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ABSTRACT: We have demonstrated powerful new techniques for identifying the optical impairments causing the degradation of an optical channel. We use machine learning and pattern classification techniques on eye diagrams to identify the optical impairments. These capabilities can enable the development of low-cost optical performance monitors having significant diagnostic capabilities
IEEE Photonics Technology Letters 12/2006; · 2.19 Impact Factor
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ABSTRACT: The characterization of the transfer function of the power line (PL) channel is a nontrivial task that requires a truly interdisciplinary approach. Until recently, a common attribute and limitation of existing models for the PL channel transfer function lay in the phenomenological or statistical approach usually followed. This approach allows one to describe the channel only partially, e.g., as dominated by multipath-like effects, and prevents one from unveiling special properties of it. Multiconductor transmission line (MTL) theory was recently found by the authors to be a useful and accurate tool in modeling the PL transfer function while, at the same time, taking into account the wiring and grounding practices mandated by several regulatory bodies for commercial and residential premises. Crossing several layers of abstraction and following a bottom-up approach, complex circuit-level models originating from MTL theory can be manipulated and represented in terms of cascaded two-port networks (2PNs), thus allowing one to compute a priori and in a deterministic fashion the transfer function of any PL link. In the present contribution, we present additional analysis and data that validate the accuracy of the MTL approach and further justify its use in the PL channel context. Moreover, we also describe in detail the methodology to follow for modeling both grounded and ungrounded PL links in a unified framework. A consequence of the validity of the proposed modeling is that it can facilitate the process of standardization of the PL transfer function, an important step toward the availability of a commonly agreed upon (set of) channel transfer functions.
IEEE Journal on Selected Areas in Communications 08/2006; · 3.41 Impact Factor
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ABSTRACT: Considerable effort has recently been devoted to the determination of accurate channel models for the power line (PL) environment, for both the indoor and outdoor cases. The common denominator (and limitation) of the known and previously published models is the particular type of approach followed. In fact, until now, the PL channel (PLC) has been treated from a mere phenomenological or statistical point of view. This allows us to describe the channel only partially, e.g., as dominated by multipath-like effects, and prevents us from unveiling any of its particular properties. We report results about a new approach to the modeling of the PLC based on multiconductor transmission line (MTL) theory. The need for an MTL approach arises from the fact that indoor power cables consist of three conductors, and not just two as for classical twisted-pair and coaxial cable cases. This approach allows us to include wiring and grounding practices dictated by the United States National Electric Code (NEC). On the basis of this modeling, we reveal that the PLC is a more deterministic medium than commonly believed. Moreover, it is also possible to prove an interesting symmetry property of the PLC that was previously unknown: the PLC, regardless of its topology, exhibits the same transfer function when driven from either side, provided that the source and load impedances are the same.
Consumer Communications and Networking Conference, 2004. CCNC 2004. First IEEE; 02/2004
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P. Toliver,
R.J. Runser,
T.E. Chapuran,
J.L. Jackel, T.C. Banwell,
M.S. Goodman,
R.J. Hughes,
C.G. Peterson,
D. Derkacs,
J.E. Nordholt,
L. Mercer,
S. McNown,
A. Goldman,
J. Blake
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ABSTRACT: Quantum key distribution (QKD) enables unconditional physical layer security for the distribution of cryptographic key material. However, most experimental demonstrations have relied on simple point-to-point optical links. In this paper we investigate the compatibility of QKD with reconfigurable optical networks. By performing the first tests of QKD transmission through optical switches, we study if there are impairment mechanisms other than switch insertion loss that impact the sifted and error corrected secret bit yield. Three types of transparent optical switch elements are investigated including lithium niobate (LiNbO/sub 3/), microelectromechanical systems (MEMS), and optomechanical. We show that QKD can be extended beyond point-to-point links to switched multinode architectures including protected ring networks to enhance quantum channel availability.
