Abstract: A method and apparatus is provided for compensating for dispersion in a wavelength division multiplexed (WDM) optical communication system. The system includes a transmitting and receiving terminal for transmitting and receiving, respectively, an optical signal having a plurality of channels, and an optical fiber transmission path coupling the first and second terminals. The fiber transmission path has a dispersion substantially equal to zero for a selected channel, positive dispersion for a first set of channels, and negative dispersion for a second set of channels. The method begins by providing positive dispersion compensation to the second set of channels at one of the terminals. Negative dispersion compensation is provided to the first set of channels, also at one of the terminals.

Abstract: A technique employing a depolarized optical source to reduce the polarization dependent gain associated with the optical pump signal used to excite doped fiber amplifiers within an optical transmission system. Pumping the doped fiber amplifiers with a signal that has no single predominant linear SOP, equalizes the gain of the amplifiers. A particular embodiment of the invention includes a pump comprised of a passive polarization scrambler coupled to the output of a multifrequency optical laser. The simple, passive arrangement keeps overall system costs to a minimum and increases reliability.

Abstract: A technique for reducing signal degradation and fading within a long optical transmission by utilizing a rotating waveplate arrangement to rotate the SOP of an optical signal launched into the transmission system, and thereby minimize polarization dependent hole-burning ("PDHB"). This effectively reduces the degree of polarization of the launched optical signal, without degrading the noise and dispersion characteristics of the signal. The rate of waveplate rotation is chosen to ensure that the SOP of the launched signal does not remain at a particular SOP long enough to anisotropically saturate any optical amplifier employed within the transmission system, and give rise to PDHB.

Abstract: A technique for reducing signal degradation and fading within a long optical transmission system by minimizing polarization dependent hole-burning ("PDHB") through the cyclic stressing of a birefringent optical fiber to modulate the SOP of an optical signal launched into the transmission system. This effectively reduces the degree of polarization of the launched optical signal, without degrading the noise and dispersion characteristics of the signal. The modulation frequency of the SOP is chosen to ensure that the launched signal does not remain at a particular SOP long enough to anisotropically saturate any optical amplifier employed within the transmission system, and give rise to PDHB.