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:
Jan. 04, 2011
Filed:
Oct. 04, 2007
Applicant:
Tatsuya Tomaru, Hatoyama, JP;
Inventor:
Tatsuya Tomaru, Hatoyama, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04L 9/12 (2006.01); H04B 10/00 (2006.01); H04B 10/04 (2006.01); H04B 10/06 (2006.01);
U.S. Cl.
CPC ...
Abstract
Regardless of a transmission basis, a phase of a signal light with reference to a phase of local light is measured, and an output light from an antisqueezed light source in a transponder device is modulated in accordance with the measured phase. Since information obtainable in the transponder device is only the relative phase of the signal light with reference to the phase of the local light, and includes fluctuations corresponding to an antisqueezed component of the signal light, even if the information in the transponder device is eavesdropped on, the information cannot be decoded easily.