ion laser beam (λ=350 nm) is used to fabricate optical channel waveguides on oxidized silicon wafers using a commerically available spin‐on polymer. The polymerization process is photon induced, thus allowing the reaction to occur in a room‐temperature ambient. This allows the fabrication of waveguides on a variety of substrates including those with low melting points. The losses in these waveguides are typically less then 1 dB/cm, making them applicable to a variety of optical interconnect problems. In particular, we demonstrate their use in the fabrication of an optical power tap.
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The implementation of a highly integrated experimental research prototype ATM/SONET interface that operates at the SONET OC-3 rate of 155.52 Mbit/s is reported. The prototype interface provides various features of the physical (SONET) and... more
The implementation of a highly integrated experimental research prototype ATM/SONET interface that operates at the SONET OC-3 rate of 155.52 Mbit/s is reported. The prototype interface provides various features of the physical (SONET) and asynchronous transfer mode (ATM) layers of the B-ISDN protocol reference model. This type of interface could be used in applications such as workstation interfaces in a switched ATM local area network or for the user-network interface in a broadband public network or customer premises network.
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Research Interests:
This demonstration illustrates how a comprehensive database reconciliation tool can provide the ability to characterize data-quality and data-reconciliation issues in complex real-world applications. Telcordia's... more
This demonstration illustrates how a comprehensive database reconciliation tool can provide the ability to characterize data-quality and data-reconciliation issues in complex real-world applications. Telcordia's data reconciliation and data quality analysis tool includes rapid generation of appropriate pre-processing and matching rules applied to a training set created from samples of the data. Once tuned, the appropriate rules can be applied efficiently to the complete data sets. The tool uses a modular Java-based architecture that allows for customized matching functions and iterative runs that build upon previously learned information. It has been applied to several real database reconciliation problems. Telcordia has been able to provide significant insights to clients who recognize that they have data reconciliation problems but cannot determine root causes effectively using currently available off-the-shelf tools. A description of the analysis of a duplicate- record problem in a set of taxpayer databases is included in this report to illustrate the effective use of the tool.
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This demonstration illustrates how a comprehensive database reconciliation tool can provide the ability to characterize data-quality and data-reconciliation issues in complex real-world applications. Telcordia's data reconciliation... more
This demonstration illustrates how a comprehensive database reconciliation tool can provide the ability to characterize data-quality and data-reconciliation issues in complex real-world applications. Telcordia's data reconciliation and data quality analysis tool includes rapid ...
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The device requirements and system design issues for board-level optical links differ from their counterparts in optical links used for longer distance communications. We have fabricated a research prototype of a board-level optical link... more
The device requirements and system design issues for board-level optical links differ from their counterparts in optical links used for longer distance communications. We have fabricated a research prototype of a board-level optical link which is designed to operate in a high-speed digital equipment internal interconnect environment. The experimental transmitter and receiver packages are specifically designed for subminiaturized applications. We have explored the use of photolithographically patterned waveguides made of polymers as an alternative to the use of fiber at the board level. The major aspects of the device design are reviewed, but the emphasis of this paper is the systems-level design issues. We will discuss the design goals and the performance of the link. The results of this work demonstrate the feasibility of optics for signal distribution at the board level.
Research Interests: Engineering and Photonics
ABSTRACT The feasibility is demonstrated of transmitting 155 Mbit/s SONET-ATM signals over 131 m of unshielded 24 AWG single twisted pair copper cable and 213 m of shielded 22 AWG twisted pair cable with bit error ratios of less than... more
ABSTRACT The feasibility is demonstrated of transmitting 155 Mbit/s SONET-ATM signals over 131 m of unshielded 24 AWG single twisted pair copper cable and 213 m of shielded 22 AWG twisted pair cable with bit error ratios of less than 10-13. The transmission performance of the single-pair unshielded cable is compared with that of four-pair unshielded twisted pair cables.
Research Interests:
ABSTRACT We have fabricated acrylic based optical channel waveguides using proximity photolithography as well as laser direct writing. The cladding layer is a photosensitive aliphatic urethane dimethacrylate and the guiding layer is a... more
ABSTRACT We have fabricated acrylic based optical channel waveguides using proximity photolithography as well as laser direct writing. The cladding layer is a photosensitive aliphatic urethane dimethacrylate and the guiding layer is a photosensitive aromatic ...
