A5038803848- Pulsars and Gravitational Waves Research
- Photonic and Optical Devices
- Semiconductor Lasers and Optical Devices
- Advanced Frequency and Time Standards
- Radio Astronomy Observations and Technology
- Optical Network Technologies
- Geophysics and Sensor Technology
- Cold Atom Physics and Bose-Einstein Condensates
- Geophysics and Gravity Measurements
- Advanced optical system design
- Nanofabrication and Lithography Techniques
- 3D IC and TSV technologies
- Advanced Optical Network Technologies
- Cosmology and Gravitation Theories
- Adaptive optics and wavefront sensing
- Advanced Photonic Communication Systems
- Gamma-ray bursts and supernovae
- Geotechnical and Geomechanical Engineering
- Electronic Packaging and Soldering Technologies
- Optical Coatings and Gratings
- Advancements in Photolithography Techniques
- Superconducting Materials and Applications
- Quantum Information and Cryptography
- Advancements in PLL and VCO Technologies
- Metallurgical and Alloy Processes
IBM Research - Tokyo
2010-2024
IBM (United States)
2010-2015
The University of Tokyo
2005-2008
Bunkyo University
2008
Tokyo University of Science
2006
Institute for Cosmic Ray Research
2004
Kavli Institute for the Physics and Mathematics of the Universe
2004
DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space gravitational antenna. It aims at detecting various kinds of waves between 1 mHz and 100 Hz frequently enough to open a new window observation for astronomy. The pre-conceptual design DECIGO consists three drag-free satellites, 1000 km apart from each other, whose relative displacements are measured by Fabry–Perot Michelson interferometer. We plan launch in 2024 after long intense development...
We present data-analysis schemes and results of observations with the TAMA300 gravitational wave detector, targeting burst signals from stellar-core collapse events. In analyses for waves, detection fake-reduction are different well-investigated ones a chirp analysis, because precise waveform templates not available. used an excess -power filter extraction candidates, developed two methods reduction fake events caused by nonstationary noises detector. These analysis were applied to real data...
A high-bandwidth density and low-power optical multichip module (MCM) is developed demonstrated. The includes bare driver chips an application specific integrated circuit bonded on waveguide-integrated organic carrier. Characterization results show that the I/O operates up to 20 Gb/s. high-speed performance not limited by electrical characteristics of carrier but chip bandwidth. space between VCSEL/PD surface waveguide minimized less than 5 μm using assembly technology with height control,...
The CLIO project including a 100 m baseline cryogenic gravitational wave laser interferometer and geophysical strain meter was conducted in the Kamioka mine Japan to investigate technical feasibility of large-scale telescope (LCGT), which is planned be constructed same with 30 times longer than CLIO, demonstrate collaborative operation between these instruments about long-term continuous signal veto analysis. About interferometer, whole vacuum system four cryostats, house cool sapphire...
Optical interconnect technology with a higher bandwidth density is required as the performance of high-end computer systems increases. In previous version our developed organic optical multi-chip modules, size fiber connectors limited density. To obtain bandwidth-density, we compact waveguide - which couple waveguides fibers in direction perpendicular to module surface. An assembly method established, and over 30 Gb/s operation for all channels transmitters receivers demonstrated.
We have investigated temporal fluctuation of superconducting qubits via the time-resolved measurement for an IBM Quantum system. found that qubit error rate abruptly changes during specific time intervals. Each high state persists several tens seconds and exhibits on-off behavior. The observed instability can be attributed to transitions induced by a stimulus. Resonant transition between fluctuating dressed states coupled with high-frequency resonators responsible error-rate change.
A large heat load caused by thermal radiation through a metal shield pipe was observed in cooling test of cryostat for prototype cryogenic interferometric gravitational wave detector. The approximately 1000 times larger than the value calculated Stefan–Boltzmann law. We studied this phenomenon simulation and experiment found that it conduction pipe.
We demonstrate a high-bandwidth density optical I/O on waveguide-integrated organic carrier. Each transmitter channel operates at data rate up to 20 Gb/s for an aggregate value of 240 Gb/s. High-speed and inter-channel crosstalk characterization show that the multi-chip module realizes over 10 times higher bandwidth than conventional fiber modules by chip-level packaging waveguide core pitch reduction, therefore supports nearly 2 Tb/s bandwidth.
Cryogenic Laser Interferometer Observatory (CLIO) is a laser interferometric gravitational wave detector using cryogenic cooled mirrors. In order to cool the mirrors, environment necessary. We made four vacuum chambers with shields inside. The mirror suspended by suspension system heat path for transferring from shield. Test cooling of and has been done. After one week cooling, was 8K 10K were at 21K successfully.
We analyze the data of TAMA300 detector to search for gravitational waves from inspiraling compact star binaries with masses component stars in range $1{M}_{\ensuremath{\bigodot}}--3{M}_{\ensuremath{\bigodot}}$. In this analysis, 2705 hours data, taken during years 2000--2004, are used event search. combine results different observation runs, and obtain a single upper limit on rate coalescence our Galaxy 20 per year at 90% confidence level. limit, effects various systematic errors such as...
