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. 24, 2008
Filed:
Dec. 30, 2004
San-liang Lee, Taipei, TW;
Chun-liang Yang, Sansing Township, Yilan County, TW;
Pei-min Gong, Jhonghe, TW;
Dar-zu Hsu, Sigang Township, Tainan County, TW;
Ming-hsiao Yang, Kaohsiung, TW;
Yun-lung Chou, Hsinchu, TW;
San-Liang Lee, Taipei, TW;
Chun-Liang Yang, Sansing Township, Yilan County, TW;
Pei-Min Gong, Jhonghe, TW;
Dar-Zu Hsu, Sigang Township, Tainan County, TW;
Ming-Hsiao Yang, Kaohsiung, TW;
Yun-Lung Chou, Hsinchu, TW;
Industrial Technology Research Institute, Hsinchu, TW;
Abstract
An apparatus and a method for monitoring optical signal-to-noise ratio are provided. It can be applied in dense wavelength-division multiplexed networks to monitor the transmission quality of each optical channel. The apparatus comprises an optical circulator, a tunable optical filter, a dithering signal, a dithered reflector, and two photodiodes. It can be integrated on a single chip. The invention utilizes the dithering and reflection functions of the dithered reflector, and passes the signal and the noise through the tunable optical filter once and twice, respectively. When the tunable optical filter is scanning and filtering the whole spectrum, the signal and noise powers are measured by the two photodiodes, respectively. The OSNR for each optical channel is then calculated according to the signal and noise powers. It can monitor channel location, wavelength drift, and OSNR by including a wavelength locker to act as an optical channel analyzer.