Abstract: A pluggable aggregation module adapted to be plugged into a network device of an optical network, said pluggable aggregation module comprising optical frontends configured to connect said pluggable aggregation module with a corresponding number of modules to exchange optical signals via optical fibres in legacy signal formats; and an electrical conversion circuit configured to convert the legacy signal formats to an internal signal format used by said network device.

Abstract: An optical communications system initiates automatic power reduction by selecting a portion of a Raman optical pumping signal from optical signals propagating on an optical fiber span. A signal related to a magnitude of the selected portion of the Raman optical pumping signal is generated. Power of at least one of the optical data signals and the optical pumping signals propagating in the optical fiber span is reduced in response to the generated signal.

Abstract: An optical communications system includes a plurality of optical fiber spans. An optical loss of one of the plurality of optical fiber spans is different from an optical loss of another one of the plurality of optical fiber spans. At least one of the plurality of optical fiber spans includes an optical loss that is greater than or equal to 35 dB and at least one of the plurality of optical fiber spans includes an optical loss that is less than 30 dB. An optical amplification system includes at least one discrete optical amplifier, at least one distributed optical amplifier, and an optical loss element. The optical amplification system has spectral gain that compensates for substantially all losses experienced by the optical signals propagating in the plurality of optical fiber spans.

Abstract: Optical communication systems, terminal facilities of an optical communication system, optical communication methods, and methods of communicating within an optical network are provided. According to one aspect of the invention, an optical communication system includes: a plurality of optical communication conduits individually configured to communicate data communication signals; an optical switch adapted to optically couple a communication path of an associated data terminal with at least one of the optical communication conduits; and a controller configured to monitor the data communication signals and to control the optical switch responsive to the monitoring of the data communication signals.

Abstract: A fiber optic communications link having PMD characterization across multiple optical channels to identify PMD problems. The communications link has adaptive PMD controls employed along the optical link, whereby PMD phenomena detected by instruments, such as PMD compensators, are interpreted as being either attributable to perturbation of fiber characteristics at large, or by failure of PMD equipment along the link. The present invention avoids taking unnecessary control or maintenance actions upon PMD related controllers and compensators. PMD notifications from various PMD compensators are correlated to identify which portion of the link has undergone a change in polarization characteristics to further identify PMD related errors and problems.

Abstract: A method and apparatus performing fault management in an optical communications system including a polarization mode dispersion (PMD) compensator. The method and apparatus utilizes a controller receiving notifications indicative of PMD in the system, as well as at least one indicator from a system device providing an indication of an attribute of the communication system. Such system devices include a receiver providing a Q factor and a bit error rate (BER) of an optical signal, and a signal-to-noise ratio meter providing an SNR of the optical signal. The method intelligently provides fault management by correlating the PMD notifications and system indicators to distinguish between fiber failure, PMD-related degradations, and failure of monitoring equipment itself.

Abstract: A fiber optic communications link having PMD characterization across multiple optical channels to identify PMD problems. The communications link has adaptive PMD controls employed along the optical link, whereby PMD phenomena detected by instruments, such as PMD compensators, are interpreted as being either attributable to perturbation of fiber characteristics at large, or by failure of PMD equipment along the link. The present invention avoids taking unnecessary control or maintenance actions upon PMD related controllers and compensators. PMD notifications from various PMD compensators are correlated to identify which portion of the link has undergone a change in polarization characteristics to further identify PMD related errors and problems.

Abstract: A method and apparatus performing fault management in an optical communications system including a polarization mode dispersion (PMD) compensator. The method and apparatus utilizes a controller receiving notifications indicative of PMD in the system, as well as at least one indicator from a system device providing an indication of an attribute of the communication system. Such system devices include a receiver providing a Q factor and a bit error rate (BER) of an optical signal, and a signal-to-noise ratio meter providing an SNR of the optical signal. The method intelligently provides fault management by correlating the PMD notifications and system indicators to distinguish between fiber failure, PMD-related degradations, and failure of monitoring equipment itself.

Abstract: A method and apparatus performing fault management in an optical communications system including a polarization mode dispersion (PMD) compensator. The method and apparatus utilizes a controller receiving notifications indicative of PMD in the system, as well as at least one indicator from a system device providing an indication of an attribute of the communication system. Such system devices include a receiver providing a Q factor and a bit error rate (BER) of an optical signal, and a signal-to-noise ratio meter providing an SNR of the optical signal. The method intelligently provides fault management by correlating the PMD notifications and system indicators to distinguish between fiber failure, PMD-related degradations, and failure of monitoring equipment itself.