Two approaches to achieving transmission capacities of 20 Gbit/s that are currently being supported in various network testbeds are a) expanding the SONET/SDH transmission hierarchy to the OC-192 (9.953 Gb/s) data rate and b) using... more
Two approaches to achieving transmission capacities of 20 Gbit/s that are currently being supported in various network testbeds are a) expanding the SONET/SDH transmission hierarchy to the OC-192 (9.953 Gb/s) data rate and b) using wavelength division multiplexing techniques. The former approach offers the potential to upgrade existing optical fiber facilities and to use transmission protocols and operations procedures that are already familiar to the data communications community. One of the most significant advantages to OC-192 systems is the potential to reduce network implementation and operations costs
Research Interests:
Research Interests:
Research Interests:
ABSTRACT The feasibility is demonstrated of transmitting 155 Mbit/s SONET-ATM signals over 131 m of unshielded 24 AWG single twisted pair copper cable and 213 m of shielded 22 AWG twisted pair cable with bit error ratios of less than... more
ABSTRACT The feasibility is demonstrated of transmitting 155 Mbit/s SONET-ATM signals over 131 m of unshielded 24 AWG single twisted pair copper cable and 213 m of shielded 22 AWG twisted pair cable with bit error ratios of less than 10-13. The transmission performance of the single-pair unshielded cable is compared with that of four-pair unshielded twisted pair cables.
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The authors examine several issues associated with the physical design of the very-high-throughput (terabit per second) packet switching systems that will be needed to provide ubiquitous broadband services. It is shown that conventional... more
The authors examine several issues associated with the physical design of the very-high-throughput (terabit per second) packet switching systems that will be needed to provide ubiquitous broadband services. It is shown that conventional physical design alternatives do not scale well to the high data rates and complex connectivity needed to implement these systems. In particular, conventional interconnection technology alternatives, especially at the backplane level, do not provide adequate intramodule connectivity at the required data rates. An alternative design that uses a three-dimensional architecture is proposed. It provides rich connectivity among the switch functions but requires a anew generation of packaging hardware. The power delivery, thermal management, and other important issues that must be addressed before these large broadband switching systems can be realized are discussed
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Research Interests:
The feasibility of transmitting 1 55-Mb/s SONET/ATM signals over 131 m of unshielded 24 AWG single twisted pair copper cable and 213 m of shielded 22 AWG twisted pair cable with bit error ratios of less than 10 -13 is shown. The... more
The feasibility of transmitting 1 55-Mb/s SONET/ATM signals over 131 m of unshielded 24 AWG single twisted pair copper cable and 213 m of shielded 22 AWG twisted pair cable with bit error ratios of less than 10 -13 is shown. The transmission performance of the single-pair unshielded cable is compared to that of category 3 and 5 four-pair unshielded twisted pair cables and category 1 two-pair shielded twisted pair cables. The merits of two-level encoding and three-level encoding are examined. The three-level encoding has a noise margin that is 6 dB greater than the two-level encoding. The results indicate that it may be feasible to employ copper drops for distribution of SONET/ATM asynchronous optical network/asynchronous transfer mode) signals to businesses and residences and for a local area network within an office complex
The implementation of an experimental OC-12/STS-3c/ATM transmission interface for use in the AURORA Gigabit Testbed is described. This interface maps four streams of asynchronous transfer mode (ATM) cell data from network switch nodes and... more
The implementation of an experimental OC-12/STS-3c/ATM transmission interface for use in the AURORA Gigabit Testbed is described. This interface maps four streams of asynchronous transfer mode (ATM) cell data from network switch nodes and computer hosts into the Synchronous Optical Network (SONET) STS-3c transmission format and multiplexes these channels onto a single OC-12 (622 Mb/s) optical signal for transmission to remote network nodes. The interface also performs the reverse demultiplexing functions. It has been tested in both a stand-alone configuration and in one of its intended applications, as an element in an interface between a workstation and an OC-12 ATM/SONET network. This application represents the first known demonstration of a 622-Mb/s ATM workstation interface
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Assessing and improving the quality of data stored in information systems are both important and difficult tasks. For an increasing number of companies that rely on information as one of their most important assets, enforcing high data... more
Assessing and improving the quality of data stored in information systems are both important and difficult tasks. For an increasing number of companies that rely on information as one of their most important assets, enforcing high data quality levels represents a strategic investment aimed at preserving the value of those assets. For a public administration or a government, good data quality translates into good service and good relationships with the citizens. Achieving high quality standards, however, is a major task because of the variety of ways that errors might be introduced in a system, and the difficulty of correcting them in a systematic way. Problems with data quality tend to fall into two categories. The first category is related to inconsistency among systems such as format, syntax and semantic inconsistencies. The second category is related to inconsistency with reality as it is exemplified by missing, obsolete and incorrect data values and outliers. In this paper, we describe a real-life case study on assessing and improving the quality of the data in the Italian Public Administration. The domain of study is set on taxpayer's data maintained by the Italian Ministry of Finances. In this context, we provide the Administration with a quantitative reckoning of such specific problems as record duplication and address mismatch and obsolescence, we suggest a set of guidelines for setting precise quality improvement goals, and we illustrate analysis techniques for achieving those goals. Our guidelines emphasize the importance of data flow analysis and of the definition of measurable quality indicators. The quality indicators that we propose are generic and can be used to describe a variety of data quality problems, thus representing a possible reference framework for practitioners. Finally, we investigate ways to partially automate the analysis of the causes for poor data quality.