We developed an automatic measuring device of birefringence inhomogeneity in synthetic sapphire substrates to evaluate their crystal quality suitable for laser interferometric gravitational wave (GW) detectors. The orientation the projection c-axis on a plane orthogonal beam was measured with accuracy 2 × 10−2 rad. phase retardation 7 10−4 rad, which equivalent 4 10−10 terms fluctuation refractive index samples 150mm thickness. reproducibility 1% both and retardation. meets requirements LCGT...
While the thermomechanical properties of sapphire make it an excellent candidate test mass for advanced laser interferometers, its optical quality is not well understood or controlled. We have studied results from high-resolution measurements scattering, absorption, and birefringence in test-mass samples to better understand issues quality. Samples show large-scale scattering structures clearly linked crystal-growth process. characterized by presence point defects significantly lower (except...
We developed a high speed, low power optical interconnect system using efficiency 1060 nm VCSEL. Clear eye diagrams are recorded at 10 Gbps with lower than 2 mA bias and 150 mVp-p modulation voltage.
When optical input/output is the essential signal path from one CPU, aggregate bandwidth will exceed 10 Tbps, which requires 500 channels at 20 Gbps. Since CPU mounted on a carrier, carrier has to have attachment points interface of carrier. Although can use side walls connect cables with large number channels, or more connectors are needed. We propose compact and rugged approach, where bottom area shared by electrical contacts in socket an optically enabled printed circuit board (PCB)....
We present a 60-micrometer pitch polymer waveguide array attached active optical flexible module which is useful for compact and high-channel count interconnect. fabricated this realized 20-Gbps signal transmission.
Get PDF Email Share with Facebook Tweet This Post on reddit LinkedIn Add to CiteULike Mendeley BibSonomy Citation Copy Text H. Hsu, M. Tokunari, and S. Nakagawa, "High-Bandwidth Optical I/O Link MCM," in Fiber Communication Conference, OSA Technical Digest (online) (Optica Publishing Group, 2015), paper W2A.51. Export BibTex Endnote (RIS) HTML Plain alert Save article
For efficient light coupling from and into an optical multi-chip module (MCM), the micro-lens array connector (MLAC) is developed. MLAC, composed of a waveguide side lens fiber connector, integrates 24 collimation micro-lense pairs in its small volume, realizing high bandwidth density, low loss, large alignment tolerance simple assembling process. In this paper, mechanical design characteristics MLAC are introduced. The criteria challenges processes also described.
Organic optical multi-chip modules for high bandwidth-density and low-power link in high-performance computing systems are developed. The light from polymer waveguide is coupled to a multimode fiber through total internal reflection (TIR) mirror newly-developed compact connector with lens arrays. For preventing UV adhesive assembly or an underfill resin optoelectronic chip goes into the TIR cavity, materials proper viscosity wettability tested. As result, 35 Gb/s operation achieved both...
Outgassing velocities and optical absorption coefficients of black colored absorbers (UB-NiP, Phosblack II, Raydent, ECB+DLC Alumite) were studied to reduce scattered strayed light in interferometric gravitational wave detectors. The measured results showed that the UB-NiP had largest coefficient 99.89% for 1064nm wavelength light. For outgassing velocity, lowest value, which was 1 × 10−8 Pam3/s/m2 at 20 hours. This value about two orders magnitude smaller than UB-NiP, however, its only 65...
We demonstrate an FPGA with 12-channel optical I/O on waveguide-integrated surface laminar circuit, highly-integrated multi-chip module. Each transmitter channel operates at data rate over 6 Gb/s.
The high-speed performance of polymer waveguide-based optical multi-chip module (MCM) link is demonstrated. Two MCMs serving as TX and RX respectively are connected by a graded-index multi-mode fiber. We integrated commercially-available 850-nm bare VCSEL PD chips on our custom-made MCM. operates at bitrate up to 14 Gb/s an open eye obtained 20 Gb/s.
The optical property of a large mirror substrate 250 mm in diameter was successfully measured at the required resolution to meet target sensitivity Large-Scale Cryogenic Gravitational Wave Telescope (LCGT) project. Although quality piece not sufficient achieve sensitivity, we could present how cope with crystal orientation for reducing any negative effect birefringence substrate, and also produce useful data manufacturers improve quality.
Assembly process reliability for Optical Multi-Chip Modules (MCM) is studied and improved. In the optoelectronic (OE) chip assembly MCM, OE with Au stud bump joined Sn-Ag-Cu (SAC) soldered in a through-waveguide via on an organic substrate to obtain high optical coupling efficiency. Since solid-liquid diffusion of molten SAC rapid, formation brittle intermetallic compounds such as AuSn4 observed by energy-dispersive X-ray analysis, result temperature dwell time should minimized. Furthermore,...
We have investigated temporal fluctuation of superconducting qubits via the time-resolved measurement for an IBM Quantum system. found that qubit error rate abruptly changes during specific time intervals. Each high state persists several tens seconds, and exhibits on-off behavior. The observed instability can be attributed to transitions induced by a stimulus. Resonant transition between fluctuating dressed states coupled with high-frequency resonators responsible error-rate change.