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:
Jun. 11, 2002
Filed:
Jul. 28, 1998
NEC Corporation, Tokyo, JP;
Abstract
An optical wavelength division coupler wavelength-divides a wavelength multiplexed light to respective wavelength lights each of which is dropped to an optical gate switch -i (i= ˜n) and a light receiver -i by an optical coupler -i and supplied to an optical light fault monitor through the light receiver -i. When the optical signal deterioration monitor detects an optical loss of wavelength (OLOW), an optical loss of signal (OLOS) or an optical signal degrade (OSD) in wavelength lights processed by the optical coupler -i as a fault detection signal in an optical layer, a controller controls the optical gate switch -i to cut off wavelength light passing therethrough and sends an optical alarm indication signal (AIS-O) to a downstream side. Therefore, when a loss of signal is detected by the light receiver -i, the optical signal deterioration monitor can know the alarm indication signal (AIS) from the upstream side, removing the necessity of special hardware therefor.