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We investigated wavelength-control-characteristics of a silicon photonic transmitter employing heater-integrated silicon micro-ring-modulator and flip-chip integrated CMOS driver. A novel wavelength control successfully demonstrated error-free operation at 25 Gbps during wide-package-temperature cycle between 20 and 60ºC for the first time.
An 8-wavelength light source for silicon WDM transceiver was developed using an AlGaInAs DFB laser array integrated with tapered-SOA and precise flip-chip bonding technology. The device demonstrated high Si-waveguide-coupled output powers of >+2.3dBm/ch under 8-ch simultaneous operation at 70°C.
Wide field-of-view (FoV) MKID cameras for millimeter and sub millimeter astronomy have been developed at the Advanced Technology Center of NAOJ. To observe large scale structure of the universe, thousands of pixels with high sensitive detectors are required. We demonstrate key technologies, such as 700 pixel 220 GHz MKID camera, Si lens array, anti-reflection (AR) coating for Si and Alumina lens,...
A four-wavelength Si/III-V hybrid laser array was developed for energy-efficient silicon photonics CWDM transmitter. Under 4-ch simultaneous operation, stable lasing oscillations at four neighboring ring-resonator peaks are obtained with high output powers of >+5dBm/ch.
A modulator with an enhanced efficiency by cascaded microring resonators (MRRs), and a single-mode laser with a wavelength determined by a MRR wavelength filter were integrated on a Si chip to demonstrate for the first time wavelength-tuning-free 10-Gb/s modulation over a wide range of temperature.
A highly-efficient, low-noise optical source consisting of a Si micro-ring resonator (MRR) and a semiconductor optical amplifier (SOA) has been developed. A MRR-based modulator integrated with the optical source exhibited a temperature control free 10 Gbps modulation over a wide temperature range.
In order to develop a data center power efficiency index, we built a test bed of a data center and measured power components and environmental variables in some detail, including the power consumption and temperature of each node, rack and air conditioning unit, as well as load on the CPU, Disk I/O and the network. In these measurements we found that there was a significant imbalance of CPU temperatures...
This paper proposes a new method for improving direct prediction scheme that has been employed in conventional video coding standards such as AVC/H.264. We extend direct prediction concept to achieve better adaptation to local statistics of video source with the assumption of the use of larger motion blocks than conventional macroblock size. Firstly, our direct prediction method introduces block adaptive...
We report effective all-optical multicast wavelength conversion exploiting cross gain modulation (XGM) in a QD-SOA. 80 Gb/s multi-conversion on four 400 GHz spaced wavelengths is demonstrated with moderate Q2 factor penalty.
We report recent results about all-optical processing using QD-SOAs. Those include 160 Gb/s wavelength conversion by XGM and regenerative amplification up to 80 Gb/s obtained thanks to limiting amplification and detuned filtering of SPM.
A less temperature dependent columnar-quantum-dot semiconductor optical amplifier (CQD-SOA) with high efficiency is developed. At 50??C, a high penalty-free output power of ~12 dBm together with a high gain of 17 dB is successfully demonstrated.
We demonstrate 172-Gbps cascaded OTDM MUX and DEMUX for future LAN applications. Challenge is that the key devices are integratable, i.e. ISBT optical gates, EAM-DFB VSR MSA transceivers, quantum-dot SOAs, and mode-locked laser diodes.
We report regenerative amplification of 10, 40 and 80 Gb/s return-to-zero (RZ) signals in a columnar quantum dot SOA (CQD-SOA). Self-phase-modulation (SPM) with a red-shifted band-pass filter and limiting amplification are exploited.
The understanding of H diffusion in materials is pivotal to designing suitable processes. Though a nudged elastic band (NEB)+molecular dynamics (MD)/quantum mechanics (QM) algorithm has been developed to simulate H diffusion in materials by our group, it is often not computationally feasible for large-scale models on a conventional single system. We thus gridify the NEB+MD/QM algorithm on the top...
IaaS (Infrastructure-as-a-Service) is an emerging concept of cloud computing, which allows users to obtain hardware resources from virtualized data centers. Although many commercial IaaS clouds have recently been launched, dynamic virtual machine (VM) migration is not possible among service providers; users are locked into a particular provider, and cannot transparently relocate their VMs to another...
We report, for the first time, pattern-effect free wavelength conversion in a QD-SOA at 160 Gb/s in C-band. Very fast (10ps) 85% gain recovery and the use of a slightly detuned blue-shifted filter allow highly efficient XGM wavelength conversion.
To ensure large-scale and long-time (LSLT) applications to run smoothly in a dynamic and heterogeneous grid environment, we have designed and implemented a WSRF-based framework with which users can reserve resources and request on-demand computing resources. The framework can be architecturely divided into three tiers: the tier providing client-side reservation and allocation APIs, the tier for reservation...
The authors have been leading the GEO Grid project since 2005. This project is primarily aiming at providing an e-Science infrastructure for the worldwide Earth Sciences community. The GEO Grid is designed to virtually integrate all relevant data as a VO-enabled service based on Grid technology, and as such, is accessible as a set of services. This kind of infrastructure is demanded not only by geoscience,...
In order to guarantee large-scale and long-time applications to execute smoothly in a dynamic and heterogeneous grid environment, we have designed and implemented a framework by which users can reserve and allocate on- demand resources, and manage their jobs from within grid- enabled applications. This framework is based on a three- tier architecture that consists of client API, centralized broker...
A GridFMO application was developed by recoining the fragment molecular orbital (FMO) method of GAMESS with grid technology. With the GridFMO, quantum calculations of macro molecules become possible by using large amount of computational resources collected from many moderate-sized cluster computers. A new middleware suite was developed based on Ninf-G, whose fault tolerance and flexible resource...
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