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:
Jul. 02, 2002
Filed:
Jun. 02, 1999
Kazutaka Masuzawa, Tokyo, JP;
Mikio Aoki, Tokyo, JP;
Taiyo Yuden Co., Ltd., Tokyo, JP;
Abstract
In a transmission section ( ), a light-emitting element ( ) is driven by a digital signal (DS ) serving as an object of transmission, light emitted from the light-emitting element ( ) is split by a beam splitter ( ) into two linearly polarized light components which are orthogonal to each other, and the linearly polarized light components are radiated by ¼-wavelength plates ( A and C) into the air as circularly polarized light components having the same rotating direction. In a reception section ( ), the circularly polarized light components radiated from the transmission section ( ) and circularly polarized light components having a reverse rotating direction are received by two different light-receiving elements ( A and B), and the difference of the levels of two electric signals output from the two light-receiving elements ( A and B) is calculated by a subtraction circuit ( ), so that a digital signal serving as an object of transmission is obtained by removing a disturbance noise component. With this arrangement, an optical digital communication apparatus which can reduce influence of disturbance optical noise, improve an S/N ratio, and extend a communication distance.