Abstract: A method and system for distributed fault sensing and recovery in a communication system. A master controller is provided in each cable station of the system. Each master controller receives local alarms, e.g. aggregated alarms from associated shelf controllers, and may receive remote alarms from other master controllers. Local and remote alarms are compared to a profile provisioned in the master controllers for determining whether to perform a fault recovery function.

Abstract: A method and system for distributed fault sensing and recovery in a communication system. A master controller is provided in each cable station of the system. Each master controller receives local alarms, e.g. aggregated alarms from associated shelf controllers, and may receive remote alarms from other master controllers. Local and remote alarms are compared to a profile provisioned in the master controllers for determining whether to perform a fault recovery function.

Abstract: A system and method for loading unutilized channels of a WDM system with noise to improve system performance. A transmitter amplifier may impart noise to unutilized channels by reducing amplifier input or providing feedback of the amplifier output. Noise signals may also be looped back to the transmitter from received signals.

Abstract: An apparatus and method directed to testing and optimizing performance of an optical transmission system is disclosed, including at least one broadband dispersion compensation unit (DCU) or at least one depolarization device. The depolarization device may be used alone or in combination with the at least one broadband DCU. A method for optimizing performance of data channels in initial loading (IL) and full loading (FL) configurations of the optical transmission system is also disclosed.

Abstract: A system and method for loading unutilized channels of a WDM system with noise to improve system performance. A transmitter amplifier may impart noise to unutilized channels by reducing amplifier input or providing feedback of the amplifier output. Noise signals may also be looped back to the transmitter from received signals.

Abstract: An apparatus and method directed to testing and optimizing performance of an optical transmission system is disclosed, including at least one broadband dispersion compensation unit (DCU) or at least one depolarization device. The depolarization device may be used alone or in combination with the at least one broadband DCU. A method for optimizing performance of data channels in initial loading (IL) and full loading (FL) configurations of the optical transmission system is also disclosed.

Abstract: A system and method for loading unutilized channels of a WDM system with noise to improve system performance. A transmitter amplifier may impart noise to unutilized channels by reducing amplifier input or providing feedback of the amplifier output. Noise signals may also be looped back to the transmitter from received signals.

Abstract: An apparatus and method directed to testing and optimizing performance of an optical transmission system is disclosed, including at least one broadband dispersion compensation unit (DCU) or at least one depolarization device. The depolarization device may be used alone or in combination with the at least one broadband DCU. A method for optimizing performance of data channels in initial loading (IL) and full loading (FL) configurations of the optical transmission system is also disclosed.

Abstract: A protection switching architecture is used in a telecommunications system such as a wavelength division multiplexed (WDM) telecommunications system to replace a failed transmission line or a failed wavelength processing device. A spare wavelength processing device transmitter replaces a failed service wavelength processing device transmitter. A spare transmission line replaces a failed service transmission line. A spare wavelength processing device receiver monitors the optical signals, one wavelength at a time, on either the spare transmission line or the service transmission line and replaces one of the service wavelength processing device receivers. Wavelength selection equipment routes either the service transmission line or the service transmission line to the service wavelength processing device receivers and selects wavelengths to be monitored by the spare wavelength processing device receiver.

Abstract: A method and apparatus for performing error correction is described. A stream of data is encoded using concatenated error correcting codes. The encoded data is communicated over a transmission system. The encoded data is decoded using the codes and three levels of decoding.

Abstract: A wavelength division multiplex optical system includes a WDM combiner to provide a source signal, at least one transmitter coupled to an input of the WDM combiner, a broadband noise source, and a filter coupled between the broadband noise source and another input of the WDM combiner. In one embodiment, the filter is an optical notch filter. In an alternative embodiment, the filter includes a WDM demultiplexer coupled through plural filters to provide a plurality of noise signals and a WDM multiplexer coupled through at least one filter of the plural filters to respective noise signals.

