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ABSTRACT: Secure networks composed of optical networks and quantum key distribution (QKD) are considered in this paper. A network layer structure is defined to focus on issues important with respect to the QKD network layer that controls QKD links and supplies a secure key for message transmission. A multiple-user QKD network layer can be constructed with timing synchronization, secure key sharing between indirectly connected nodes with switched QKD systems and key relays, and key management to control the volume of key generation and supply in response to the demand from optical network nodes.
IEEE Journal of Selected Topics in Quantum Electronics 01/2010; · 3.78 Impact Factor
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ABSTRACT: We investigated the characteristics of shared keys obtained through quantum key distribution (QKD) from the viewpoint of application in cipher communication. We demonstrated that the shared keys at each stage in QKD satisfy the criteria determined by a standardized randomness test by physically compensating for randomness degrading factors. We also examined the increase in the error rate of the shared keys produced by privacy amplification, and succeeded in suppressing the error rate increase by applying a new privacy amplification scheme, which yielded a sufficiently low error rate for the final keys. These investigations showed that the final keys obtained using quantum cryptosystems are available as crypto keys in cipher communication.
IEEE Journal of Selected Topics in Quantum Electronics 01/2010; · 3.78 Impact Factor
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ABSTRACT: A novel interferometric technique is proposed for high-capacity quantum key distribution using wavelength division multiplexing. With additional phase modulation, we exhibited valid interference at any wavelengths while sharing interferometers over multi-channels, resulting in a low-cost configuration.
Optical Communication, 2009. ECOC '09. 35th European Conference on; 10/2009
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A. Tanaka,
M. Fujiwara,
Sae Woo Nam,
Y. Nambu,
S. Takahashi,
W. Maeda,
K.-I. Yoshino,
S. Miki,
Burm Baek,
Zhen Wang, A. Tajima,
M. Sasaki,
A. Tomita
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ABSTRACT: Recent progress in quantum key distribution (QKD), regarding high-speed and long-distance experiments and field trials are briefly reviewed. We also introduce our research on the randomness of quantum key. We have confirmed a quantum key, as a crypto key, assures the required randomness with some dynamic compensation.
Optical Communication, 2008. ECOC 2008. 34th European Conference on; 10/2008
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ABSTRACT: We propose a simple key-management technique using novel crypto-key supply. We have also successfully demonstrated a five-node QKD network that uses dynamic quantum key generation and on-demand crypto-key supply.
Optical Communication, 2008. ECOC 2008. 34th European Conference on; 10/2008
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ABSTRACT: We propose and demonstrate a new method of coding for quantum key distribution using a commercial dual-drive Mach-Zehnder modulator. This method allows the user to switch between two coding modes merely by changing the driving sequence of the modulator. We obtained error rates (0.7%) sufficiently low for practical use.
Optical Communication (ECOC), 2007 33rd European Conference and Ehxibition of; 10/2007
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ABSTRACT: To make a central pattern generator (CPG) for articulated robots, we discuss Van del Pol (VDP) oscillator. It is difficult to analyze the output of VDP oscillator. The parameter design of VDP oscillator is considered with two cases which are single oscillator and two oscillators coupled with respect to one another, according to some numerical simulations
SICE-ICASE, 2006. International Joint Conference; 11/2006
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ABSTRACT: A novel modulation scheme for making a high-speed Quantum-key-distribution (QKD) with decoy-state is proposed and confirmed. Using the proposed scheme, photon number is optimised, and high-speed QKD with decoy-state for a metro-area network has successfully established.
Optical Communications, 2006. ECOC 2006. European Conference on; 10/2006
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ABSTRACT: Recent progress in quantum key distribution (QKD) network technologies including an optically switched multi-user QKD network and activities for QKD performance improvements are presented.
Optical Communications, 2006. ECOC 2006. European Conference on; 10/2006
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ABSTRACT: Frame synchronization and supervisory control scheme were proposed for use in QKD, which all were based on QBER monitoring. Using these techniques proposed here, two weeks of continuous quantum key generation were performed through a field aerial fiber.