Abstract: A fiber optic communications link having PMD characterization across multiple optical channels to identify PMD problems. The communications link has adaptive PMD controls employed along the optical link, whereby PMD phenomena detected by instruments, such as PMD compensators, are interpreted as being either attributable to perturbation of fiber characteristics at large, or by failure of PMD equipment along the link. The present invention avoids taking unnecessary control or maintenance actions upon PMD related controllers and compensators. PMD notifications from various PMD compensators are correlated to identify which portion of the link has undergone a change in polarization characteristics to further identify PMD related errors and problems.

Abstract: An all-optical system for regenerating a first optical signal carried in a first direction on an optical transmission medium and a second optical signal carried in a second direction on the optical transmission medium includes a bi-directional clock recovery loop and a bi-directional optical gate. The bi-directional clock recovery loop includes a first optical clock recovery circuit for recovering a first clock signal from the first optical signal and a second optical circuit for recovering a second clock signal from the second optical signal. The first and second optical circuits of the clock recovery loop share at least some common optical circuit elements. The bi-directional optical gate includes a first non-linear optical light mirror circuit for producing a first regenerated signal based on the first optical signal and the first clock signal and a second non-linear optical light mirror circuit for producing a second regenerated signal based on the second optical signal and the second clock signal.

Abstract: A bidirectional chromatic dispersion system includes an optical circulator that includes four ports. A first port is coupled to a first optical transmission medium and a third port is coupled to the second optical transmission medium. A first dispersion compensating grating is coupled to a second port, and a second dispersion compensating grating is coupled to a fourth port. The first dispersion compensating grating is operative to reflect wavelengths in a first optical band, and the second dispersion compensating grating is operative to reflect wavelengths in a second optical band. The first dispersion compensating grating is substantially transparent to wavelengths in the second optical band, and the second dispersion compensating grating is substantially transparent to wavelengths in the first optical band. The first dispersion compensating grating is coupled to the second port of the optical circulator through the second dispersion compensating grating and a dispersion compensating fiber.

Abstract: A dual-band optical amplifier uses a single pump source, such as a YAG solid-state laser emitting a pump light at a wavelength of 1047 nm, to provide amplification in both the 1550 nm and 1310 nm bands which are commonly encountered in the optical telecommunications environment. The pump light is fed into a fiber doped with praseodymium fluoride having Pr atoms in a +3 ionization state. These ions exhibit a ground state absorption that includes the 1047 nm wavelength. The same pump light is also coupled to a separate amplification fiber doped with trivalent erbium ions and ytterbium. This combination of ions also can be pumped to a metastable excited state by a 1047 nm wavelength source. Accordingly, when photon emission is generated, there is signal amplification in both fibers results.

Abstract: A polarization beam splitter separates the optical data signal into first and second orthogonally polarized optical signals. A first variable time delay element provides a first incremental propagation delay for the first polarized optical signal. A second variable time delay element provides a second incremental propagation delay for the second polarized optical signal. The first and second variable time delay elements consist of a series of optical switches optically interconnected by different incremental lengths of optical fiber. For example, 2.times.2 optical switches are provided for switching between a reference fiber segment and a respective delay fiber segment to provide a relative incremental propagation delay. A controller controls optical switches in the first and second variable switching delay elements to set first and second incremental propagation delays.

Abstract: A polarization mode compensation system and method using optical switch elements to establish incremental delays between different polarization modes of an optical data signal is provided. A polarization mode separator separates the optical data signal into first and second orthogonally polarized optical signals. A first variable switching delay element provides a first incremental propagation delay for the first polarized optical signal. A second variable switching delay element provides a second incremental propagation delay for the second polarized optical signal. The first and second variable switching delay elements consist of a series of optical switches optically interconnected by different incremental lengths of optical fiber. For example, 2.times.2 optical switches are provided for switching between a reference fiber segment and a respective delay fiber segment to provide a relative incremental propagation delay.

Abstract: An optical interface device dynamically reconfigures a telecommunications network. The device includes an optically switched backplane connected between two stages of an optical tapped amplifier. Various modules may be plugged into the backplane for performing selective processing of the optical signal without any signal conversion to electrical domain. The modules are electrically controlled by a controller, which is also a module, overseeing the operations upon the optical signal by other modules.