Abstract: An optical communication system includes a transmission fiber that is operable to receive at least one optical signal and at least one pump signal. The optical signal includes one or more optical signal wavelengths and a power level at approximately a minimum threshold power level. The pump signal co-propagates with at least a portion of the optical signal over at least a portion of the transmission fiber. In one particular embodiment, the pump signal operates to amplify the optical signal to approximately a maximum threshold power level as the pump signal and the optical signal traverse the portion of the transmission fiber.

Abstract: Methods and systems for improved visual presentation and organization of network performance data are provided. According to one embodiment, a method is provided for displaying performance data. Information is received regarding a selected path of multiple paths associated with network elements that are part of a service provider network (e.g., a DWDM network). A map of the selected path is displayed responsive to receipt of the information regarding the selected path. The map of the selected path includes (i) graphical representations of participating network elements of the network elements that are associated with the selected path and (ii) graphical representations of client ports, line ports and port connections associated with the participating network elements. Along with the map, information regarding performance data associated with the participating network elements is also displayed.

Abstract: An optical transmission system comprises two optical fibers carrying optical signal traffic between two terminals, and a plurality of optical repeaters coupled to the two fibers each repeater having a permanently connected passive high loss loop back circuit between the two fibers. One terminal includes a transmitter, which launches a pulsed supervisory signal on a dedicated supervisory wavelength into one optical fiber, and a receiver, which detects a portion of the supervisory signal looped back from each repeater in order to identify the existence and location of faults in the transmission system. The pulsed supervisory signal is of sufficiently short duration such that portions of the signal returned from each repeater do not overlap with one another and interference with the counter-propagating traffic is avoided by utilizing a dedicated supervisory wavelength. Each return pulse is integrated sequentially by a single detector and processed by heterodyne reception and synchronous demodulation.

Abstract: Embodiments described herein relate to an optical fiber stretch that may experience forward Raman amplification in which the peak optical signal power occurs at some distance from the transmitter. Smaller effective area optical fiber is used at a portion of the optical fiber stretch in which the optical signal power is increasing, while larger effective area optical fiber is used at a more remote stretch of the optical fiber stretch that experiences the peak optical signal power. Thus, the quality of the signal is better preserved since the larger effective area fiber reduces maximum optical signal density thereby reducing non-linear degradations on signal quality.

Abstract: A method of communicating an optical signal includes generating an optical signal at a bit rate of at least 2.5 Gb/s. The optical signal including at least thirty optical channels. In one particular embodiment, at least some of the thirty optical channels reside within a 1567-1620 nanometer wavelength range. The method also includes receiving the optical signal at a ROPA that includes a rare-earth doped optical fiber. In addition, the method includes introducing a pump signal to a communication span of the unrepeatered optical communication system. The pump signal operable to amplify the optical signal by Raman amplification within the communication span and including at least one pump signal wavelength operable to excite the rare-earth doped fiber. The method further includes receiving the optical signal after the optical signal has traversed at least 200 kilometers of the communication span.

Abstract: A system and method are provided for controlling the pre-emphasis applied to an optical signal, in which the output level of individual transmitters is controlled in order to reach a pre-defined desired value of a quality metric. Transmitters are able to adjust their output power without external control in such a way as to optimise the power distribution across the system.

Abstract: There is provided a method and apparatus for tuning an optical discriminator to the carrier frequency of an optical signal to allow superior reception of said signal. The carrier frequency of the signal is dithered during a test phase in order to provide information that allows a subsequent tuning phase to optimise the reception of the optical signal, as measured by a signal quality metric. The tuning phase may comprise adjustment of one or both of the carrier frequency and the optical discriminator.

Abstract: An optical communication system includes a gain medium that is capable of receiving at least one optical signal that includes one or more optical signal wavelengths. The system also includes one or more pump sources that are capable of generating at least one pump signal for introduction to the gain medium. The pump signal includes one or more fractional Raman order pump wavelengths having a Raman gain peak that is a non-integer multiple of one stokes shift from each of the one or more optical signal wavelengths. In one particular embodiment, the pump signal interacts with the optical signal as the pump signal traverses at least a portion of the gain medium.

Abstract: Optical amplification by combining two or more optical signals from separate optical fibers, amplifying the combined signal using an optical fiber, and separating the amplified signals into their constituent optical signals. The separated optical signals may then be sent further in the direction they had been heading before combination. This allows multiple optical signals to be amplified using a single optical amplifier, perhaps even in a single optical fiber. Although not required, the two optical signals may even be travelling in different directions.

Abstract: The alteration of the bandwidth of an optical amplifier. Before alteration, optical signals having a first set of wavelengths are provided through a gain medium of the optical amplifier. In addition, a first pump having a set of pump wavelengths is propagated through the gain medium to thereby amplify the optical signals. After alteration, optical signals having at least a partially different set of wavelengths are able to be optically amplified by coupling a second pump into the optical medium. The second pump is at least partially distinct from the first pump in that the second pump includes at least one pump wavelength that was not included in the first pump.

