A5100764560- Optical Network Technologies
- Advanced Photonic Communication Systems
- Semiconductor Lasers and Optical Devices
- Advanced Optical Network Technologies
- Photonic and Optical Devices
- Advanced Fiber Laser Technologies
- Software-Defined Networks and 5G
- Network Traffic and Congestion Control
- Semiconductor Quantum Structures and Devices
- Power Line Communications and Noise
- Optical Wireless Communication Technologies
- Laser-Matter Interactions and Applications
- Vehicular Ad Hoc Networks (VANETs)
- PAPR reduction in OFDM
- Neural Networks and Reservoir Computing
- Telecommunications and Broadcasting Technologies
- Rare-earth and actinide compounds
- Power Systems and Technologies
- Advanced MIMO Systems Optimization
- Molecular Junctions and Nanostructures
- IPv6, Mobility, Handover, Networks, Security
- Distributed and Parallel Computing Systems
- Advanced Wireless Communication Techniques
- Magnetic Properties of Alloys
- Cloud Computing and Resource Management
KDDI Research (Japan)
2004-2023
Hitachi (Japan)
1991-2023
Kindai University
2016-2023
National Institute of Advanced Industrial Science and Technology
1999-2020
Toyota Motor Corporation (Switzerland)
2015
KDDI (Japan)
2002-2012
Mitsubishi Group (Japan)
2003
Tokyo University of Agriculture and Technology
2003
Nippon Steel (Japan)
2003
Midorigaoka Hospital
1997
We discuss coherent optical orthogonal frequency division multiplexing (CO-OFDM) as a suitable modulation technique for long-haul transmission systems. Several design and implementation aspects of CO-OFDM system are reviewed, but we especially focus on phase noise compensation. As conventional systems very sensitive to laser novel method compensate is introduced. With the help this compensation show continuously detectable OFDM at 25.8 Gb/s data rate (20 after coding) over 4160-km SSMF...
We discuss optical multi-band orthogonal frequency division multiplexing (OFDM) and show that by using multiple parallel OFDM bands, the required bandwidth of digital-to-analogue/ analogue-to-digital converters cyclic prefix can significantly be reduced. With help four bands polarization (PDM) we report continuously detectable transmission 10 times121.9-Gb/s (112.6-Gb/s without overhead) at 50-GHz channel spacing over 1,000-km standard single mode fiber (SSMF) any inline dispersion...
<a href="http://jon.osa.org/virtual_issue.cfm?vid=54">Focus Issue on Orthogonal-Frequency-Division Multiplexed Communications Systems and Networks</a> We discuss the realization performance of polarization-division-multiplexed orthogonal frequency division multiplexing (PDM-OFDM) for long-haul transmission systems. Polarization demultiplexing PDM signal at receiver is realized by employing a multiple-input multiple-output (MIMO) detector. Using recirculating loop experiment reported 52.5...
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In order to realize a future 100-Gb Ethernet (100 GbE) transport, 100-Gb/s transmission without 100-GHz-class electronics and optical time-division-multiplexing technique was demonstrated. By using differential quadrature phase-shift-keying (DQPSK) modulation format commercially available electronics, 2- 50-km transmissions of signal were successfully achieved over standard single mode fiber. The receiver sensitivity, chromatic dispersion, group delay tolerances DQPSK also evaluated. Through...
Monolithic integration of a 1.55-μm InGaAsP/InP distributed feedback (DFB) laser and an electroabsorption (EA) modulator was studied. The difference between the lasing photon energy bandgap waveguide designed to be 30-40 meV, taking into account linewidth-enhancement factor zero-bias absorption loss. integrated devices were grown by three-step vapor phase epitaxy (VPE). CW threshold current at 20°C DFB part with buried heterostructure 30-60 mA breakdown voltage strip-loaded stripe geometry...
The authors propose and demonstrate a simple technique for generating transform-limited optical short pulse with variable repetition rates by using sinusoidally driven InGaAsP electroabsorption modulator without any resonators. Using the compression effect due to nonlinear attenuation characteristics of modulator, can be generated just sinusoidal modulation. Theoretical calculations experimental results show that shape is very close sech/sup 2/ shape, width easily varied varying bias...
