Abstract: A collapsed ring fiber optic system includes a service path and a protection path provides at a shallow water portion of the fiber optic system, to deal with any fiber cuts that may occur at the shallow water portion without loss of main trunk bandwidth. The service and protection paths meet at a branch point, which is preferably located at a deep water portion of the fiber optic system. A passive combiner or a 1×2 switch is provided at the branch unit, along with a detector and a processor, to determine whether any signals are being received from the service path, and if not, to reconfigure the system to accept signals from the protection path. At another shallow water portion of the fiber optic system, nearby where a destination is located, the signal provided on the optical path over the deep water portion is split into a service path and a protection path, to provide redundancy to deal with any fiber cuts that may occur.

Abstract: Methods, apparatuses and systems facilitating the aggregation or bonding of physical communications links into higher-bandwidth logical links. A novel link bonding and encapsulation protocol scheme that optimizes the efficiency of data transfer across the physical links, while still allowing for desired Quality of Service (QoS) levels to high-priority traffic, such as voice data, with low delay requirements. Data streams are divided and concurrently transported over multiple physical links that are aggregated or bonded together to form one logical link. At the receive end, the original cell streams are recovered from the bonded logical links. In one embodiment, the physical links are xDSL links transmitting and receiving signals via conventional copper twisted-pair cabling.

Abstract: An optical transmission system includes a number of corresponding modular multiplexing and demultiplexing units used in transmitting and receiving an optical signal respectively. Additionally, compensation components compensate for optical dispersion experienced by the optical signal. The modular multiplexing and demultiplexing units are assembled in a cascade fashion at the transmit side and the receive side of the optical transmission system, respectively. The dispersion compensation components share dispersion compensation fiber across the cascaded units.

Abstract: A system and method of providing a transmission span for a telecommunications link based on a remote Er3+-doped fiber amplification scheme is provided, where a transmission span comprises first through third segments each respectively comprising first-third optical fibers having first-third fiber lengths and first-third physical properties. The first and third segments are optically coupled to opposing ends of the second segment. At least one of the first and third physical properties is different from the second physical property, where the first segment provides low nonlinearity, the third segment provides distributed gain, and the second segment compensates for the dispersion of the first and third segments. The span also includes a fourth optical fiber that is doped with a non-zero concentration of Er3+, and is disposed at a location in the span for remote pumping to provide discrete amplification of the optical signal.

Abstract: An optical communications system, including first terminal equipment, second terminal equipment, third terminal equipment, a first powered optical segment connected to the first terminal equipment and including at least one amplifier, a second powered optical segment connected to the second terminal equipment and including at least one amplifier, an unpowered optical segment connected to the third terminal equipment, and a branch unit connecting the first powered segment, the second powered segment, and the unpowered segment via passive, all-optical connections, and wherein the unpowered segment is pumped with optical energy through the branch unit from at least one of the amplifiers in the first and second powered segments.

Abstract: A system and method of providing a transmission span for a telecommunications link based on a remote Er3+-doped fiber amplification scheme is provided, where a transmission span comprises first through third segments each respectively comprising first-third optical fibers having first-third fiber lengths and first-third physical properties. The first and third segments are optically coupled to opposing ends of the second segment. At least one of the first and third physical properties is different from the second physical property, where the first segment provides low nonlinearity, the third segment provides distributed gain, and the second segment compensates for the dispersion of the first and third segments. The span also includes a fourth optical fiber that is doped with a non-zero concentration of Er3+, and is disposed at a location in the span for remote pumping to provide discrete amplification of the optical signal.

Abstract: Methods, apparatuses and systems facilitating the aggregation or bonding of physical communications links into higher-bandwidth logical links. The present invention features a novel link bonding and encapsulation protocol scheme that, in one embodiment, optimizes the efficiency of data transfer across the physical links, while still allowing for desired Quality of Service (QoS) levels to high-priority traffic, such as voice data, with low delay requirements. Embodiments of the present invention allow a variety of service types to be transported transparently over bonded physical links. According to one embodiment, data streams are divided and concurrently transported over multiple physical links that are aggregated or bonded together to form one logical link. At the receive end, the original cell streams are recovered from the bonded logical links. In one embodiment, the physical links are xDSL links transmitting and receiving signals via conventional copper twisted-pair cabling.

Abstract: An optical transmission system includes a number of corresponding modular multiplexing and demultiplexing units used in transmitting and receiving an optical signal respectively. Additionally, compensation components compensate for optical dispersion experienced by the optical signal. The modular multiplexing and demultiplexing units are assembled in a cascade fashion at the transmit side and the receive side of the optical transmission system, respectively. The dispersion compensation components share dispersion compensation fiber across the cascaded units.

