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:
Nov. 25, 1997
Filed:
Aug. 10, 1995
Shinji Iwatsuka, Oamishirasato-machi, JP;
Yoichi Kanagawa, Narita, JP;
Kenjiro Hata, Matsudo, JP;
Makoto Sekijima, Ichikawa, JP;
TDK Corporation, Tokyo, JP;
Abstract
In an optical isolator including first and second birefringent plates whose optical axes are angularly different and a Faraday rotator inserted therebetween having a Faraday rotation angle of .theta..sub.f, (1) the angles of the optical axes of the first and second birefringent plates are so set that a forward incident polarized light passes through the first and second birefringent plates both as ordinary lights or both as extraordinary lights, and the relationship .theta..sub.f +.phi..sub.eff =90.degree. is satisfied when an actually used incident polarized light is incident in an oblique direction, or (2) the angles of the optical axes of the first and second birefringent plates are so set that a forward incident polarized light passes through one of the first and second birefringent plates as an ordinary light and the other birefringent plate as an extraordinary light, and the relationship .theta..sub.f -.phi..sub.eff =0.degree. is satisfied. Alternatively, cases when the magnetization of the Faraday rotator is reversed are compared and the direction of the magnetization which satisfies (1) and (2) as close as possible is selected. A good isolation is obtained by the present invention.