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:
Dec. 08, 1992
Filed:
Jun. 14, 1991
Applicant:
Inventor:
Timothy A Large, Papworth Everard, GB;
Assignee:
Northern Telecom Limited, Montreal, CA;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04B / ;
U.S. Cl.
CPC ...
359192 ; 359189 ;
Abstract
A transmitted (TX) signal received from the remote location is mixed in a polarization resolving beam splitter (10) with a local oscillator (LO) signal from a laser (15). The LO and TX signal components emerging from the beam splitter (10) are orthogonally polarized, but their polarization states are brought into alignment by passage through two birefringent elements (19, 20) before falling on two photodetectors (17, 18). Adjustment of a polarization controller (16) ensures that approximately equal LO power falls on each photodetector.