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. 29, 1991
Filed:
Mar. 31, 1989
Carl F Buhrer, Framingham, MA (US);
GTE Laboratories Incorporated, Waltham, MA (US);
Abstract
A quasi-achromatic configuration of two Faraday elements and five birefringent plates which when suitably oriented between two linearly polarizing elements would constitute an optical isolator or circulator. The nominal Faraday rotations of the two elements are 45.degree. and 90.degree. at a center design wavelength about which the devices are to operate. Changes in these rotations due to either wavelength or temperature variations compensate one another because of their coupling by the birefringent plates. In this way a higher degree of isolation is obtained over a wider optical bandwidth than would be possible in a device using a single 45.degree. Faraday element. A group of three plates is used between the two Faraday elements and two more follow them to give the required polarization transformations which must themselves be quasi-achromatic over the desired wavelength range.