The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 02, 2025
Filed:
Jan. 24, 2022
Nec Corporation, Tokyo, JP;
National Institute of Information and Communications Technology, Koganei, JP;
National University Corporation Hokkaido University, Sapporo, JP;
The University of Tokyo, Tokyo, JP;
Ken-Ichiro Yoshino, Tokyo, JP;
Mikio Fujiwara, Tokyo, JP;
Akihisa Tomita, Hokkaido, JP;
Masato Koashi, Tokyo, JP;
Masahiro Takeoka, Tokyo, JP;
Masahide Sasaki, Tokyo, JP;
NEC CORPORATION, Tokyo, JP;
NATIONAL INSTITUTE OF INFORMATION AND COMMUNICATIONS TECHNOLOGY, Koganei, JP;
National University Corporation Hokkaido University, Sapporo, JP;
THE UNIVERSITY OF TOKYO, Tokyo, JP;
Abstract
An object is to prevent eavesdropping in quantum key distribution. A photon detector outputs an output current indicating a result of detecting a quantum signal. A current-voltage conversion unit converts the output current into an output voltage signal. An analog-to-digital converter outputs an output voltage signal obtained by analog-digital conversion of the output voltage signal. A signal processing unit performs predetermined signal processing on the output voltage signal, and outputs a photon detection signal indicating a result of detecting the quantum signal. When a time difference between a timing at which the quantum signal is incident into the photon detector and a reference timing determined based on a clock signal is not within a determination range, the photon detection signal is not output from the signal processing unit.