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:
Aug. 09, 2011
Filed:
May. 19, 2006
Mikio Yoneyama, Tokyo, JP;
Fumiaki Saitou, Yokohama, JP;
Shigeru Ono, Fussa, JP;
Yosuke Takeuchi, Yokosuka, JP;
Kazushige Yonenaga, Yokosuka, JP;
Shoichiro Kuwahara, Yokosuka, JP;
Eiji Yoshida, Yokosuka, JP;
Yutaka Miyamoto, Tokyo, JP;
Hiroto Kawakami, Yokosuka, JP;
Mikio Yoneyama, Tokyo, JP;
Fumiaki Saitou, Yokohama, JP;
Shigeru Ono, Fussa, JP;
Yosuke Takeuchi, Yokosuka, JP;
Kazushige Yonenaga, Yokosuka, JP;
Shoichiro Kuwahara, Yokosuka, JP;
Eiji Yoshida, Yokosuka, JP;
Yutaka Miyamoto, Tokyo, JP;
Hiroto Kawakami, Yokosuka, JP;
NTT Electronics Corporation, Tokyo, JP;
Nippon Telegraph and Telephone Corporation, Tokyo, JP;
Abstract
The present invention relates to an optical receiver, in which the transmittance of a Mach-Zehnder interferometer can be locked at a normal operation point in a simple structure and control. A transmittance detecting circuit and a minute modulation signal detecting circuit are provided in parallel after a balanced optical receiver, and a switch is selectively connectable either a minute modulation signal detecting circuit and a transmittance detecting circuit. In the initial stage of frequency pull-in, the switch is set to connect the transmittance detecting circuit to the synchronous detection circuit. If the transmittance detecting circuit detects that the transmittance of the Mach-Zehnder interferometer at the carrier frequency becomes a desired transmittance, the connection of the switch is switched from the transmittance detecting circuit to the minute modulation signal detecting circuit.