378 citations · 1.3k across the 23 of their papers we have counts for
4 papers · 2 filters
Experimental investigation of pulsed entangled photons and photonic quantum channels
Yoshihiro Nambu, Koji. Usami, Akihisa Tomita +5
The development of key devices and systems in quantum information technology, such as entangled particle sources, quantum gates and quantum cryptographic systems, requires a reliab…
A New Strategy of Quantum-State Estimation for Achieving the Cramer-Rao Bound
Koji Usami, Yoshihiro Nambu, Yoshiyuki Tsuda +2
We experimentally analyzed the statistical errors in quantum-state estimation and examined whether their lower bound, which is derived from the Cramer-Rao inequality, can be truly…
A balanced gated-mode photon detector for qubit discrimination in 1550 nm
Akihisa Tomita, Kazuo Nakamura
A photon detector combining the two avalanche photon diodes (APD) has been demonstrated for qubit discrimination in 1550 nm. Spikes accompanied with the signals in gated-mode were…
Generation of polarization-entangled photon pairs in a cascade of two type-I crystals pumped by femtosecond pulses
Y. Nambu, K. Usami, Y. Tsuda +2
We report the generation of polarization-entangled photons by femtosecond-pulse-pumped spontaneous parametric down-conversion in a cascade of two type-I crystals. Highly entangled…