Lasers and Electro-Optics Society, 2005. LEOS 2005. The 18th Annual Meeting of the IEEE; 11/2005
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ABSTRACT: We propose a skew-insensitive frame-by-frame synchronization scheme for Tb/s optoelectronic packet-switch fabrics (PSFs). The proposed scheme employs an instantaneous-frame-reception technique and an automatic-frame-alignment technique. Cable length and transmission delay adjustment in erbium-doped fiber amplifiers and interconnects across shelves and cabinets are no longer necessary. The proposed scheme minimizes the frame header overhead such as a guard-time pattern and maximizes the effective bandwidth of the PSF. A partially installed 2.56-Tb/s PSF testbed, in spite of the presence of cables whose length is not known, demonstrates error-free switching of frames with a guard-time length as short as 3 ns.
IEEE Photonics Technology Letters 01/2000; · 2.19 Impact Factor
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M. Fukaishi,
S. Nakamura, A. Tajima,
Y. Kinoshita,
Y. Suemura,
H. Suzuki,
T. Itani,
H. Miyamoto,
N. Henmi,
T. Yamazaki,
M. Yotsuyanagi
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ABSTRACT: A 2.125-Gb/s transmitter meeting the specifications of the
emerging ANSI Fiber Channel standard has been developed using BiCMOS
technology. This transmitter features (1) a fully bipolar 10:1
multiplexer (MUX) and a 2.125-GHz retimer for high-accuracy transmission
of data, (2) an emitter-coupled logic (ECL) CMOS analog phase-locked
loop, (3) pure ECL-level output for direct connection to the currently
available optical modules, and (4) BiCMOS process technology that
includes 0.25-μm CMOS devices and 20-GHz bipolar devices. The LSI
serializes 32-bit-wide, 53.125-Mb/s data into 2.125-Gb/s data through a
CMOS 8B10B encoder. The chip area is 3×2 mm<sup>2</sup>, and the
power dissipation is 860 mW
IEEE Journal of Solid-State Circuits 10/1999; · 3.23 Impact Factor
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ABSTRACT: A 10-Gbit/s optical asynchronous cell-packet receiver with a fast
bit-synchronization circuit has been developed for achieving beyond
Tbit/s optical switch. Less than nine-bit fast acquisition time and
<1.5 dB receiver sensitivity penalty have been achieved
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: A packet/cell-based optical switch-fabric demonstrator has been
successfully developed that is upgradable to 2.56 Tb/s throughput. The
number of optical components in a 256×256 switch-fabric is
dramatically reduced to one-eighth that of a conventional switch-fabric
Optical Communication, 1998. 24th European Conference on; 10/1998
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ABSTRACT: We propose an implementation of a terabits-per-second crossbar-equivalent switch-fabric for packet-switching networks. It consists of switch-modules employing semiconductor optical amplifier gates (SOAGs), arrayed waveguide grating routers, and multiple wavelength-channels. It offers large modularity and a small internal loss. The number of SOAGs in a 256/spl times/256 switch-fabric is one-eighth that of a conventional switch-fabric. Scalability up to 2.56 Tb/s is demonstrated by a 10 Gb/s transmission experiment in which the input level into the switch-module was observed to possess a dynamic range of 6 dB.
IEEE Photonics Technology Letters 09/1998; · 2.19 Impact Factor
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ABSTRACT: A novel space-division optical switch configuration is proposed that incorporates a low-loss single-mode-to-multimode (SM-to-MM) combiner. We have confirmed the feasibility of a 16/spl times/16 10-Gb/s/port optical crossbar switch through an experiment with a silica waveguide combiner.
