Abstract: A system, method and apparatus for monitoring impairment related parameters such as Q factor within an all-optical system by using forward error correction (FEC) to derive a bit error rate (BER), which BER is used to determine the impairment related parameters.

Abstract: The invention comprises a method and apparatus for passive optical conditioning and format conversion of RZ optical signals including, but not limited to, conversion from RZ to CRZ or to CSRZ, using a nonlinear device. The invention generates signals that may be optimized to improve transmission performance, receiver performance, and/or spectral efficiency of the optical transmission system. A method for passively generating an optical carrier-suppressed return-to-zero (CSRZ) signal according to the present invention includes, propagating an optical RZ signal through a nonlinear element, the nonlinear element configured to broaden the optical RZ signal such that the optical RZ signal is phase shifted by approximately 3Π/2.

Abstract: Embodiments of the invention include system for monitoring the effectiveness of pulse shaping in a nonlinear optical fiber (40). The spectral content of the pulse, after passing through the nonlinear fiber (40), provides an indication of how effectively the pulse was regenerated. A portion of the pulse exiting the nonlinear fiber is tapped off and its pulse energy is measured in at least one selected spectral region. The selected spectral region is one in which the pulse tends to gain energy when effective regeneration is taking place. The information concerning the effectiveness of pulse shaping in a nonlinear optical fiber is fed back to dynamically change the residual dispersion at the regenerator input. The spectral measurement leads to a control signal (48) to indicate a level of performance of the system, or to improve the performance of the system by adjusting an operational parameter.

Abstract: The present invention generally provides optical signal transmission system having an optical signal source, at least one optical signal regenerator in series communication with the optical signal source via an optical signal communications medium, a dispersion module in series communication with the at least one optical signal regenerator via the optical signal communications medium, and a receiver in serial communication with the dispersion module via the optical signal communications medium. The dispersion compensation module inserts an amount of lumped dispersion into the system, which operates to improve the signal transmission characteristics.

Abstract: A method, apparatus and system for reducing gain ripple in a Raman-amplified WDM system includes determining a gain profile of an optical signal transported via a first Raman amplification span in a Raman-amplified WDM system, comparing the determined gain profile to a gain profile of an optical signal transported via a second Raman amplification span, determining, from the comparison, an amount of wavelength adjustment required for a plurality of Raman pumps comprising at least one Raman pump block of the second Raman amplification span to alter the gain profile of an optical signal transported via the second Raman amplification span, such that a cumulative gain profile of an optical signal transported via the first and the second Raman amplification spans approaches a desired gain profile, and generating a control signal suitable for adjusting the wavelengths of the plurality of Raman pumps of the at least one Raman pump block an amount consistent with the determined amount.

Abstract: A method and apparatus for determining if an optical input signals has been interrupted and responsively replacing an interrupted optical input signal with a replacement optical signal having a similar optical profile (e.g., such as a loopback between OADMs within a backbone network), thereby insuring that transient-induced high speed optical amplifier adjustments are avoided.

Abstract: A method and apparatus for modifying the extinction ratio of a modulated optical signal by adapting a modulator driver signal in response to differences in spectral regions of the modulated optical signal. In another embodiment for modifying the extinction ratio of a modulated optical signal, a modulator signal is adapted in response to differences between a profile of the modulated optical signal and a desired profile.

Abstract: A technique for improving optical cross-connections comprises placing a switch in front of a number of processing units. So configured, the units are no longer dedicated to a specific link or signal. When necessary, a unit is connected/disconnected to one or more optical links by the switch to carry out any number of processing functions, such as regeneration, Raman pumping, dispersion equalization/compensation or performance monitoring. Because the units are no longer dedicated to specific links the cost of the cross-connections and the network it is a part of can be reduced.