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. 11, 2005
Filed:
Feb. 26, 2002
Yoshiki Yamauchi, Hiratsuka, JP;
Kouichi Fujisaki, Yokosuka, JP;
Akimasa Kaneko, Mito, JP;
Takashi Asaoka, Tokyo, JP;
Yoshihisa Sakai, Isehara, JP;
Yoshiki Yamauchi, Hiratsuka, JP;
Kouichi Fujisaki, Yokosuka, JP;
Akimasa Kaneko, Mito, JP;
Takashi Asaoka, Tokyo, JP;
Yoshihisa Sakai, Isehara, JP;
NTT Electronics Corporation, Tokyo, JP;
Nippon Telegraph and Telephone Corporation, Tokyo, JP;
Abstract
A part of a wavelength division multiplexed optical signal output from a multiplexing area is extracted as a check signal, and then the extracted signal is guided to a multiplexing area. A reentered check signal is detected at a facet located opposite a facet from which the check signal has been reentered, and the state of the detected check signal is determined. Furthermore at need, on the basis of the result of the determination, a control signal is output that controls operations of a plurality of optical signals input to the multiplexing area.