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:
Apr. 20, 2004
Filed:
Jan. 29, 2001
Yasuhiro Koike, Yokohama, JP;
Takeshi Ota, Tokyo, JP;
Abstract
An optical transmitter-receiver that does not have a harmful effect on the human eye when an optical fiber is disconnected from the apparatus and is able to determine easily when the fiber has been reconnected. A normal signal detector and a dummy signal detector determine when a signal from another optical transmitter-receiver is no longer received due to disconnection of an optical fiber. This result switches an output switch and causes a second reference voltage to be transmitted to an optical output automatic controller, thereby reducing the power of a laser diode. At the same time, a signal switch provides a dummy signal having a low frequency to the laser diode in place of the normal signal, resulting in output of a dummy optical signal. At this time, the other optical transmitter-receiver also outputs a dummy optical signal. When the optical fiber is reconnected, the dummy signal transmitted from the other optical transmitter-receiver is detected. Upon detection, the output of the laser diode is set to a normal high value, and a normal signal is output.