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:
Apr. 03, 2012
Filed:
Dec. 27, 2007
Yusuke Nasu, Atsugi, JP;
Manabu Oguma, Atsugi, JP;
Yasuaki Hashizume, Yokosuka, JP;
Yasuyuki Inoue, Atsugi, JP;
Hiroshi Takahashi, Atsugi, JP;
Kuninori Hattori, Atsugi, JP;
Toshikazu Hashimoto, Atsugi, JP;
Yohei Sakamaki, Atsugi, JP;
Yusuke Nasu, Atsugi, JP;
Manabu Oguma, Atsugi, JP;
Yasuaki Hashizume, Yokosuka, JP;
Yasuyuki Inoue, Atsugi, JP;
Hiroshi Takahashi, Atsugi, JP;
Kuninori Hattori, Atsugi, JP;
Toshikazu Hashimoto, Atsugi, JP;
Yohei Sakamaki, Atsugi, JP;
Nippon Telegraph and Telephone Corporation, Tokyo, JP;
Abstract
In an optical interferometer, polarization dependence attributable to the optical path difference has conventionally been eliminated by inserting a half-wave plate at the center of the interferometer. However, light induced by polarization coupling produced in directional couplers used in the optical interferometer causes interference having different interference conditions from those of the normal light. Polarization rotators that effect any one of 90° rotation and −90° rotation of all states of polarization of incoming light are inserted in the optical interferometer, and thereby the interference conditions of light induced by polarization coupling are made the same as those of the normal light. Each of the polarization rotators is implemented by using two half-wave plates and by varying an angle of combination of these half-wave plates. Alternatively, each of the polarization rotators is implemented through a combination of one half-wave plate and a waveguide having birefringence properties.