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:
Aug. 08, 1989
Filed:
Jun. 29, 1987
Friedemann Mohr, Renningen, DE;
Alcatel N.V., Amsterdam, NL;
Abstract
Optical heterodyne receivers for ASK-, PSK-, FSK-, and DPSK-modulated signals are disclosed which contain a polarization controller. The receiver contains a unit (Q, Q') which works on the difference-detector principle to eliminate the shot noise of the local oscillator (LO), which emits circularly polarized light. It further includes a quadrature demodulator (D, D', D') which, besides delivering the useful signal (N), provides polarization control signals (S.sub.E, S.sub.W) with which the ellipticity and the polarization angle of the received light (E.sub.S) are adjusted in such a way that the received light (E.sub.S) is linearly polarized at an angle of 45.degree. or 135.degree..