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:
Feb. 26, 2008
Filed:
Jun. 16, 2000
Hirotaka Kawai, Tokyo, JP;
Hiromitsu Umezawa, Tokyo, JP;
Isao Kojima, Tokyo, JP;
Hidenori Nakata, Tokyo, JP;
Teruhisa Sahashi, Tokyo, JP;
Hirotaka Kawai, Tokyo, JP;
Hiromitsu Umezawa, Tokyo, JP;
Isao Kojima, Tokyo, JP;
Hidenori Nakata, Tokyo, JP;
Teruhisa Sahashi, Tokyo, JP;
FDK Corporation, , JP;
Abstract
An optical attenuator with increased dynamic range and reduced temperature-dependence over the dynamic range. The optical attenuator has a Faraday rotational angle variable device which applies an external magnetic field to light polarized by a garnet crystal, and a polarizer and an analyzer disposed at the front and rear of the optical axis of the device. There is an angle x formed between the plane of polarization of the light incident to the garnet crystal and the magnetic field orthogonal to the optical axis, where an angle y is formed between the polarizer and the analyzer, and the angle x is set to satisfy {(−z/2)+90×n}−12<x<{(−z/2)+90×n}+12 (n=0, 1, 2 or 3), where z=y±90; z is the angle of rotation of the plane of polarization caused by the Faraday rotational angle variable device.