IEEE Photonics Technology Letters 12/2003; · 2.19 Impact Factor
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ABSTRACT: The "indoor" access network is characterized by several branches and impedance mismatches that cause many reflections. In the present paper, a new way of modeling the transfer function of a power line is proposed. The proposed model starts by considering the power line channel as a uniform transmission line. This allows the power line channel to be described as a cascade of simple two-port networks, each of which may be easily described with its transmission matrix. This approach allows us to model in the frequency domain any power line channel, regardless of its topology, by considering as special two-port networks any series or shunt impedances (i.e., branches) present along the line. This approach also implies the validity of the TEM approximation. It is possible to prove that this assumption is valid assuming correct mode excitation, which differs from conventional twisted pair. In so doing, the usual problems encountered in the time-domain characterization of the power line channel as a multipath channel can be avoided. Interestingly, the transmission matrices approach allows us also to show the existence of a particular symmetry of the power line channel that was not previously revealed [5].
08/2001;
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ABSTRACT: The "indoor" power line network is characterized by several branches and impendence mismatches that cause many reflections. In the present paper, we address the problem of determining the exact conditions under which the power line channel may be considered a symmetric channel, i.e. exhibiting the same frequency transfer function from either side. By using a new way of modeling the power line channel by means of transmission matrices [3], it is here shown for the first time that the power line channel is, indeed, a symmetric channel. Moreover, it is also shown that this property holds regardless of the topology of the link and that the only condition for symmetry is the requirement that the source and load impedances used to terminate the line be the same. The proposed approach implies the validity of the TEM approximation. It is possible to prove that this assumption is valid assuming correct mode excitation, which differs from conventional twisted pair. Interestingly, the transmission matrices approach allows us also to characterize easily in the frequency domain the effects of the multi-path nature of the power line channel [3].
08/2001;
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ABSTRACT: We demonstrate error free transmission of multirate optical bursts over a metropolitan WDM network with EDFA designed for constant average power by using an all-optical means for optical signal stabilization.
Optical Communication, 2001. ECOC '01. 27th European Conference on; 02/2001
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ABSTRACT: A simple analytical expression is presented for the current flow
in a diode driven by a voltage source through a series resistance. The
proposed solution is based on the Lambert W-function. The new expression
leads to an efficient method for extracting series resistance from
measured current-voltage data. Experimental results are presented which
validate the proposed solution and extraction method
Electronics Letters 03/2000; · 0.96 Impact Factor
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ABSTRACT: We report a programmable, rapid-response bit-rate detection and selection circuit that can handle a discrete and continuous range of data rates from 10 Mb/s to 1.3 Gb/s for programming burst mode and conventional clock data regeneration (CDR) functions
Optical Fiber Communication Conference, 1999, and the International Conference on Integrated Optics and Optical Fiber Communication. OFC/IOOC '99. Technical Digest; 02/1999
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ABSTRACT: Experimental research prototype packages with 26 10 Gb/s I/O ports were designed for two GaAs telecom ICs. The prototypes are based upon a commercially available ceramic microwave package with an exterior size of 0.450" square, and an interior cavity size of 0.250" square. The copper-tungsten base provides excellent heat dissipation and rigidity while providing a close thermal expansion match to GaAs. A 5 mil alumina substrate is used to carry microstrip transmission line circuits from the package edge to the die mounted at the package center. A low-inductance ground ring surrounds the die cavity in the package to provide flexible low-noise grounding of the die without compromising signal integrity on the high-speed lines. Measurements show the package has usable bandwidth to 35 GHz and crosstalk is better than -35 dB for adjacent high-speed signal paths. The results demonstrate that packaging need not be the limiting factor for complex high-speed digital integrated circuits
Microwave Symposium Digest, 1997., IEEE MTT-S International; 07/1997
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ABSTRACT: SONET OC-192 with a data transmission rate of 9.95328 Gb/s has emerged as the next generation high capacity optical carrier. This paper presents the first complete implementation of 10 Gb/s multiplexing, demultiplexing and SONET framing functions on a 3-chip chip-set. The chip-set consists of an 8:1 multiplexer with auto phase alignment, a 1:8 demultiplexer with SONET frame detection and a multi-purpose interface chip to simplify system integration-all designed to operate at 10 Gb/s for use in an experimental SOMET OC-192 self-healing ring test bed. These experimental research prototype devices are based on the AlGaAs/GaAs Hetero-junction Bipolar Transistor (HBT) technology (f<sub>t </sub>=60 GHz). High speed packaging and system integration issues are also addressed
Gallium Arsenide Integrated Circuit (GaAs IC) Symposium, 1996. Technical Digest 1996., 18th Annual; 12/1996
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ABSTRACT: EMI/EMC is a dominant problem encountered in high bit-rate
(>100 Mb/s) transmission over unshielded twisted-pair cable (UTP)
which leads to a novel set of line-code dependent tradeoffs affecting
transceiver and cable plant complexity. To understand the tradeoffs, the
authors examined the factors affecting RF emissions and susceptibility
in both trellis-configured cable plant models and installed cable plant.
