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:
Nov. 02, 2004
Filed:
Jan. 24, 2001
Yun Chur Chung, Taejon, KR;
Chul Han Kim, Kyungki-do, KR;
Dae Kwang Jung, Kyungsang-namdo, KR;
Jun Hang Lee, Kyungki-do, KR;
Teralink Communications, Inc., Daejeon, KR;
Abstract
The present invention relates to a method and apparatus for automatically monitoring an optical signal-to-noise ratio in which an arbitrarily polarized optical signal including an unpolarized ASE noise is inputted to a rotating quarter-wave plate and then to a rotating linear polarizer so that a maximum power and a minimum power of the signal outputted from the rotating linear polarizer can be detected, and the detected maximum power and minimum power is used for automatically monitoring the optical signal-to-noise ratio. The method for monitoring the optical signal-to-noise ratio (OSNR) using a polarization-nulling method, comprises the steps of: (a) linearly polarizing an arbitrarily polarized optical signal including an unpolarized ASE noise; (b) separating the optical signal and the ASE noise from the linearly polarized optical signal including the unpolarized ASE noise to measure a power of the optical signal and a power of the ASE noise included in a bandwidth of an optical signal; and (c) obtaining the optical signal-to-noise ratio (OSNR) using the measured optical signal power and ASE noise power.