Abstract: An optical communications system, including first terminal equipment, second terminal equipment, third terminal equipment, a first powered optical segment connected to the first terminal equipment and including at least one amplifier, a second powered optical segment connected to the second terminal equipment and including at least one amplifier, an unpowered optical segment connected to the third terminal equipment, and a branch unit connecting the first powered segment, the second powered segment, and the unpowered segment via passive, all-optical connections, and wherein the unpowered segment is pumped with optical energy through the branch unit from at least one of the amplifiers in the first and second powered segments.

Abstract: A method of increasing capacity on a long-haul undersea cable system having at least one optical fiber, said method comprising interleaving counter-propagating forward-propagating and backward-propagating signals in forward and backward channels on a common optical fiber, wherein the wavelength offset between said forward and backward channels is typically half of the channel spacing of co-propagating signals.

Abstract: A system and method of providing a transmission span that compensates for signal attenuation, dispersion, and nonlinearity of an optical signal communicated between two line units of a transmission link includes dividing the transmission span into a plurality of fiber segments and selecting a particular fiber for each of the segments. The fiber selection and arrangement of fibers within the span can be selected in accordance with the nonlinearity, dispersion conditions, and distributed gain conditions of the constituent fibers. In a three segment map, the first segment can provide low non linearity, the third segment can provide distributed gain, and the second segment can compensate for the dispersion of the first and third segments. The span can be used, e.g., for distributed Raman amplification. The span can alternatively include a two segment map, a four segment map, or a map with additional segments.

Abstract: A collapsed ring fiber optic system includes a service path and a protection path provides at a shallow water portion of the fiber optic system, to deal with any fiber cuts that may occur at the shallow water portion without loss of main trunk bandwidth. The service and protection paths meet at a branch point, which is preferably located at a deep water portion of the fiber optic system. A passive combiner or a 1×2 switch is provided at the branch unit, along with a detector and a processor, to determine whether any signals are being received from the service path, and if not, to reconfigure the system to accept signals from the protection path. At another shallow water portion of the fiber optic system, nearby where a destination is located, the signal provided on the optical path over the deep water portion is split into a service path and a protection path, to provide redundancy to deal with any fiber cuts that may occur.

Abstract: A hybrid Raman-EDFA provides gain equalization over the C-band and L-band. The hybrid Raman-EDFA includes a Raman section producing a Raman gain and an EDFA section producing an EDFA gain complimenting the Raman gain. The EDFA section preferably includes a highly inverted, single-stage EDFA to produce the complimenting EDFA gain shape. One embodiment of the EDFA section includes a high return loss termination located after the erbium fiber to receive unabsorbed pump power. Multiple hybrid Raman-EDFAs can be connected in an amplifier chain in a transmission system. The transmission system preferably provides a dispersion map including regular composite fiber spans followed by at least one compensating span of negative dispersion fibers. The Raman sections of the hybrid Raman-EDFAs are preferably coupled to negative dispersion fiber in the transmission system.

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

Abstract: An apparatus comprises operationally coupled optical fiber segments that define an optical sublink. The optical sublink has link spans including a first link span and a second link span. The first link span has an average dispersion with a magnitude greater than zero. The second link span has an average dispersion with a magnitude greater than zero. The optical sublink has an end-to-end dispersion less than an end-to-end dispersion tolerance limit.

Abstract: A method of providing power via a power cable to optical line units for amplification of an optical signal propagating along an optical fiber having a first end and a second end and terminated solely at the first end and the second end is provided comprising terminating the power cable at a location between a first plurality of line units and a second plurality of line units.

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 collapsed ring fiber optic system includes a service path and a protection path provides at a shallow water portion of the fiber optic system, to deal with any fiber cuts that may occur at the shallow water portion without loss of main trunk bandwidth. The service and protection paths meet at a branch point, which is preferably located at a deep water portion of the fiber optic system. A passive combiner or a 1×2 switch is provided at the branch unit, along with a detector and a processor, to determine whether any signals are being received from the service path, and if not, to reconfigure the system to accept signals from the protection path. At another shallow water portion of the fiber optic system, nearby where a destination is located, the signal provided on the optical path over the deep water portion is split into a service path and a protection path, to provide redundancy to deal with any fiber cuts that may occur.

Abstract: High power repeaters for use in amplifying optical data signals transmitted through undersea fiber optic cables are disclosed. Raman amplification schemes using 100 or more pump lasers are integrated into industry standard sized pressure vessels for amplifying optical data signals transmitted through one or more fiber optic pairs. Other repeater features include high density packaging, efficient power distribution, and component sharing.

Abstract: An IP router is integrated with an LRTR. A forward error correction (FEC) unit associated with the LRTR provides a frame structure, error detection and other functionality previously performed by SDH or SONET protocol devices. The FEC unit is clocked independently of the routing functionality and a processor coordinates the flow of IP data packets between the routing functionality and the LRTR functionality, e.g., by controlling buffer underflow and overflow conditions.