An analytical model is presented that describes mode conversion by
discontinuities in multi-pair UTP cable plant. Termination of the three
dominant propagating modes produces consistently lower radiated
emissions than other standard cable termination procedures. Cable plant
parameters which predict good transmission do not assure satisfactory
EMI performance. Radiated emissions from the trellis model occur in
broad bands at 43, 53, 60, 70, and 80 MHz, and show a positive
correlation with the transmit signal spectrum. For a given transmit
level at 155 Mb/s, the emissions with MLT3 and BPR1 were 8-13 dB (10 dB
typ) and 4-20 dB (13 dB typ) below NRZ levels, respectively. The authors
also compared the performance of NRZ, MLT3, BPR1, and BPR4 line codes in
an experimental 155 Mb/s link with 100 m of UTP5 by measuring the BER
sensitivity to both injected noise and pseudo-random data sequence
length. When the measured receiver penalty associated with three levels
is included, MLT3, BPR1, and BPR4 offer 5-15 dB better performance over
NRZ at 155 Mb/s, although implementation complexity is greater
IEEE Journal on Selected Areas in Communications 01/1996; · 3.41 Impact Factor
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ABSTRACT: EMI/EMC is a dominant problem encountered in high bit-rate transmission over unshielded twisted pair cable (UTP). This leads to a novel set of design tradeoffs between transceiver complexity (near term cost) and cable plant complexity (long term cost) for 155 Mb/s transmission on twisted pair cable which depends on the choice of line code. To understand the tradeoffs, the factors affecting RF emissions and susceptibility were examined in both installed cable plant and trellis configured cable plant models, which included both category 5 cable and interconnection hardware. In addition, the BER sensitivity to injected noise and pseudo-random data sequence length was measured for experimental 155 Mb/s links with 100 meters of category 5 cable using NRZ, MLT3, BPR1 and BPR4 line codes. A model for common-mode conversion in multi-pair UTP cables is presented. Radiated emissions occur in broad bands at 43, 53, 60, 70, and 80 MHz and show a positive correlation with the transmit signal spectrum. Termination of all propagating modes produced consistently lower radiated emissions than other standard cable termination procedures. For a given transmit level at 155 Mb/s, MLT3 has the lowest emissions between 30-50 MHz while BPR1 has the lowest emissions above 60 MHz. The emissions with MLT3 and BPR1 were 8-13 dB (10 dB typical) and 4-20 dB (13 dB typical) below NRZ levels, respectively. When the measured receiver penalty associated with three levels is included, MLT3, BPR1 and BPR4 still offer 5-15 dB better performance over NRZ at 155 Mb/s, although implementation complexity is greater as well
Computers and Communications, 1995. Conference Proceedings of the 1995 IEEE Fourteenth Annual International Phoenix Conference on; 04/1995
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T.C. Banwell
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ABSTRACT: The performance of low-voltage bandgap regulators built with only
npn transistors is examined. The power supply rejection ratio (PSRR) is
significantly constrained, more than any other performance parameter, by
the exclusion of a complimentary active load. The PSRR for an inherently
stable (single operating point) bandgap regulator built using only npn
transistors is bounded below by 2.5
(nV<sub>T</sub>/V<sub>cc</sub>)<sup>n</sup>=0.7 mV/V or 0.04 mV/V for
circuits with n=2 or 3 stages, respectively. This represents a
“gain” constraint imposed by the coincidence of signal and
bias paths in bipolar circuits which employ current differencing or
bootstrapping techniques. Base current errors can significantly degrade
PSRR. Two all-npn circuits are presented with PSRR ⩽0.1 mV/V that
exhibit a single operating point under most circumstances
IEEE Transactions on Circuits and Systems II Analog and Digital Signal Processing 04/1995;
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T.C. Banwell
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ABSTRACT: Describes a new bias current regulation circuit for single-stage
