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. 24, 2002
Filed:
Aug. 10, 2000
Reich Watterson, Lexington, MA (US);
Parviz Tayebati, Boston, MA (US);
Don McDaniel, North Andover, MA (US);
Kevin McCallion, Boston, MA (US);
CoreTek, Inc., Wilmington, MA (US);
Abstract
A compact wavelength monitoring and control assembly for a narrow band (i.e., laser) source is provided, comprising two narrow bandpass, wavelength selective transmission filter elements of Fabry-Perot structure through which two separate collimated beams from a laser source are directed onto two photodetectors. The spacing of the multiple transmission maxima for one etalon is chosen to match that of the desired set of frequencies to be used for locking purposes. The spacing of the transmission maxima for the second etalon is used, in combination with a dielectric filter, to generate a wavelength fiducial to denote an absolute frequency. The spacing of the second etalon is chosen to be much wider than the frequency grid etalon. A control circuit processes the simultaneously acquired signals from the two detectors as the laser wavelength is varied. The device functions as an optical wavelength discriminator in which the detectors convert optical energy to current (or voltage) for a feedback loop for controlling the laser source. Any one of a large number of discrete, predetermined wavelengths may be chosen for locking using the same device. The system is compact and may be packaged within the same temperature controlled laser assembly for maximum performance and minimum circuit board space requirements.