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:
Sep. 07, 1993
Filed:
Nov. 05, 1991
Hermann Gysel, San Jose, CA (US);
Mani Ramachandran, San Jose, CA (US);
Synchronous Communications, Inc., San Jose, CA (US);
Abstract
An electrical compensation circuit and an optical compensation circuit are provided for compensating for expansion-type and compression-type gain distortion due to the interaction of a laser and an optical amplifier. In the electrical compensation circuit there is provided a linear signal path and a nonlinear signal path. A delay circuit in the linear signal path compensates for a signal delay in the nonlinear signal path. In the nonlinear signal path there is provided an FET and a transformer. A modulation signal applied to the linear signal path and the nonlinear signal path is processed in the nonlinear signal path and combined with the signal in the linear signal path so as to provide a predistorted modulation signal which is substantially equal in amplitude and opposite in phase to the gain distortion in the optical signal at the output of the optical amplifier. In the optical compensation circuit there is provided a predetermined length of erbium-doped fiber which is inserted between a laser and an erbium-doped fiber amplifier (EDFA) so as to provide an absorption of the output of the laser which is equal in magnitude and opposite in phase to the gain distortion in the output signal of an uncompensated EDFA.