Abstract: An optical amplification mechanism that introduces optical pump(s) into one port of an optical circulator. The optical circulator directs the optical pumps from that port into another port that is coupled to the output of a gain stage. The optical pump(s) then pass from the output to the input of the gain stage while amplifying an optical signal passing from the input to the output of the gain stage. A residual amount of optical pump(s) that exits the input of the gain stage is reflected back into the input of the gain stage. The reflected optical pump(s) then further assists in the amplification of the optical signal. Other embodiments are also disclosed.

Abstract: Fiber optic transmission technologies that allow DPSK or even higher order PSK to be performed at 20 gigabits per second per channel or even higher bit rates in a WDM (e.g., DWDM) wavelength multiplexed channeling environment. The technology employs pre-compensation of chromatic error dispersion such for each of most, if not all, channels have a portion of minimum absolute accumulated dispersion that occurs somewhere within the length (perhaps at the mid-point) of the optical channel. Post-compensation is then employed at the receiver to reduce or even potentially eliminate the chromatic dispersion. The technology allows for reduced bit error rates at high bit rates over even very long haul (e.g., trans-oceanic submarine or long terrestrial) optical fiber links, and for all channels.

Abstract: An apparatus for amplifying optical communications systems is provided in which one or more amplifier modules, each containing an optical amplifier and at least two pump lasers, are optically isolated from a plurality of control modules. Each control module controls a single pump laser in one or more of the amplifier modules. A control module can thus be removed without disabling any amplifier module, while the plurality of pump lasers in each amplifier module allow for effective operation even if one of the pump lasers should fail. The pump lasers in each module are controlled by a master-slave relationship, whereby the master pump laser is adjusted to optimise overall output, while the slave laser(s) are adjusted to equalize the power output of the lasers.

Abstract: There are provided surge protection devices for undersea optical repeaters. An optical repeater drive circuit incorporating a diode chain design includes a diode array formed of a plurality of banks of two or more parallel forward-biased diodes, each diode in a given bank being in electrical contact with all the diodes in adjacent banks; and, optical repeater control circuitry connected in parallel with the diode array. A component for providing surge protection to an optical repeater incorporates a substrate formed of an insulating material and a first substantially planar conducting coil embedded within the substrate.

Abstract: A method of communicating an optical signal includes generating an optical signal at a bit rate of at least 2.5 Gb/s. The optical signal including at least thirty optical channels. In one particular embodiment, at least some of the thirty optical channels reside within a 1567-1620 nanometer wavelength range. The method also includes receiving the optical signal at a ROPA that includes a rare-earth doped optical fiber. In addition, the method includes introducing a pump signal to a communication span of the unrepeatered optical communication system. The pump signal operable to amplify the optical signal by Raman amplification within the communication span and including at least one pump signal wavelength operable to excite the rare-earth doped fiber. The method further includes receiving the optical signal after the optical signal has traversed at least 200 kilometers of the communication span.

Abstract: An optical communications system comprising: an optical input and an output, a source of input signals in an asymmetric format and having a duty cycle, a modulator for modulating the input signals, to produce an asymmetric signal, the modulator comprising a Mach-Zehnder interferometer; drive means for driving the modulator at a predetermined modulator drive voltage; bias means for applying a bias voltage to the modulator; adjustment means for adjusting a first variable chosen from one of the bias voltage, gain voltage, or duty cycle in response to the relationship existing between changes in the amplitude of the asymmetric signal and changes in the first variable, characterized in that the system further comprising varying means for varying a second variable, different to the first variable and chosen from one of the bias voltage, gain voltage or duty cycle in response to adjustments made to the first variable; and a monitor for recording the average optical output power.

Abstract: A method of communicating an optical signal includes generating an optical signal at a bit rate of at least 2.5 Gb/s. The optical signal including at least thirty optical channels. In one particular embodiment, at least some of the thirty optical channels reside within a 1567-1620 nanometer wavelength range. The method also includes receiving the optical signal at a ROPA that includes a rare-earth doped optical fiber. In addition, the method includes introducing a pump signal to a communication span of the unrepeatered optical communication system. The pump signal operable to amplify the optical signal by Raman amplification within the communication span and including at least one pump signal wavelength operable to excite the rare-earth doped fiber. The method further includes receiving the optical signal after the optical signal has traversed at least 200 kilometers of the communication span.

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 includes a first end terminal comprising a first transponder operable to receive a first electrical signal and generate an optical signal based at least in part on the first electrical signal for communication to a multiple span communication link. The optical signal experiences at least partial dispersion compensation from an optical dispersion compensating element as it traverses the communication link. The system also includes a second end terminal comprising a second transponder operable to receive the optical signal and generate a second electrical signal based at least in part on the optical signal. At least one of the first and second end terminals further includes an electronic dispersion compensation module operable to provide electronic dispersion compensation to at least a portion of at least one of the first and second electrical signals.