A 15GHz optical pulse train with time-bandwidth product of 0.32 for soliton transmission was generated by a sinusoidally driven InGaAsP electroabsorption modulator, the first time. By using compression effect caused nonlinear attenuation response to applied voltage, transform-limited width 14 ps and spectral 23GHz successfully just sinusoidal modulation, without any electrical resonators.
During the last two years, numerous researchers have dedicated their work in optical OFDM and, consequently, number of papers has grown exponentially. In this paper we evaluate suitability for long-haul 100GbE applications.
<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> In this paper, we discuss the realization of wavelength-division multiplexing (WDM) transmission at high spectral efficiency. For experiment, coherent polarization-division multiplexing--orthogonal frequency-division (PDM-OFDM) is used as a modulation format. PDM-OFDM uses training symbols for channel estimation. This makes OFDM easily scalable to higher level formats estimation realized with...
In this letter, we investigate 132.2-Gb/s polarization-division-multiplexed orthogonal frequency-division-multiplexing (PDM-OFDM) transmission at 25-GHz channel spacing. We show that the nonlinear tolerance is dependent on OFDM symbol length. By using 14.4-ns-long symbols, 7 times of PDM-OFDM 4-b/s/Hz spectral efficiency reported over 1300-km standard single-mode fiber.
Spectral efficient transmission of 8×65.1-Gbit/s PDM-OFDM is reported over 240 km. Using coherent detection and 32-QAM subcarrier modulation the channel spacing reduced to 8 GHz, allowing a net spectral efficiency 7.0 bit/s/Hz.
Self-assembly is the process by which individual components arrange themselves into an ordered structure changing shapes, components, and interactions. It has enabled us to construct extensive range of geometric forms on many length scales. Nevertheless, potential two-dimensional polygonal nanoplates self-assemble extended three-dimensional structures with compartments corridors remained unexplored. In this paper, we show coarse-grained Monte Carlo simulations demonstrating self-assembly...
Single-carrier, single-polarisation 20 Gbit/s soliton data transmission over 11500 km with BER below 10-9 has been experimentally demonstrated using alternating-amplitude solitons and optical time-division multiplexing. This is the first report showing feasibility of 230 Tbit/skm capacity by single channel conventional amplifier systems.
Input optical power dependence of the modulation voltage for GaInAsP electroabsorption modulators is studied. It shown that photogenerated hole pile-up at a heterointerface induces increase same extinction ratio with increasing input power. The effect was greatly reduced in new structure buffer layer intermediate bandgap between waveguide and InP upper clad layers.
Electrical and optical interactions occurring in InGaAsP/InP integrated light sources composed of DFB lasers electroabsorption modulators have been studied. Static measurements indicated that an isolation resistance between the laser modulator should be as large 100 k Omega or more order to reduce a lasing wavelength shift associated with biasing modulator. The useful guided out was about 1-2 percent output. At high frequency modulation, asymmetric sidebands were observed dynamic spectra...
We propose a low-overhead method of polarization-multiplexed direct detection optical orthogonal frequency-division-multiplexing transmission that requires no digital multiple-input and multiple-output processing at the receiver. Optical filtering carrier components allows simple polarization separation. Using 16-quadrature amplitude modulation only 31-GHz bandwidth, 100-Gb/s over 80 km standard single-mode fiber is successfully demonstrated. The crosstalk penalty was 1.2 dB. also...
The total performance of an InGaAsP electroabsorption modulator was characterized. Low-driving voltage 1.2-2.7 V, low fiber-to-fiber insertion loss 8.4-7.8 dB, and small alpha -value 0.1-0.4 were obtained in 40-nm-wide wavelength range from 1.53 to 1.57 mu m. Static dynamic modulation characteristics showed dependence on the polarization power level input light. Successful applications a packaged EA ultralong-distance Er-doped fiber amplifier systems confirmed by 16000-4550-km transmission...
High-speed, low-chirp, and low voltage driving characteristics of 1.55- mu m lambda /4-shifted distributed-feedback (DFB) laser/InGaAsP electroabsorption modulator integrated light sources are reported. By optimization the composition thickness waveguide, for a 10-dB extinction ratio was reduced to 1.4-3 V, depending on length in range 240-125 m. High-speed modulation up 10-Gb/s NRZ achieved by device with 125- length. The linewidth enhancement factor estimated be 0.15-0.48.< <ETX...