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:
Jul. 25, 1995
Filed:
May. 09, 1994
Toshibumi Kawano, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
In an optical repeatered transmission system, an optical multiplex of a data signal and a supervisory signal is sent from a first terminal station. At an upstream repeater station, the optical signal is received and combined with excitation light energy supplied from a laser and amplified by an erbium-doped fiber with the excitation energy for transmission to a downstream repeater station. At the downstream repeater station, the optical signal is combined with excitation light energy supplied from a laser and amplified by an erbium-doped fiber with the excitation energy for transmission to a second terminal station. At the upstream repeater station, the supervisory signal is monitored. If it is determined to be lost, the excitation light energy of the station is modulated with a first fault-point indicating signal which is unique to the upstream repeater station and transmitted to the downstream repeater station instead of the optical multiplex signal. At the downstream repeater station, the supervisory signal and the first fault-point indicating signal are monitored. If both of these signals are determined to be lost, the excitation energy of the station is modulated with a second fault-point indicating signal that is unique to the downstream repeater station and transmitted to the second terminal station. If the supervisory signal and any of the fault-point indicating signals are not detected, an alarm is given indicating that a failure has occurred between the second terminal station and the downstream repeater station. If one of the fault-point indicating signals is detected, an alarm will be given indicating that a failure has occurred at a point identified by the detected fault-point indicating signal.