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:
May. 06, 2003
Filed:
Aug. 18, 1999
Wei-Hong Chen, Hsinchu, TW;
Winston I. Way, Hsinchu, TW;
New Elite Technologies, Inc., Hsinchu, TW;
Abstract
An optical fiber transmitter, which consists of a modulated optical source, a pre-distortion circuit, a chirped-fiber grating, an optical circulator or a coupler, is designed to transport subcarrier multiplexed (SCM) signals over a long transmission distance. Here the SCM signals include: analog amplitude-modulated vestigial-sideband (AM-VSB) cable television signals, digital quadrature-amplitude-modulated (QAM) signals, or orthogonal-frequency-division-multiplexed (OFDM) signals, or quadrature-phase-shift-keyed (QPSK) signals, etc. on radio-frequency (RF) or microwave carriers, and/or digital wireless signals on RF, microwave or millimeter wave carriers. The modulated light source can be a directly modulated laser diode, or an external LiNbO3 modulator with a continuous wave (CW) laser diode as the source, or an external electro-absorption modulator with an integrated CW laser diode. The chirped fiber grating has a chromatic dispersion characteristic which is opposite to that of the output transmission path, so that the majority of nonlinear distortions and carrier suppression caused by the optical fiber dispersion in a long-distance system can be significantly reduced. The pre-distortion circuit is used to correct the residual nonlinear distortions and eliminate the residual carrier suppression effect, which cannot be completely eliminated by the chirped fiber grating. The pre-distortion circuit is also used to suppress the residual nonlinear distortions and carrier suppression effects caused by the chirped fiber grating itself.