Abstract: A local area network is used to interconnect media equipment, such as telephones, VoIP telephones, a media server, etc., located at geographically distributed sites of an optical communication system. The local area network may be implemented within an optical services channel carried by a WDM optical communication link. This may provide the needed connectivity at low costs and may allow conference calls to be accommodated.

Abstract: A network node structure for an optical communications network has a housing having a plurality of slots, and a plurality of cards inserted in the slots. The plurality of cards includes at least one first card having an optical input for receiving an input WDM optical signal from an optical line of the network, a first optical device for extracting at least one component optical signal at a wavelength from the input WDM optical signal and at least one optical output making available the at least one component optical signal. At least one second card is provided, distinct from the first card, having at least one socket mechanically and electrically adapted to receive one of a plurality of interchangeable electro-optical components.

Abstract: Communicating a signal includes receiving the signal at a primary device of a switching system, where the primary device is associated with a primary path along which the signal is propagating. A primary overmodulation signal associated with the primary path is generated. The absence of the primary overmodulation signal is detected, and an operating signal is sent from the primary device to a secondary device of the switching system, where the secondary device is associated with a secondary path. The operating signal operates to initiate propagation of the signal along the secondary path.

Abstract: An autoprotected optical communication ring network includes a first and a second optical carrier having opposite transmission directions and a plurality of optically reconfigurable nodes optically connected along the first and the second optical carrier and adapted to communicate in pairs on links susceptible to failure, the ring network having a normal operative condition in which the nodes of each pair are optically configured so as to exchange optical signals on a working arc path at a respective first wavelength (?x) on the first carrier and at a respective second wavelength (?y) different from the first wavelength (?x) on the second carrier, the working path having a complementary arc path defining a protection arc path in which the first wavelength (?x) on the first carrier and the second wavelength (?y) on the second carrier can be used for further links.

Abstract: An autoprotected optical communication ring network is disclosed. The ring network includes two optical carriers that are arranged for bidirectional transmission. Multiple optically reconfigurable nodes are connected along the optical carriers. The nodes communicate in pairs, defining non-overlapping working links. Under normal conditions, the nodes of each pair are optically configured to exchange optical signals over the working link at a first wavelength on the first carrier and at a second wavelength that is different from the first wavelength on the second carrier. During a failure condition, the first wavelength on the second carrier and the second wavelength on the first carrier are reserved for effecting a protection scheme, while the first wavelength on the first carrier and the second wavelength on the second carrier can still be used for unaffected working links.

Abstract: Systems and methods for reliable and low cost optical connection verification. One application is verification and monitoring of optical cross-connect performance. A connection is verified by splitting off optical signals at both ports of the connection, converting the signals to electrical signals, and then cross-correlating to verify connectivity between the ports. Lowpass filtering applied to the electrical signals may be applied to reduce the complexity of the cross-correlation.

Abstract: A closed-ring transparent optical communication network that provides for protection of the principal communication channel of each supported wavelength and supports occasional traffic on a separate channel. In the case of a breakdown of or degradation in the principal channel, these communications are redirected to the occasional channel.

Abstract: Communicating a signal includes receiving the signal at a primary device of a switching system, where the primary device is associated with a primary path along which the signal is propagating. A primary overmodulation signal associated with the primary path is generated. The absence of the primary overmodulation signal is detected, and an operating signal is sent from the primary device to a secondary device of the switching system, where the secondary device is associated with a secondary path. The operating signal operates to initiate propagation of the signal along the secondary path.

Abstract: An optical communication system for communicating at least a first optical system. The optical communication system includes a first primary guided optical path and a first secondary guided optical path, through each of which the first optical signal is configured to propagate. A first primary optical amplifier is provided in the first primary guided optical path and is configured to transmit an overmodulation frequency of the first optical signal. A first secondary optical amplifier is provided in the first secondary guided optical path and is configured to transmit the overmodulation frequency of the first optical signal. A controller controls propagation of the first optical signal from the first primary guided optical path to the first secondary guided optical path based on the detected presence of the overmodulation frequency.

Abstract: An optical self-healing-ring communication network is described which includes: a first optical communication line, forming a closed optical path; at least two add/drop nodes for optical signals, optically connected along the line; a second optical communication line forming a closed optical path and optically connected to the optical-signal add/drop nodes. Defined in the network are first and second mutually opposite. travel directions of the optical signals, with respect to the position of the optical-signal add/drop nodes. At least one of said nodes further comprises selection means, controlled by the optical signals, for the selective dropping of the optical signals from one of the communication lines. At least one of the optical-signal add/drop nodes further includes means for the simultaneous input of at least one optical signal in the first direction along the first communication line and in the second direction along the second communication line.

Abstract: A closed-ring transparent optical communication network that provides for protection of the principal communication channel of each supported wavelength and supports occasional traffic on a separate channel. In the case of a breakdown of or degradation in the principal channel, these communications are redirected to the occasional channel.

Abstract: An autoprotected optical communication ring network includes a first and a second optical carrier (2, 3) having opposite transmission directions and a plurality of optically reconfigurable nodes (20a-20f) optically connected along the first and the second optical carrier (2, 3) and adapted to communicate in pairs by means of respective links susceptible of failure, the ring network having a normal operative condition in which the nodes of each pair are optically configured so as to exchange optical signals on a respective working arc path at a respective first wavelength (&lgr;x) on the first carrier (2) and at a respective second wavelength (&lgr;y) different from the first wavelength (&lgr;x) on the second carrier (3), the respective working path having a complementary arc path defining a respective protection arc path in which the first wavelength (&lgr;x) on the first carrier (2) and the second wavelength (&lgr;y) on the second carrier (3) can be used for further links and the first wavelength (&lgr;x) on

Abstract: An optical self-healing-ring communication network is described which include: a first optical communication line, forming a closed optical path; at least two add/drop nodes for optical signals, optically connected along the line; a second optical communication line forming a closed optical path and optically connected to the optical-signal add/drop nodes. Defined in the network are first and second mutually opposite travel directions of the optical signals, with respect to the position of the optical-signal add/drop nodes. At least one of said nodes further comprises selection means, controlled by the optical signals, for the selective dropping of the optical signals from one of the communication lines. At least one of the optical-signal add/drop nodes further include means for the simultaneous input of at least one optical signal in the first direction along the first communication line and in the second direction along the second communication line.