IEEE Photonics Technology Letters 02/1998; · 2.19 Impact Factor
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Y. Kinoshita,
H. Suzuki,
S. Nakamura,
M. Fukaishi, A. Tajima,
Y. Sucmura,
T. Itani,
H. Miyamoto,
H. Fujii,
M. Yotsuyanagi,
N. Henmi,
T. Yamazaki
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ABSTRACT: This paper presents an advanced BiCMOS process integration
technology, which employs 0.25-μm Ti salicide p<sup>+</sup>/n<sup>+
</sup> dual gate CMOSFETs, double poly-Si self-aligned bipolar
transistors and passive elements such as double poly-Si capacitors and
poly-Si resistors, while reducing the number of process steps. We also
have demonstrated a one-chip transceiver LSI circuit for an optical data
link using the ANSI fiber-channel standard of 4.25 Gb/s. The voltage
controlled oscillator (VCO) of the clock recovery circuit oscillates
from 3.2 GHz to 6.8 GHz according to the control voltage
Bipolar/BiCMOS Circuits and Technology Meeting, 1997. Proceedings of the; 10/1997
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ABSTRACT: A synchronous optical network interconnecting processor effectively reduces network latency and enhances bandwidth. If however, synchronization is not accurate and stable, skew and jitter in received packets may cause transmission errors. Timing margin design must consider the tolerance of the receiver to the skew and jitter. A theoretical analysis shows that the tolerance is ±12% of a bit period. Synchronization by clock distribution is achieved on an 8.5 Gbit/s/port packet-switch testbed utilizing semiconductor optical amplifier gates. An experiment shows that the sensitivity penalty induced by removing the preamble from the packet header and suppressing guard time is less than 0.5 dB.
Massively Parallel Processing Using Optical Interconnections, 1997., Proceedings of the Fourth International Conference on; 07/1997
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S. Nakamura, A. Tajima,
Y. Kinoshita,
Y. Suemura,
M. Fukaishi,
H. Suzuki,
T. Itani,
H. Miyamoto,
N. Henmi,
T. Yamazaki,
M. Yotsuyanagi
[show abstract]
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ABSTRACT: Demand for high-speed serial data communication systems is
increasing for computer data links using the 4.25Gb/s ANSI fiber-channel
standard. A clock-recovery circuit (CRC) that extracts a clock signal
from the transmitted data stream is essential for these systems. An
AV-DSPD architecture operates at a frequency two times higher than that
of an internal phase detector that limits the conventional CRC
frequency. A CRC VCO is controlled by the absolute value of divided
signal phase differences (AV-DSPD). Based on the AV-DSPD architecture, a
4.25GHz CRC is suitable for non return to zero (NRZ) data streams.
Although the CRC consists of bipolar transistors, fabrication is in
0.251μm BiCMOS allowing the CRC to be integrated with other digital
blocks, such as a byte-lock detector, necessary for data link systems
using the fiber-channel standard
Solid-State Circuits Conference, 1997. Digest of Technical Papers. 43rd ISSCC., 1997 IEEE International; 03/1997
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ABSTRACT: This paper describes an adaptive wavelength tunable optical
filter, which is composed of an angle-tuned interference optical filter
and an intelligent digital controller. The new angle-tuned interference
filter consists of a dielectric interference optical filter and a
piezoelectric angle-tuning mechanism. It achieves quick wavelength
switching within 2.5 ms in a 30 nm tuning range and a sufficiently low
crosstalk less than -30 dB. The intelligent digital controller has two
functions: wavelength tracking and wavelength channel selection.
Combining these technologies, we have developed a practical low-cost
tunable filter suitable for a post-optical-amplifier filter in a
high-sensitivity detection system and a channel selector in a WDM system
that requires 10-100 ms channel selection time. With a wavelength
tracking operation, we have confirmed -35 dBm high-sensitivity detection
in 20 nm wavelength range in a 10 Gb/s system. We have also confirmed a
wavelength channel selection operation within 18 ms in a three-channel
wavelength division multiplexed (WDM) system whose channel spacing is
4.4 nm
Journal of Lightwave Technology 07/1996; · 2.78 Impact Factor
