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:
Jan. 11, 2011
Filed:
Dec. 07, 2006
Joon Ki Lee, Daejeon, KR;
Jyung Chan Lee, Daejeon, KR;
Kwangjoon Kim, Daejeon, KR;
Electronics and Telecommunications Research Institute, Daejeon, KR;
Abstract
Provided are an apparatus and method for maintaining an constant extinction ratio of a laser diode (LD). The apparatus includes: an automatic power control circuit maintaining the constant optical power of the LD; a correlation deriver deriving correlations between a bias current of the LD and a modulation current to maintain the constant extinction ratio of the LD; and a modulation current control circuit controlling the modulation current to maintain constant the extinction ratio of the LD based on the correlations. The apparatus and method do not use a temperature sensor but derive a relationship between variances of a bias current of the LD and a modulation current according to temperature change, control the modulation current based on the relationship, and maintain the constant extinction ratio of the LD.