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.:

US 7706695 B1

PDF
Full Text
Expired
Date of Patent:
Apr. 27, 2010

Filed:

Jun. 28, 2006
Applicants:

Kazuo Hironishi, Kawasaki, JP;

Takeshi Hoshida, Kawasaki, JP;

Inventors:

Kazuo Hironishi, Kawasaki, JP;

Takeshi Hoshida, Kawasaki, JP;

Assignee:

Fujitsu Limited, Kawasaki, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04B 10/04 (2006.01); H04B 10/06 (2006.01);
U.S. Cl.
CPC ...
Abstract

An interferometer comprises a delay element and a phase shift element. The delay element delays an optical DQPSK signal by one-symbol time. The phase shift element shifts the optical DQPSK signal by π/8. A pair of photodiodes converts each of a pair of optical signals output from the interferometer into an electric signal. A photodetector circuit converts differential current obtained by a pair of the photodiodes into voltage and outputs as a detection signal. A first decision circuit outputs one-bit information based on the voltage of the detection signal. A second decision circuit outputs one-bit information based on a squared value of the voltage of the detection signal.


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Hironishi, Kazuo. (2010). Optical dqpsk receiver apparatus (U.S. Patent No. 7706695). U.S. Patent and Trademark Office. https://idiyas.com/patent/badge/7706695

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