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The authors describe an approach which increases package assembly alignment tolerances substantially while demonstrating coupling efficiencies as high as 40%. This has been accomplished by utilizing a spherical lens to couple from the... more
The authors describe an approach which increases package assembly alignment tolerances substantially while demonstrating coupling efficiencies as high as 40%. This has been accomplished by utilizing a spherical lens to couple from the device into single-mode fiber. The ball lens is mounted directly on the chip carrier for maximum thermal and mechanical stability and is aligned mechanically rather than actively. The single-mode fiber alignment is done actively, and the fiber is positioned so as to compensate for misalignments of the ball lens. Coupling to the single-mode fiber was done directly and by using a second lens affixed to the end of the fiber. In addition to relaxed alignment tolerances, this coupling scheme has other advantages. The working distance between the ball lens and single-mode fiber is typically ≈2-4 mm. This allows for easy insertion of microoptical components such as optical isolators or filters into the package. The scheme also lends itself to a flexible, modular approach to packaging. The dual-lens coupling technique has been used to package optical amplifiers. A fiber-to-fiber gain as large as 10 dB has been demonstrated using this coupling technique
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Future communications networks will be required to provide the switching of very broad-band digita'' channels (typically 155. 52 Mb/s or higher) for as many as 60 customers. Power consumption and cable management are a major factor in the... more
Future communications networks will be required to provide the switching of very broad-band digita'' channels (typically 155. 52 Mb/s or higher) for as many as 60 customers. Power consumption and cable management are a major factor in the systems level design considerations. It is shown that through the use of ultra-low threshold laser diode arrays optical fiber ribbon cables and a thoughtful packaging strategy significant electrical power advantage can be accrued over conventional electrical interconnection approaches. 1_a
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A focused argon-ion laser beam (λ=350 nm) is used to fabricate optical channel waveguides on oxidized silicon wafers using a commerically available spin-on polymer. The polymerization process is photon induced, thus allowing the reaction... more
A focused argon-ion laser beam (λ=350 nm) is used to fabricate optical channel waveguides on oxidized silicon wafers using a commerically available spin-on polymer. The polymerization process is photon induced, thus allowing the reaction to occur in a room-temperature ambient. This allows the fabrication of waveguides on a variety of substrates including those with low melting points. The losses in these waveguides are typically less then 1 dB/cm, making them applicable to a variety of optical interconnect problems. In particular, we demonstrate their use in the fabrication of an optical power tap.
Research Interests:
Abstract-Highly efficient, reliable packaging of semiconductor op-tical devices such as lasers and optical amplifiers remains an expensive and challenging task. In this paper, we present an approach to single-mode fiber coupling which... more
Abstract-Highly efficient, reliable packaging of semiconductor op-tical devices such as lasers and optical amplifiers remains an expensive and challenging task. In this paper, we present an approach to single-mode fiber coupling which results in relaxed alignment tolerances ...
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Abstract-Highly efficient, reliable packaging of semiconductor op-tical devices such as lasers and optical amplifiers remains an expensive and challenging task. In this paper, we present an approach to single-mode fiber coupling which... more
Abstract-Highly efficient, reliable packaging of semiconductor op-tical devices such as lasers and optical amplifiers remains an expensive and challenging task. In this paper, we present an approach to single-mode fiber coupling which results in relaxed alignment tolerances ...
Research Interests:
The device requirements and system design issues for board-level optical links differ from their counterparts in optical links used for longer distance communications. We have fabricated a research prototype of a board-level optical link... more
The device requirements and system design issues for board-level optical links differ from their counterparts in optical links used for longer distance communications. We have fabricated a research prototype of a board-level optical link which is designed to operate in a high-speed digital equipment internal interconnect environment. The experimental transmitter and receiver packages are specifically designed for subminiaturized applications. We have explored the use of photolithographically patterned waveguides made of polymers as an alternative to the use of fiber at the board level. The major aspects of the device design are reviewed, but the emphasis of this paper is the systems-level design issues. We will discuss the design goals and the performance of the link. The results of this work demonstrate the feasibility of optics for signal distribution at the board level.
Research Interests:
Research Interests:
Research Interests:
A focused argon-ion laser beam (λ=350 nm) is used to fabricate optical channel waveguides on oxidized silicon wafers using a commerically available spin-on polymer. The polymerization process is photon induced, thus allowing the reaction... more
A focused argon-ion laser beam (λ=350 nm) is used to fabricate optical channel waveguides on oxidized silicon wafers using a commerically available spin-on polymer. The polymerization process is photon induced, thus allowing the reaction to occur in a room-temperature ambient. This allows the fabrication of waveguides on a variety of substrates including those with low melting points. The losses in these waveguides are typically less then 1 dB/cm, making them applicable to a variety of optical interconnect problems. In particular, we demonstrate their use in the fabrication of an optical power tap.