Abstract: The present invention includes a fast algorithm to compute the pre-equalized waveform for simultaneous compensation of the self-phase modulation and chromatic dispersion experienced by a high-speed optical signal, e.g., at 10 Gb/s, and shows that it is used for an automatic self-adapting pre-equalization when the knowledge on transmission link details is inaccurate or incomplete.

Abstract: A method and apparatus for transmitting optical pulses in a dispersion-managed optical transmission system comprises determining the pulse width of optical pulses in a optical transmission channel in accordance with the path-average dispersion (PAD) experienced by that channel.

Abstract: A repeater node for an optical transmission system provides amplification of optical signals and uses a modulated pump signal to transfer status information about the repeater node to a control system via an optical supervisory signal. The pump signal supplied by a pump source to an optical amplifier is modulated with one or more tones that are indicative of status in the repeater node. In a transmission fiber coupled to the output of the optical amplifier, the modulation of the pump signal is transferred to the supervisory signal of the optical transmission system as a result of Raman effect. More specifically, the pump wavelength and the supervisory signal wavelength are such that the modulated tone on the shorter wavelength pump signal is transferred to the longer wavelength supervisory signal. The tone can then be extracted from the supervisory signal and processed at another node in the system.

Abstract: A method and apparatus for mitigating intersymbol interference (ISI) from narrow-band optical filtering and improving transmission performance by filtering multichannel optical signals using an optical filter device that exhibits a desired loss ripple in the transmittance profile of the filter passband.

Abstract: A dispersion compensator apparatus including interleavers for de-interleaving/interleaving even and odd channels of a WDM signal, and dispersion compensation modules (DCMs) coupled between the interleavers. One or more of the DCMs is a periodic-group-delay (PGD) DCMs for providing dispersion compensation.

Abstract: An optical add/drop multiplexer (OADM) adapted to route optical signals having at least two different bit rates. The OADM has at least two sets of DWDM channels, e.g., with channels in a first set having a first bandwidth value suitable for the transmission of 10-Gb/s signals and channels in a second set having a second bandwidth value suitable for the transmission of 40-Gb/s signals. The first and second sets occupy two different spectral bands and the first set has two subsets of interleaved channels. In one embodiment, the OADM has first and second optical branches adapted to process optical signals corresponding to first and second groups of channels, respectively. The first group includes a first subset from the first set while the second group includes the second set and a second subset from the first set. Advantageously, OADMs of the invention may be used to create independent processing paths for different groups of channels. As a result, a communication system having those OADMs can be upgraded, e.g.

Abstract: An optical add/drop multiplexer (OADM) adapted to route optical signals having at least two different bit rates. The OADM has at least two sets of DWDM channels with channels in a first set having a first bandwidth value, e.g., suitable for the transmission of signals having a bit rate of 10 Gb/s, and channels in a second set having a second bandwidth value, e.g., suitable for the transmission of signals having a bit rate of 40 Gb/s. In one embodiment, the frequencies of the channels from the first set are interleaved with the frequencies of the channels from the second set, and the OADM has first and second optical branches adapted to process optical signals corresponding to the first and second sets, respectively. Initially, the OADM may be configured to process 10-Gb/s signals using the first optical branch only while leaving the second optical branch unutilized.

Abstract: A method, apparatus and system for reducing gain ripple in a Raman-amplified WDM system includes determining a gain profile of an optical signal transported via a first Raman amplification span in a Raman-amplified WDM system, comparing the determined gain profile to a gain profile of an optical signal transported via a second Raman amplification span, determining, from the comparison, an amount of wavelength adjustment required for a plurality of Raman pumps comprising at least one Raman pump block of the second Raman amplification span to alter the gain profile of an optical signal transported via the second Raman amplification span, such that a cumulative gain profile of an optical signal transported via the first and the second Raman amplification spans approaches a desired gain profile, and generating a control signal suitable for adjusting the wavelengths of the plurality of Raman pumps of the at least one Raman pump block an amount consistent with the determined amount.

Abstract: To facilitate routing changes, a telecommunications network (10, 10?, 10??) includes a centralized network routing database (28) queried by each ingress switch upon receipt of a call by a calling subscriber (12). In response to the query, the network routing database returns to the querying switch the identity on the next (downstream) switch in the routing path. The querying switch then translates the switch identity to establish the link to that next switch. Because each querying switch makes the necessary translation of the next switch identity to make the link to the next switch, the centralized network database need not concern itself with the particular characteristics of the switch. To make global routing changes, only the network routing database need be updated, not each individual switch.

Abstract: A repeater node for an optical transmission system provides amplification of optical signals and uses a modulated pump signal to transfer status information about the repeater node to a control system via an optical supervisory signal. The pump signal supplied by a pump source to an optical amplifier is modulated with one or more tones that are indicative of status in the repeater node. In a transmission fiber coupled to the output of the optical amplifier, the modulation of the pump signal is transferred to the supervisory signal of the optical transmission system as a result of Raman effect. More specifically, the pump wavelength and the supervisory signal wavelength are such that the modulated tone on the shorter wavelength pump signal is transferred to the longer wavelength supervisory signal.

Abstract: A method and apparatus for transmitting optical pulses in a dispersion-managed optical transmission system comprises determining the pulse width of optical pulses in a optical transmission channel in accordance with the path-average dispersion (PAD) experienced by that channel.

