Hiroyuki Kusaka

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A low-loss high-speed silicon in-phase (I) quadrature (Q) modulator is designed, fabricated and characterized. The fabricated IQ modulator has a low passive optical loss of 9 dB in C and L bands. Using the modulator, differential quadrature phase-shift keying (DQPSK) transmission at 44.6 Gb/s with differential detection is confirmed with an optical(More)
The 11-Gbps 80-km transmission performance of a zero-chirp silicon Mach-Zehnder modulator has been characterized. The zero-chirp characteristic of the silicon modulator is confirmed in the constellation measurement, and gives high tolerance both for positive and negative chromatic dispersion. A low-dispersion-penalty transmission up to 80 km using the(More)
a r t i c l e i n f o a b s t r a c t Results are presented from a study designed to evaluate the impact upon urban area transport and dispersion (T&D) modeling accuracy by coupling a microscale computational fluid dynamics (CFD) model with a mesoscale numerical weather prediction (NWP) model. The CFD model taking part in the evaluation was the CFD-Urban(More)
OBJECTIVES We aimed to identify the effect of environmental factors on sleep in the summertime in Japan. METHODS A self-reported questionnaire survey was conducted in Japan. Age of participants ranged from 20 to 70 years. RESULTS The mean Pittsburgh Sleep Quality Index (PSQI) score was 4.9 (±2.7), and 123 (35.0%) participants had scores of >5. According(More)
Following the heatstroke prevention guideline by the Ministry of Health, Labor, and Welfare of Japan, "safe hours" for heavy and light labor are estimated based on hourly wet-bulb globe temperature (WBGT) obtained from the three-member ensemble multi-period (the 2000s, 2030s, 2050s, 2070s, and 2090s) climate projections using dynamical downscaling approach.(More)
Oxidized pyrimidines are mainly repaired by base excision repair, which is initiated by damage-specific DNA glycosylases. NEIL1, the mammalian homolog of Escherichia coli endonuclease VIII and a major DNA glycosylase, initiates repair of oxidized pyrimidines. Here, we investigated the expression of two putative variant mouse NEIL1 (mNEIL1) mRNAs--variant 1(More)
Silicon photonic waveguides are promising in small-footprint low-cost monolithic photonic integrated circuits with capability of high-yield mass production using large-diameter wafers. Design, fabrication and performance characterization of a small-footprint monolithic dual-polarization quadrature phase-shift keying silicon-based optical modulator for(More)
We present a low-loss and small-footprint polarization rotator based on mode evolution. The polarization rotator is composed of an asymmetric-rib waveguide and a tapered waveguide, both of which consist only of a silicon core and a silica cladding. The rotator is fabricated under the same design rules as other device blocks, such as rib-waveguide phase(More)
SUMMARY 20-Gbps non return-to-zero (NRZ) — binary phase shift keying (BPSK) using the silicon Mach-Zehnder modulator is demonstrated and characterized. Measurement of a constellation diagram confirms successful modulation of 20-Gbps BPSK with the silicon modulator. Transmission performance is characterized in the measurement of bit-error-rate in accumulated(More)
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