Abstract: A wavelength division multiplex optical system includes a WDM combiner to provide a source signal, at least one transmitter coupled to an input of the WDM combiner, a broadband noise source, and a filter coupled between the broadband noise source and another input of the WDM combiner. In one embodiment, the filter is an optical notch filter. In an alternative embodiment, the filter includes a WDM demultiplexer coupled through plural filters to provide a plurality of noise signals and a WDM multiplexer coupled through at least one filter of the plural filters to respective noise signals.

Abstract: An apparatus for communicating data through information channels each being associated with its own wavelength comprises modulators and an optical multiplexer. Each modulator is associated with its own wavelength. The optical multiplexer is operationally coupled to the modulators. The optical multiplexer receives multiple input optical signals each of which is received from its own modulator. Each input optical signal has its own dispersion substantially equal to a dispersion of each remaining input optical signals.

Abstract: A WDM optical communication system is provided that includes a transmitter and a receiver. An optical fiber transmission path couples the transmitter to the receiver. The transmission path includes at least one repeater having an optical amplifier located therein. A dispersion compensator is disposed at an intermediate point along the transmission path. The intermediate point is located outside of the repeater. The compensator includes a wavelength routing device for dividing a signal having a prescribed bandwidth into a plurality of distinct sub-bands. A plurality of output paths is provided for respectively receiving the plurality of distinct sub-bands. The dispersion compensator also includes a dispersion compensating optical element coupled to each of the output paths. Each dispersion compensating optical element substantially compensates for dispersion at a prescribed wavelength within the bandpass of its respective sub-band.

Abstract: A Raman amplifier is provided that includes at least a portion of optical fiber in which an optical signal travels. The optical fiber portion may encompass all or part of the optical transmission path of an optical communication system. A pump energy unit is provided that includes first and second pump sources providing pump power at first and second wavelengths, respectively. The first and second wavelengths generate first and second gain profiles in the optical fiber portion. The first and second gain profiles overlap in wavelength. An optical coupler couples the pump power to the optical fiber portion. Since the gain profiles overlap, the Raman amplifier has a greater bandwidth than can be achieved with a pump operating at a single wavelength.

Abstract: A high-powered optical pump includes at least two sub-pumps. Each sub-pump generates light at different wavelengths. The outputs of the sub-pumps are coupled to a remote pump fiber. The resulting light transmitted on the remote pump fiber results in a lower Raman gain and Raman noise spectral peak than that generated by existing single wavelength high-powered optical pumps at the same power level. Therefore, increased power can be transmitted on the remote pump fiber in contrast to a single wavelength pump. Additionally, the total gain spectrum available for the amplification of signals is increased.

Abstract: A method is provided for transmitting an optical signal in an optical communication system. The system includes a transmitter for generating the optical signal, a receiver for detecting the signal, and an optical fiber communication link interposed between the transmitter and receiver. The optical fiber communication link includes transmission optical fibers concatenated with a plurality of Raman amplifiers and at least one rare earth doped optical fiber amplifier. The method includes the steps of: amplifying the optical signal as it advances through each of the plurality of Raman amplifiers; and compensating for variations in transmission path losses to restore the optical signal to a nominal power level as it advances through the rare earth doped optical fiber amplifier by maintaining the doped optical fiber amplifier in its saturated state.

Abstract: Currently laser diode pump redundancy for an optical fiber amplifier is obtained by selectively connecting one of two diode pumps to an optical amplifier via an optical switch. When the diode laser pump which is connected to the amplifier becomes defective, the optical switch is activated, either remotely or automatically, and the good laser diode is substituted for the defective laser diode pump. In another arrangement, two laser diodes are coupled to an optical fiber amplifier via a polarization-dependent optical coupler. In each instance, a second laser diode is required to provide pump redundancy for an optical fiber amplifier.In this invention, at least, two laser diodes are coupled via a 3 dB optical coupler to supply pump power to each of the two optical fiber amplifiers simultaneously. If one of the laser diode pumps fails, the other laser diode pump provides pump power to each of the optical fiber amplifiers.