Abstract: A system comprising an optical receiver for multi-wavelength-channel optical communication, an optical source of spontaneous emission light and a tunable optical filter connected to receive the light at an input. The tunable optical filter can have a filter spectrum with spectral passbands separated by spectral notches. The system also includes an optical fiber link connecting an output of the optical filter to the optical receiver for multi-wavelength-channel optical communication. The receiver can be configured to make a measurement indicative of an optical power level in at least one of the notches or to make measurements of optical power levels and at least one of the passbands and at least one of the notches in response to the optical source transmitting the filtered light to the optical fiber link.

Abstract: A system comprising an optical receiver for multi-wavelength-channel optical communication, an optical source of spontaneous emission light and a tunable optical filter connected to receive the light at an input. The tunable optical filter can have a filter spectrum with spectral passbands separated by spectral notches. The system also includes an optical fiber link connecting an output of the optical filter to the optical receiver for multi-wavelength-channel optical communication. The receiver can be configured to make a measurement indicative of an optical power level in at least one of the notches or to make measurements of optical power levels and at least one of the passbands and at least one of the notches in response to the optical source transmitting the filtered light to the optical fiber link.

Abstract: An optical transmitter configured to perform digital signal equalization directed at mitigating the detrimental effects of a frequency roll-off in the transmitter's optical I-Q modulator. In various embodiments, a frequency-dependent spectral-correction function used for the digital signal equalization can be constructed to cause the spectrum of the modulated optical signal generated by the transmitter to have a desired degree of flatness in the vicinity of an optical carrier frequency and/or to at least partially mirror the frequency roll-off in the optical I-Q modulator.

Abstract: An optical transport system configured to transmit a set of two or more optical variants per bit-word, with the optical variants in the set being different from one another in one or more of the time of transmission, spatial localization, polarization of light, carrier wavelength, and subcarrier frequency. Differences between the optical variants may also be due to different respective constellation mapping. The optical variants of each set are detected and processed at the receiver in a manner that enables coherent summation of the corresponding electrical signals prior to constellation de-mapping. The coherent summation tends to average out the deleterious effects of linear and nonlinear noise/distortions imparted on the individual optical variants in the optical transport link because said noise/distortions are incoherent in nature. A BER reduction enabled by the use of optical variants may be implemented in addition to or instead of that provided by FEC coding.

Abstract: An optical transmitter configured to perform digital signal equalization directed at mitigating the detrimental effects of a frequency roll-off in the transmitter's optical I-Q modulator. In various embodiments, a frequency-dependent spectral-correction function used for the digital signal equalization can be constructed to cause the spectrum of the modulated optical signal generated by the transmitter to have a desired degree of flatness in the vicinity of an optical carrier frequency and/or to at least partially mirror the frequency roll-off in the optical I-Q modulator.

Abstract: An optical transport system configured to transmit a set of two or more optical variants per bit-word, with the optical variants in the set being different from one another in one or more of the time of transmission, spatial localization, polarization of light, carrier wavelength, and subcarrier frequency. Differences between the optical variants may also be due to different respective constellation mapping. The optical variants of each set are detected and processed at the receiver in a manner that enables coherent summation of the corresponding electrical signals prior to constellation de-mapping. The coherent summation tends to average out the deleterious effects of linear and nonlinear noise/distortions imparted on the individual optical variants in the optical transport link because said noise/distortions are incoherent in nature. A BER reduction enabled by the use of optical variants may be implemented in addition to or instead of that provided by FEC coding.

Abstract: A multi-pump phase modulator apparatus and operating method uses only one phase modulator to eliminate SBS without degrading idler(s). The single phase modulator phase modulates multiple pump signals to form multiple phase modulated pump signals using a modulation signal having a modulation period. A delay apparatus delays a first wavelength group by the modulation period relative to other wavelength groups. A combiner combines the delayed first wavelength group with the other wavelength groups to form a combined modulated multiple pump signal. In one embodiment a multi-pump phase parametric apparatus comprises the multi-pump phase modulator apparatus combined with a parametric apparatus to generate an amplified input signal and one or more idlers. Other embodiments of the multi-pump phase conjugator apparatus are used as part of an Optical Switch, Sampler, Tributary Extractor, and Regenerator.

Abstract: A terrestrial optical communication system including a plurality of optical nodes interconnected by optical links utilizes a hybrid optical/electrical cable to provide electrical power from one or more powered system nodes to one or more remote un-powered nodes that have no access to locally provided electrical power.

Abstract: A method of multiple-band switching using a multi-pump fiber parametric switch is demonstrated. The switching architecture combines parametric band amplification, wavelength conversion and selective signal conjugation, enabled by temporal control of at least one pump of the multi-pump parametric device. The switching speed of the present invention is limited by the rise time of the controlled pump(s).

Abstract: A multi-channel optical equalizer for intersymbol interference mitigation compensates for single- or multi-wavelength channels simultaneously and requires few adjustable parameters. The optical equalizer also compensates for overshoots and signal transition degradations in semiconductor optical amplifiers. The equalizer unit uses one control signal for magnitude and one to control signal phase. The equalizer includes a controllable coupling ratio coupler for splitting the light into two portions and a controllable interferometer having two arms, one arm having an additional delay which is equal to an integer multiple of 1/?f, where ?f is the channel spacing between adjacent wavelengths utilized in the optical system. The controllable interferometer has a controllable delay in a first or second arm for adjusting the relative phase of the light passing therethrough. A coupler combines the two signal portions from the first and second arms to form the equalized output signal.