Kouichi Akahane

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We examine the timing dependence of nanophotonic devices based on optical excitation transfer via optical near-field interactions at the nanometer scale. We theoretically analyze the dynamic behavior of a two-input nanophotonic switch composed of three quantum dots based on a density matrix formalism while assuming arrival-time differences, or skew, between(More)
We theoretically and experimentally evaluated energy dissipation of nanophotonic devices based on energy transfer via near-field interactions and their interfaces with optical far-fields. The lower bound is about 10 4 times more energy-efficient than electronic devices. We also examined some fundamental differences between near-field-mediated optical energy(More)
To open up a 1-microm waveband for photonic transport systems, we developed a hybrid and harmonically mode-locked semiconductor laser (MLL) that can transmit return-to-zero (RZ) optical signals at data rates on the order of gigabits per second. A single-mode hole-assisted fiber (HAF) was also developed for use as a 1-microm waveband signal transmission(More)
In this study, we report the effect of the excitation of non-exciton components caused by broadband pulses on quantum beat oscillation. Using a spectrally controlled pump pulse, a long-lived oscillation is clearly observed, and the pump-power dependence shows the suppression of the dephasing rate of the oscillation. Our results from incoherent carrier(More)
We successfully designed and fabricated a high-conversion-gain 100-GHz photoreceiver integrated with a UTC-PD and a PHEMT amplifier for 92-GHz carrier photonic wireless communication. Then, in a demonstration of 92-GHz carrier, OFDM, 16-QAM photonic wireless communication, we confirmed that high data rate of 11.03-Gbps (bit error rate of(More)
Error-free Gbps-order high-speed optical data signal generation in a > 5.5-THz ultra-broad optical frequency bandwidth of the O-band was successfully demonstrated using a newly developed quantum dot electro-optic modulator integrated with a semiconductor optical amplifier.
This paper describes high-speed optical modulation and detection devices for radio-over-fibre (RoF) systems which can distribute millimetre-wave signals over optical fibres with low-loss, and RoF-based high-performance imaging systems which can be used for foreign object debris in runways or railways. High-speed and high-sensitivity photo-detection would be(More)
We would like to introduce Daiichi Sankyo's approach to developing cancer targeted medicines with special reference to the drug discovery strategy, global discovery activities and external research collaboration leading to generation of innovative drugs for cancer patients. We are developing 14 clinical projects for cancer treatment and three of them have(More)