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:
May. 13, 2008
Filed:
Oct. 08, 2004
Izumi Kawata, Sagamihara, JP;
Zhigang Peng, Ebina, JP;
Akio Mukai, Machida, JP;
Asahi Kasei Microsystems Co., Ltd., Tokyo, JP;
Abstract
A semiconductor laser wavelength control device capable of controlling the optical wavelength constant even if the optical output intensity of the semiconductor laser varies and permitting a reduction in overall size is to be provided. It is provided with control means which controls the optical wavelength of a laser diodeto a prescribed wavelength by driving a temperature control unit to control the temperature of the laser diode. The control means has a low pass characteristic, with a first photo electric conversion signal resulting from the conversion of light having passed an optical filterinto an electric signal and a target for the laser diodeto emit light of a prescribed wavelength being entered as inputs, supplies a control signal for driving the temperature of the temperature control unit, and is set that a greater one out of a plurality of poles has a higher frequency than the cut-off frequency fand the zero point has a lower frequency than the cut-off frequency fof the object of control.