Abstract: An optical communication system is operable to communicate a plurality of wavelength signals at a bit rate of at least 9.5 gigabits per second over a multiple span communication link spanning at least 400 kilometers without optical regenerators. The plurality of wavelength signals include a bandwidth of more than 32 nanometers separated into at least 160 optical channels. The system includes a plurality of optical transmitters implementing a forward error correction (FEC) coding technique. The FEC encoded wavelength signals comprise a bit error rate of 10?09 or better after FEC decoding. The system also includes at least five (5) optical add/drop multiplexers (OADMs), each coupled to one or more spans of the multiple span communication link. The system further includes a plurality of amplifiers each coupled to one or more spans of the communication link, at least a majority of the amplifiers comprise a distributed Raman amplification stage.

Abstract: An optical communication system is operable to communicate a plurality of wavelength signals at a bit rate of at least 9.5 gigabits per second over a multiple span communication link spanning at least 400 kilometers without optical regenerators. The plurality of wavelength signals include a bandwidth of more than 32 nanometers separated into at least 160 optical channels. The system includes a plurality of optical transmitters implementing a forward error correction (FEC) coding technique. The FEC encoded wavelength signals comprise a bit error rate of 10?09 or better after FEC decoding. The system also includes at least five (5) optical add/drop multiplexers (OADMs), each coupled to one or more spans of the multiple span communication link. The system further includes a plurality of amplifiers each coupled to one or more spans of the communication link, at least a majority of the amplifiers comprise a distributed Raman amplification stage.

Abstract: An optical communication system includes a plurality of optical add/drop multiplexers (OADMs). The plurality of OADMs includes at least five low distortion OADMs. Each OADM is coupled between spans of a multiple span communication link and operable to receive a multiple wavelength signal. The multiple wavelength signal includes a plurality of bands of wavelength signals each separated from other bands of wavelength signals by one or more guard-channels. In one embodiment, each of the at least five low distortion OADMs adds/drops a common first band of wavelengths to/from the multiple wavelength signal. In some embodiments, a spectral distortion associated with a pass-through wavelength signal spectrally adjacent to one of the one or more guard-channels is no more than three decibels after exiting the last of the plurality of low distortion OADMs. In those embodiments, the guard-channel is adjacent to the first band of wavelengths.

Abstract: An optical communication system is operable to communicate a plurality of wavelength signals at a bit rate of at least 9.5 gigabits per second over a multiple span communication link spanning at least 400 kilometers without optical regenerators. The plurality of wavelength signals include a bandwidth of more than 32 nanometers separated into at least 160 optical channels. The system includes a plurality of optical transmitters implementing a forward error correction (FEC) coding technique. The FEC encoded wavelength signals comprise a bit error rate of 10?09 or better after FEC decoding. The system also includes at least five (5) optical add/drop multiplexers (OADMs), each coupled to one or more spans of the multiple span communication link. The system further includes a plurality of amplifiers each coupled to one or more spans of the communication link, at least a majority of the amplifiers comprise a distributed Raman amplification stage.

Abstract: A method and system for transporting traffic having disparate qualities of service classes across a packet-switched network includes receiving at an ingress node of a network a plurality of packets each comprising a quality of service (QoS) class defined externally to the network. Packets having a QoS class comprising delay bound guarantees and a low drop priority are combined into a first internal QoS class. Packets having a QoS class comprising a flexible drop priority and no delay bound guarantees are combined into a second internal QoS class. Packets having a QoS class including no delivery guarantees are combined into a third internal QoS class. The packets are transmitted in the network based on their internal QoS class.

