Abstract: An optical communication system is disclosed. The optical communication system may include a first fiber pump laser system having a first single mode (SM) fiber output configured to output a first pump laser radiation, a second fiber pump laser system having a second SM fiber output configured to output a second pump laser radiation, at least one combiner-splitter element configured to combine the first pump laser radiation and the second pump laser radiation and to transmit N portions of pump laser radiation, and N doped fiber amplifiers, where N is at least four, each doped fiber amplifier configured to receive one portion of the N portions of pump laser radiation and an input optical signal to be amplified, amplify the input optical signal into an amplified optical signal, and to transmit the amplified optical signal.

Abstract: A method and apparatus is provided for obtaining status information from a given location along an optical transmission path. The method begins by generating a cw probe signal having a prescribed frequency that is swept over a prescribed frequency range. The cw probe signal is transmitted over the optical path and a returned COTDR signal in which status information concerning the optical path is embodied is received over the optical path. A receiving frequency within the prescribed frequency range of the returned COTDR signal is detected to obtain the status information. The detecting step includes the step of sweeping the receiving frequency at a rate equal to that of the prescribed frequency. A period associated with the receiving frequency is temporally offset from a period associated with the prescribed frequency.

Abstract: An optical communication system transmitting a plurality of channel wavelengths is provided. The system includes a transmitter unit, a receiver unit, and an optical transmission path interconnecting the transmitter and receiver units. The transmission path has a concatonation of optical fibers defining a dispersion map such that each of the channel wavelengths are located at FMX and XPM antiresonances at which FWM and XPM are suppressed.

Abstract: An undersea optical repeater is provided. The repeater includes a pressure vessel for use in an undersea environment. The pressure vessel includes a pressure housing and at least two cable reeving elements disposed on opposing ends of the pressure housing for respectively receiving ends of optical cables that each include an electrical conductor therein. The cable receiving elements are adapted to be in electrical contact with the respective electrical conductors in the optical cables. At least one optical amplifier is located in the pressure vessel. The optical amplifier includes at least one electrical component adapted to receive electrical power from the electrical conductors in the optical cables. The pressure housing includes a dielectric layer having sufficient dielectric properties for electrically isolating the cable receiving elements from one another to provide a voltage thereacross.

Abstract: A method is provided for using optical time-domain reflectometry (OTDR) with a bi-directional optical transmission system that includes a plurality of terminals interconnected by first and second unidirectional optical transmission paths having at least one repeater therein. The method begins by transmitting a probe signal from a first terminal through the repeater over the first optical transmission path. A returned OTDR signal is received over the first optical transmission path in which status information concerning the first optical transmission path is embodied. The returned OTDR signal is transformed to a digitized electrical signal and the digitized electrical signal is transformed to an optical data signal. Finally, the optical data signal is transmitted over the second optical transmission path to the first terminal for extracting the status information embodied therein.

Abstract: An optical and electrical isolating unit for use with a branching unit located in an undersea optical transmission system is provided. The unit includes a pressure vessel adapted for use in an undersea environment. First, second and third ports are located in the pressure vessel for receiving first, second and third undersea transmission cables, respectively. The first cable includes an electrical power conductor and at least one optical fiber. The second cable includes an electrical conductor, and the third cable, which is electrically unpowered, includes at least one optical fiber. An electrical power conductor segment is provided for electrically coupling the conductor in the first cable received in the first port to the conductor in the second cable received in the second port. At least one optical fiber segment is located in the pressure vessel, which segment optically couples the optical fiber of the first cable to the optical fiber of the third cable.

Abstract: A branching unit is provided for interconnecting at least three undersea optical transmission cables. The branching unit includes first, second and third ports for receiving first, second and third undersea optical transmission cables, respectively. The first and second cables each include an electrical power conductor and a plurality of first optical fibers. The third cable is electrically unpowered and includes at least one drop optical fiber and at least one add optical fiber. An electrical power conductor segment is provided for electrically coupling the conductor in the first cable received in the first port to the conductor in the second cable received in the second port. A first optical fiber segment optically couples a first of the plurality of first optical fibers in one of the first or second cables to the drop optical fiber of the third cable.

Abstract: A method and apparatus is provided for using optical time-domain reflectometry (OTDR) with a WDM transmission system that includes a plurality of terminals interconnected by at least two pairs of unidirectional optical transmission paths each of which has at least one repeater therein. The method begins by transmitting an optical probe signal from a first OTDR unit associated with a first terminal into the repeater over a first optical path in a first of the at least two pairs of unidirectional optical transmission paths. The first OTDR unit receives a first returned OTDR signal over a second optical path in the first optical path pair. The first OTDR signal contains status information concerning the first optical path in the first optical path pair. The optical probe signal from the first optical path in the first optical path pair is coupled to a second optical path in the second optical path pair.

Abstract: An apparatus is provided for transmitting an optical signal. The apparatus includes an optical signal source for generating an optical signal having a plurality of optical channels onto which data is modulated at a plurality of predetermined frequencies to provide a plurality of optical data channels. An amplitude modulator is coupled to the optical signal source for modulating each of the optical channels with a waveform that is independently adjustable from one another. A clock, coupled to the amplitude modulator, has a plurality of frequencies that respectively determine the modulation frequencies imparted to the plurality of optical channels by the amplitude modulator. Each of the frequencies of the clock is phase locked and equal to its respective predetermined frequency at which is data is modulated.

Abstract: The single-wavelength bit-rate capacity of an ultra long distance soliton transmission system is increased by using a combination of polarization and time-division multiplexing. More specifically, two streams of differently (preferably orthogonally) polarized solitons are interleaved (time division multiplexed) at a transmitter, and later separated at the receiver to recover both data streams. The system operates at speeds of up to 7.5 GHZ and provides very thorough separation of channels required for 10.sup.-12 error rates at distances of 9000 km.