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:
Dec. 03, 2002
Filed:
Jul. 03, 2000
Nobuhisa Nishioki, Ibaraki, JP;
Kiyokazu Okamoto, Ibaraki, JP;
Mitutoyo Corporation, Kawasaki, JP;
Abstract
A part of the output light from a semiconductor laser ( ), which has a wavelength controllably variable with an injection current, is split at a beam splitter ( ) and introduced into a interference optical system ( ). In order to vary an optical path length difference between two light beams in the interference optical system ( ) to modulate interference fringes to be obtained, AOMs ( ) are arranged on the two split optical paths and an EOM ( ) on one of them. The interference fringes obtained from the interference optical system ( ) are received at a photoreceptive device ( ), and from the received signal, the phase is detected by a phase detector ( ) and the phase amplitude is detected by an amplitude extractor ( ). In order to stabilize the wavelength, a controller ( ) feedback controls the injection current to the semiconductor laser ( ) so that the phase amplitude matches to a predetermined setting.