Abstract: An optical communication system includes a plurality of optical add/drop multiplexers (OADMs). The plurality of OADMs includes at least five low distortion OADMs. Each OADM is coupled between spans of a multiple span communication link and operable to receive a multiple wavelength signal. The multiple wavelength signal includes a plurality of bands of wavelength signals each separated from other bands of wavelength signals by one or more guard-channels. In one embodiment, each of the at least five low distortion OADMs adds/drops a common first band of wavelengths to/from the multiple wavelength signal. In some embodiments, a spectral distortion associated with a pass-through wavelength signal spectrally adjacent to one of the one or more guard-channels is no more than three decibels after exiting the last of the plurality of low distortion OADMs. In those embodiments, the guard-channel is adjacent to the first band of wavelengths.

Abstract: A Raman amplifier apparatus includes an optical transmission line with an input to receive an optical signal, an output that passes the optical signal, a first Raman gain fiber and a second Raman gain fiber. A first WDM is positioned between the second Raman gain fiber and the output. A first set of pump wavelengths is input to the first WDM. A second WDM is positioned between the first and second Raman gain fibers. A second set of pump wavelengths is input to the second WDM. At least a portion of the first set of pump wavelengths are different than the second set of pump wavelengths. The first and second set of pump wavelengths propagate in the same direction.

Abstract: In one aspect of the invention, an apparatus operable to convert wavelengths of a plurality of optical signals includes a coupler operable to receive a pump signal and a plurality of input signals each input signal comprising at least one wavelength different than the wavelengths of others of the plurality of input optical signals. The apparatus further includes an optical medium operable to receive the pump signal and the plurality of input signals from the couplet, wherein the pump signal and each of the plurality of input signals are synchronized to overlap at least partially during at least a part of the time spent traversing the optical medium to facilitate generation of a plurality of converted wavelength signals each comprising a wavelength that is different than the wavelengths of at least some of the plurality of input signals. Various embodiments can result in low cross-talk and/or low polarization sensitivity.

Abstract: A method and system for transporting traffic in a packet-switched network segments high priority pass-through traffic from low priority pass-through traffic. The high priority pass-through traffic is transmitted on an egress link preferentially over the low priority pass-through traffic and ingress high priority local traffic. The ingress high priority local traffic is transmitted on the egress link preferentially over the low priority pass-through traffic.

Abstract: A multi-stage Raman amplifier includes a first Raman amplifier stage having a first sloped gain profile operable to amplify a plurality of signal wavelengths, and a second Raman amplifier stage having a second sloped gain profile operable to amplify at least most of the plurality of signal wavelengths after those wavelengths have been amplified by the first stage. The second sloped gain profile is approximately complementary slope to the slope of the first sloped gain profile. The combined effect of the first and second Raman stages contributes to an approximately flat overall gain profile over the plurality of signal wavelengths.

Abstract: A Raman amplifier apparatus includes an optical transmission line with an input to receive an optical signal, an output that passes the optical signal, a first Raman gain fiber and a second Raman gain fiber. A first WDM is positioned between the second Raman gain fiber and the output. A first set of pump wavelengths is input to the first WDM. A second WDM is positioned between the first and second Raman gain fibers. A second set of pump wavelengths is input to the second WDM. At least a portion of the first set of pump wavelengths are different than the second set of pump wavelengths. The first and second set of pump wavelengths propagate in the same direction.

Abstract: An amplifier apparatus includes an optical transmission line with a Raman amplification region that provides a pump to signal power conversion efficiency of at least 20%. The Raman amplification region is configured to amplify a signal with multiple wavelengths over at least a 30 nm range of wavelengths. A pump source is coupled to the optical transmission line. An input optical signal is amplified in the Raman amplification region and an output signal is generated that has at least 100 mW more power than the input optical signal.

Abstract: One aspect of the invention includes an optical amplifier operable to amplify a plurality of optical wavelength signals at least in part through Raman amplification. The amplifier includes an input operable to receive a plurality of wavelength signals and an output operable to communicate an amplified version of at least some of the plurality of wavelength signals. The amplifier further includes a pump assembly operable to generate one or more pump signals and a gain medium operable to receive the plurality of wavelength signals and the one or more pump signals and to facilitate amplification of at least some of the plurality of wavelength signals. The amplifier has associated with it a noise figure having a shape varying as a function of wavelength. At least one of the one or more pump signals is operable to have its power varied to selectively control the shape of the noise figure.