bipolar and FET amplifiers which achieves high precision and simplicity
through a combination of feedback error amplifier with bandgap
reference. The internally generated reference voltage can be preset
between 100-200 mV. The approach is ideal for applications where the
overhead voltage must be minimized to reduce power dissipation, and
typically offers <0.5% regulation and ⩽40 ppm/°C temperature
coefficient. The authors present three common applications which
demonstrate the unique advantages of the new topology
IEEE Journal of Solid-State Circuits 03/1994; · 3.23 Impact Factor
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ABSTRACT: Recent successes in transporting optical power near the 1-W level via optical fiber suggest that it may be possible to operate conventional telephone station sets using electricity derived photovoltaically from light in a fiber. The authors investigate the constraints on optical powering in fiber-in-the-loop (FITL) applications and assess its applicability in terms of end-to-end efficiency, loop length, and system cost. To make this assessment, they look at several different optical-powering system architectures and components vis-a-vis their cost-versus-delivered-power capability. Related issues such as safety and reliability are discussed.
Journal of Lightwave Technology 04/1993; · 2.78 Impact Factor
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T.C. Banwell
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ABSTRACT: There is a growing need to reduce the power consumption of the
high-speed components in broadband telecommunications networks. This
will require that power processing be treated simultaneously with signal
processing in the development of new broadband products. The power
consumption of fiber optic transmitters, which can use either lasers or
LEDs, is considered to be relatively large. LED transmitters normally
require considerably more operating power than lasers, which is often
the deciding factor in the selection of a laser rather than an LED in
short span 100-200 Mb/s fiber optic links. The LED transmitter issue
therefore represents a good opportunity for examining new strategies to
improve power-hungry technologies. The overall performance of an LED
transmitter can be enhanced by using the available supply voltage more
efficiently through power conditioning. A prototype 155 Mb/s LED
transmitter that achieves a threefold improvement in power efficiency is
described
IEEE Transactions on Power Electronics 02/1993; · 4.65 Impact Factor
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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
<sup>-13</sup> 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
Global Telecommunications Conference, 1992. Conference Record., GLOBECOM '92. Communication for Global Users., IEEE; 01/1993
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ABSTRACT: An electroplating technique for permanently fixing single-mode
fibers into position in optical device packages is described. In this
technique, the fiber is mounted in a metal tube and aligned to an
optical device mounted on a metal substrate. The fiber is in close
proximity to the substrate and a flexible conductive gel is used to
connect the two electrically. The fiber, gel, and substrate thus form
the plating cathode. When immersed in a plating bath with an anode
inserted, metal can be deposited across the gel, forming a strong metal
bridge between the fiber and substrate, locking the fiber into position.
Under appropriate conditions, misalignments within ±1 μm
during the plating process have been observed. This technique was used
to package a laser diode transmitter, which locked the laser-to-fiber
alignment to within 0.7 μm, or 0.1 dB of the optimum coupled power
Journal of Lightwave Technology 08/1992; · 2.78 Impact Factor
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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<sup>-13</sup>. The transmission performance of the single-pair unshielded cable is compared with that of four-pair unshielded twisted pair cables.
Electronics Letters 07/1992; · 0.96 Impact Factor
