Akihisa Tomita

TL;DR: Two GHz-clocked QKD links enable the world-first secure TV conferencing over a distance of 45km to be demonstrated and detection of an eavesdropper, rerouting into a secure path, and key relay via trusted nodes are demonstrated in this network.

TL;DR: In this article, a super-prism phenomenon was demonstrated at optical wavelength in photonic crystals with three-dimensional-periodic structure fabricated on Si substrate, where the incident-angle dependence including negative refraction and multiple beam branching was interpreted from highly anisotropic dispersion surfaces derived by photonic band calculation.

TL;DR: In this article, self-determining collimated light is generated in a photonic crystal fabricated on silicon and the divergence of the collimated beam is insensitive to that of the incident beam and much smaller than the divergence generated in conventional Gaussian optics.

TL;DR: The first observation of the modulational instability of light waves in dielectric material using a neodymium-doped yttrium aluminum garnet laser operated at 1.319 \ensuremath{\mu}m and single-mode optical fibers with anomalous group-velocity dispersion is reported.

TL;DR: In this paper, a novel secure communication network with quantum key distribution in a metropolitan area is reported, where different QKD schemes are integrated to demonstrate secure TV conferencing over a distance of 45km, stable long-term operation and application to secure mobile phones.