Abstract: A Raman amplifier apparatus includes an optical transmission line with an input to receive an optical signal, an output that passes the optical signal, a first Raman gain fiber and a second Raman gain fiber. A first WDM is positioned between the second Raman gain fiber and the output. A first set of pump wavelengths is input to the first WDM. A second WDM is positioned between the first and second Raman gain fibers. A second set of pump wavelengths is input to the second WDM. At least a portion of the first set of pump wavelengths are different than the second set of pump wavelengths. The first and second set of pump wavelengths propagate in the same direction.

Abstract: A multi-stage Raman amplifier includes a first Raman amplifier stage having a first sloped gain profile operable to amplify a plurality of signal wavelengths, and a second Raman amplifier stage having a second sloped gain profile operable to amplify at least most of the plurality of signal wavelengths after those wavelengths have been amplified by the first stage. The second sloped gain profile is approximately complementary slope to the slope of the first sloped gain profile. The combined effect of the first and second Raman stages contributes to an approximately flat overall gain profile over the plurality of signal wavelengths.

Abstract: In one aspect of the invention, a method of amplifying optical signals includes identifying one of a plurality of pump signals driving an amplification system as a failing pump signal comprising a reduced power compared to a normal power of the failing pump signal. The method further includes adjusting the power of at least one other of the plurality of pump signals based at least in part on the failing pump signal to at least partially compensate for a degradation of performance of the amplification system that would otherwise be caused by the reduction in power of the failing pump signal.

Abstract: A multi-stage Raman amplifier includes a first Raman amplifier stage having a first sloped gain profile operable to amplify a plurality of signal wavelengths, and a second Raman amplifier stage having a second sloped gain profile operable to amplify at least most of the plurality of signal wavelengths after those wavelengths have been amplified by the first stage. The second sloped gain profile is approximately complementary slope to the slope of the first sloped gain profile. The combined effect of the first and second Raman stages contributes to an approximately flat overall gain profile over the plurality of signal wavelengths.

Abstract: A multi-stage Raman amplifier includes a first Raman amplifier stage having a first sloped gain profile operable to amplify a plurality of signal wavelengths, and a second Raman amplifier stage having a second sloped gain profile operable to amplify at least most of the plurality of signal wavelengths after those wavelengths have been amplified by the first stage. The second sloped gain profile is approximately complementary slope to the slope of the first sloped gain profile. The combined effect of the first and second Raman stages contributes to an approximately flat overall gain profile over the plurality of signal wavelengths.

Abstract: One aspect of the invention includes an optical amplifier operable to amplify a plurality of optical wavelength signals at least in part through Raman amplification. The amplifier includes an input operable to receive a plurality of wavelength signals and an output operable to communicate an amplified version of at least some of the plurality of wavelength signals. The amplifier further includes a pump assembly operable to generate one or more pump signals and a gain medium operable to receive the plurality of wavelength signals and the one or more pump signals and to facilitate amplification of at least some of the plurality of wavelength signals. The amplifier has associated with it a noise figure having a shape varying as a function of wavelength. At least one of the one or more pump signals is operable to have its power varied to selectively control the shape of the noise figure.

Abstract: A multi-stage Raman amplifier includes a first Raman amplifier stage having a first sloped gain profile operable to amplify a plurality of signal wavelengths, and a second Raman amplifier stage having a second sloped gain profile operable to amplify at least most of the plurality of signal wavelengths after those wavelengths have been amplified by the first stage. The second sloped gain profile is approximately complementary slope to the slope of the first sloped gain profile. The combined effect of the first and second Raman stages contributes to an approximately flat overall gain profile over the plurality of signal wavelengths.