A5036262026- Optical Network Technologies
- Photonic and Optical Devices
- Advanced Photonic Communication Systems
- Advanced Fiber Laser Technologies
- Semiconductor Lasers and Optical Devices
- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
- Particle physics theoretical and experimental studies
- Advanced Optical Network Technologies
- High-Energy Particle Collisions Research
- Laser-Matter Interactions and Applications
- Optical Coatings and Gratings
- Neural Networks and Reservoir Computing
- Quantum Chromodynamics and Particle Interactions
- Solar and Space Plasma Dynamics
- Neutrino Physics Research
- PAPR reduction in OFDM
- Advanced Fiber Optic Sensors
- Advanced Optical Imaging Technologies
- Gamma-ray bursts and supernovae
- Optical Coherence Tomography Applications
- Catalytic Processes in Materials Science
- Catalysis and Oxidation Reactions
- graph theory and CDMA systems
- Spectroscopy Techniques in Biomedical and Chemical Research
Waseda University
2024
Osaka University
2014-2023
Kindai University
1986-2011
Nara University
2011
Laboratoire Charles Fabry
2009
Graduate School USA
2007
Hiroshima University
2000-2001
Japan Chemical Industry Association
2001
The University of Tokyo
1996-1999
Kobe University
1997-1998
This paper reports the first discovery of TeV gamma-ray emission from a supernova remnant made with CANGAROO 3.8 m Telescope. gamma rays were detected at sky position and extension coincident north-east (NE) rim shell-type Supernova (SNR) SN1006 (Type Ia). has been most likely candidate for an extended Gamma-ray source, since clear synchrotron X-ray rims was recently observed by ASCA (Koyama et al. 1995), which is strong evidence existence very high energy electrons up to hundreds in SNR....
We propose a new, to our knowledge, method for an all-optical analog-to-digital converter by using self-frequency shifting in fiber and pulse-shaping technique. Preliminary experimental results show that various digitized temporal bit signals can be generated the variation of power ultrashort analog input pulse less than 1 ps.
Gamma rays with energies greater than 7 TeV from the Crab pulsar/nebula have been observed at large zenith angles, using Imaging Atmospheric Technique Woomera, South Australia. CANGAROO data taken in 1992, 1993 and 1995 indicate that energy spectrum extends up to least 50 TeV, without a change of index power law spectrum. The differential is \noindent $(2.01\pm 0.36)\times 10^{-13}(E/{7 TeV})^{-2.53 \pm 0.18} TeV^{-1}cm^{-2}s^{-1}$ between TeV. There no apparent cut-off. for photon above...
We demonstrate and investigate resolution improvement of optical quantization using soliton self-frequency shift (SSFS) coding interconnection for an all-optical analog-to-digital conversion (ADC). Incorporating spectral compression into the allows us to improve bit according ratio with keeping its throughput. The proposed scheme consists SSFS self-phase modulation (SPM) induced based on a binary table. In quantization, powers input signals are discriminated by referring center wavelengths...
We have studied inclusive ${K}_{S}^{0}$, $\ensuremath{\Lambda}$, and $\overline{\ensuremath{\Lambda}}$ production strange-resonance in the reactions $\mathrm{pp}\ensuremath{\rightarrow}({K}_{S}^{0}, \ensuremath{\Lambda}, or \overline{\ensuremath{\Lambda}})+{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}+\mathrm{anything}$ at 405 GeV/c. The observed cross sections are 7.43 \ifmmode\pm\else\textpm\fi{} 0.45 mb for 4.01 0.35 0.63 0.12 $\overline{\ensuremath{\Lambda}}$. From analyses of...
We demonstrate a resolution upgrade toward 6 bit optical quantization using power-to-wavelength conversion without an increment of system parallelism. Expansion full-scale input range is employed in conjunction with reduction step size keeping sampling-rate transparency characteristic over several 100 sGS/s. The effective number bits estimated to 5.74 bit, and the integral nonlinearity error differential are less than 1 least significant bit.
In this letter, we report the experimental demonstration of a 40 GSample/s all-optical analog to digital converter (ADC). The proposed ADC consists optical quantization and coding processes based on intensity-to-wavelength conversion by soliton self-frequency shift with an sampling process using ultrastable pulse train. A 5-GHz sinusoidal input signal was successfully converted digitized output in real time no degradation resolution. (High rate operation may lead resolution due reduction...
We report the attempt of optical quantization and coding in 5-bit parallel format for photonic A/D conversion. The proposed system is designed to realize generation 32 different codes proportion corresponding signal levels when fed a certain range amplitude-varied input pulses setup. Optical bit-parallel made it possible, that provides 5 bit from quantized pulses. operation an module with multi-ports was tested our experimental
Polarization-multiplexed phase-only diffractive optical elements with subwavelength structures are proposed and fabricated. The differences among the phase modulations result from effective indices exhibited in various filling factors surface profiles, retardations obtained by relief depth of structures. polarization-selective property is achieved polarization dependence one-dimensional independence two-dimensional Additionally, contrast our polarization-multiplexed elements, defined as...