Abstract: The present invention concerns a technique for providing Class-of-Service Routing in an ATM network (10) that utilizes the Private Network-Network Interface (PNNI) protocol. An originating node seeking to route a call to a terminating node does so by initially determining the class-of-service and then selecting a shortest length path there-between. Each successive link on the selected path is examined for sufficient available bandwidth and available depth (i.e., bandwidth not reserved for other services) for the Class-of-Service of the call. If every link possesses sufficient available bandwidth, then the call passes on the selected path. Otherwise, should a link on the selected path lack sufficient bandwidth and available depth, then a crankback message is sent to the originating node, and the originating node selects the next shortest path. Thereafter, the process of examining each link for sufficient bandwidth is repeated. If no path is found, the call is ultimately blocked.

Abstract: A method, apparatus and system for reducing gain ripple in a Raman-amplified WDM system includes determining a gain profile of an optical signal transported via a first Raman amplification span in a Raman-amplified WDM system, comparing the determined gain profile to a gain profile of an optical signal transported via a second Raman amplification span, determining, from the comparison, an amount of wavelength adjustment required for a plurality of Raman pumps comprising at least one Raman pump block of the second Raman amplification span to alter the gain profile of an optical signal transported via the second Raman amplification span, such that a cumulative gain profile of an optical signal transported via the first and the second Raman amplification spans approaches a desired gain profile, and generating a control signal suitable for adjusting the wavelengths of the plurality of Raman pumps of the at least one Raman pump block an amount consistent with the determined amount.

Abstract: The priority of the flow of packets representing calls or other connection requests within a packet network (10) is determined from the Class-of-Service of the call. Upon receipt of a call, a recipient router (121, 122, 123) identifies available paths, typically by exchanging messages with the other routers in the network. After selecting the path, the recipient router or centralized bandwidth broker determines whether the links comprising the selected path have available bandwidth for the class of service of the call. If so, the router routes the call to the next hop along the path. Otherwise, the router selects another path(s) and checks whether the links on the path possess sufficient bandwidth for the class of service of the call.

Abstract: An originating switch (110) in a packet-based telecommunications network (100) routes calls to a terminating switch using the combination of Success-to-the Top (STT) and Class-of-Service criterion. In routing a call to the terminating switch, the originating switch 110 checks for available bandwidth for the class of service of the call on the direct path (116) between switches. If the path has available bandwidth, the originating switch routes on the direct path. Otherwise, the originating switch searches for the most recently successful one of a plurality the via switches (1181-118n) linking the originating and terminating switches to determine whether that via switch can successfully route the call to the terminating switch. If the most recently successful one of the via switches possesses available bandwidth to route the call in accordance with its class of service, the originating switch 110 selects that via switch to route the call.

Abstract: A method for transferring Web-based information over a network to a personal information management system includes selecting a set of Web-based information and creating a transfer request. The transfer request includes the set of Web-based information and an address for a sever associated with the personal information management system. The server is in communication with the network and has access to calendar and contact data for a set of users. The transfer request is sent to the server and the set of Web-based information is stored at the server and associated with at least one user from the set of users.

Abstract: A method for scheduling an event over a network in a calendar of an invitee includes creating a schedule request that includes at least a set of details of the event and an identifier if the event creator. The schedule request is sent to a server in communication with the network. The server has access to the calendar of the invitee and a calendar for the event creator. Upon receipt of the schedule request, an event record is created at the server that includes at least the set of details for the event and a link to the invitee's calendar. The event is also added to the calendar of the invitee. The schedule request may be created using a link associated with the event.

Abstract: A distortion analyzer for generating a distortion signal based on an input signal. For example, the distortion signal may be generated by adding a first signal corresponding to the entire spectrum of the input signal to a second signal corresponding to a low-frequency component of the input signal and then subtracting from the result of addition a third signal corresponding to a specific frequency band of the input signal. The effect of polarization mode dispersion that an optical signal experiences as it propagates through an optical transmission fiber may be compensated for at a receiver using a birefringent compensator, in which the distortion analyzer continuously examines the signal outputted by the compensator and supplies the distortion signal to the compensator, which causes the compensator to reduce the effect of such polarization mode dispersion based on the level of the distortion signal.

Abstract: A distortion analyzer for generating a distortion signal based on an input signal. For example, the distortion signal may be generated by adding a first signal corresponding to the entire spectrum of the input signal to a second signal corresponding to a low-frequency component of the input signal and then subtracting from the result of addition a third signal corresponding to a specific frequency band of the input signal. The effect of polarization mode dispersion that an optical signal experiences as it propagates through an optical transmission fiber may be compensated for at a receiver using a birefringent compensator, in which the distortion analyzer continuously examines the signal outputted by the compensator and supplies the distortion signal to the compensator, which causes the compensator to reduce the effect of such polarization mode dispersion based on the level of the distortion signal.

Abstract: The effect of polarization mode dispersion that an optical signal experiences as it propagates through an optical transmission fiber is compensated for at a receiver using a birefringent compensator, in which a distortion analyzer repeatedly examines the signal outputted by the compensator and causes the compensator to reduce the effect of such polarization mode dispersion based on the results of such examination.