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. 13, 2002
Filed:
Jul. 26, 2000
Korea Advanced Institute of Science and Technology, Taejun, KR;
Abstract
The optical signal-to-noise ratio (OSNR) of optical signals that are demultiplexed into a plurality of optical channels by a wavelength-division multiplexing (WDM) optical transmission system is monitored by an apparatus which outputs the optical signals of each optical channel on a first path and a second path, and measures the signal intensity of each of the optical signals on the first path. The apparatus selectively passes an AC component of each of the optical signals on the second path and processes the AC component by converting the AC component into a digital signal and performing a fast fourier transform on the digital signal. The apparatus measures the noise intensity of the processed AC component on the second path. The OSNR of each optical signal is calculated by comparing the measured signal intensity of each of the optical signals and the measured noise intensity of the processed AC component of each of the optical signals.