We propose and demonstrate an optical coding scheme using interconnection for a photonic analog-to-digital conversion. It allows us to convert multi-power level signal into multiple-bit binary code so as detect it in bit-parallel format by photodiode array. The proposed is executed after quantization self-frequency shift. Optical based on conversion table generates appropriate allocation of identification which provided result quantization. Experimental results show that 8-levels analog...
We propose and demonstrate a wavelength- time-selective reconfigurable optical add/drop multiplexer (ROADM) using time-frequency domain processing. The proposed ROADM is realized by allocating wavelength channels time slots to corresponding 2D spatial on MEMS switch. Experimental results show the drop operation for signal with equivalent 3.2 Tb/s (0.64 channels), reconfigurability switching of
We report the experimental demonstration of a 10-GS/s 5-bit real-time optical quantization using soliton self-frequency shift (SSFS) and multistage spectral compression. prove feature sampling rate transparency at 10 GS/s by transmitting 10-Gb/s multi-intensity level quasi analog signals through our quantizer. Furthermore, to confirm performance quantizer, we measure bit-error-rate calculate effective number bits, integral nonlinearity error, differential error.
We experimentally realize seamless operations with below 100-fs timing jitter in a 10-GSample/s 3-bit photonic analog-to-digital converter (ADC) an input 2.5-GHz sinusoidal electrical signal. To address the energy efficiency, it is necessary to explore some serial approaches get most ADC done before serial-to-parallel conversion save number of devices. press forward work on subsequent after optical sampling ADC, we have investigated quantization and coding demonstrated their performances....
Very High Energy Gamma Rays from the Vela Pulsar Direction, T. Yoshikoshi, Kifune, S. A. Dazeley, P. G. Edwards, Hara, Y. Hayami, F. Kakimoto, Konishi, Masaike, Matsubara, Matsuoka, Mizumoto, M. Mori, H. Muraishi, Muraki, Naito, K. Nishijima, Oda, Ogio, Ohsaki, J. R. Patterson, D. Roberts, Rowell, Sako, Sakurazawa, Susukita, Suzuki, Tamura, Tanimori, Thornton, Yanagita, Yoshida
We propose an optical time-to-two-dimensional (2-D)-space-to-time-to-2-D-space conversion technique for ultrafast image transmission with ultrashort-pulse lasers. The proposed is based on the concepts of time–space transform, spatial time–frequency and their inverses. describe analyze all-optical processors that can convert input 2-D object into a modulated pulse sequence retrieve original from temporal signals transmitted through fiber channel ultrahigh bandwidth. To verify technique, we...
We propose and demonstrate a novel all-optical digital-to-analog (D/A) conversion using pulse pattern recognition based on optical correlation processing. It is composed of processing intensity adjustment an attenuator. obtain single as result by between target digital signal prepared filter function. The obtained can be promptly fed to output port corresponding analog through adequate adjustment. Experimental results show that four-bit signals with 1.65ps interval successfully converted...
The Large Area Air Shower (LAAS) group has been performing a network observation of extensive air showers (EAS) since 1996 in Japan. Eight compact EAS arrays (ten the near future) are operating simultaneously and independently at distant stations (up to ≈ 1000 km), constituting gigantic detector system as whole. Using five stations' datasets, large-scale coincidences have searched for with aim detecting signals from extremely short bursts universe. By comparing arrival times directions all...
A conventional method to synthesize diffractive optical elements and computer-generated holograms (CGH's) with high diffraction efficiency relies on an increase of phase levels. To fabricate such a device, one should perform electron-beam (e-beam) lithography multiple-dose exposures or multiple-step photolithography. Here we describe one-step method, which is based the effective medium theory, for fabrication multilevel CGH. The modulations required in cells CGH are constructed by means...
We developed a novel fabrication method of reduced wavelength-dependent quarter-wave plate (QWP) based on form birefringence multilayered subwavelength structure. The structure was constructed by depositing high-refractive-index thin film subwavelength-structured substrate with low refractive index. surface the shallow enough to be formed mass replication technology. A grating ridges sputtering Zn2SnO4 (refractive index 2.03 at wavelength 633 nm). Moreover, since grooves were very deep and...
Power-efficient, flexible, Nyquist 4.88-ps sinc-pulses generation and OTDM multiplexing is demonstrated, using fractional Fourier transform subcarriers time-lens effect. users are generated multiplexed by a WSS, without rectangular spectral shaping.
An all-optical M-ary amplitude shift keying (ASK) signal demultiplexer is proposed and demonstrated. It allowed us to seamlessly demultiplex a high bit-rate optical ASK into on-off (OOK) signals without O/E conversion. composed of multilevel thresholding using self-frequency OOK generation interconnection. A level identification provided as result it fed an interconnection circuit which can generate corresponding signals. We demonstrate the quadrature demultiplexing at 100 Gsymbol/s its...