Abstract: A terminal multiplexer structure comprising a plurality of line interface cards and a plurality of trunk interface cards wherein each of the line interface cards is connected to at least two of the trunk interface cards and comprises a switch for switching the connection transmission from the line interface board between the two trunk interface cards.

Abstract: A WDM add/drop module for use in a network node of an optical network, the module comprising an optical drop unit for dropping a first wavelength signal travelling along a first path in the optical network traffic, a trunk receiver unit for converting the first wavelength signal into a first electrical signal, a tributary optical transmitter unit for converting an electrical input signal into a first optical signal for transmission along a tributary optical connection, wherein the output of the trunk receiver unit is connected to the tributary optical transmitter unit and to a first interface port of the WDM drop module for interfacing with another WDM drop unit, an electrical switch unit arranged in a manner such that, in use, selectively either the first electrical signal or a second electrical signal received at a second interface port of the WDM add/drop module from another WDM add/drop module is through connected to the tributary transmitter unit for conversion and transmission along the tributary optica

Abstract: A casing member for a WDM add/drop multiplexer unit, the casing member comprising a backplane for interconnection of components of the WDM add/drop multiplexer unit inserted in the casing member, and at least one heat sink opening formed in a wall of the casing member disposed to, in use, receive a heat sink structure of a component of the WDM add/drop multiplexer unit in a manner such that the heat sink structure is exposed to an ambient around the casing member when the component is mounted in the casing member, for facilitating maintaining a controlled temperature environment inside of the component.

Abstract: A chassis member for carrying at least one circuit board for use in a WDM add/drop multiplexer unit, wherein the chassis member is adapted, in use, to function as a heatsink for a heat generating component mounted on the circuit board.

Abstract: A casing member for a WDM add/drop multiplexer unit, the casing member comprising a backplane for interconnection of components of the WDM add/drop multiplexer unit inserted in the casing member, and at least one heat sink opening formed in a wall of the casing member disposed to, in use, receive a heat sink structure of a component of the WDM add/drop multiplexer unit in a manner such that the heat sink structure is exposed to an ambient around the casing member when the component is mounted in the casing member, for maintaining a controlled temperature environment inside of the component.

Abstract: A WDM-to-switch interface unit comprising a WDM multiplexer/demultiplexer (mux/demux) for interfacing to a WDM optical network, a switch interface element for interfacing to an external switch unit, and a first conversion component disposed between the WDM mux/demux and the switch interface element for converting one or more layers of a management protocol in the optical network into corresponding layers of a management protocol of the external switch unit.

Abstract: An optical network element comprising a plurality of subscriber line connections, a WDM unit having a plurality of WDM channel connections, a plurality of subscriber line interface cards and a plurality of trunk line interface cards for optical interfacing between the subscriber line connections and the WDM channel connections, and a switch arranged, in use, in a manner such as to be capable of switching transmission directions between the WDM channel connections and individual ones of the subscriber line connections by suitable switching of an optical path configuration between transmitter ports and receiver ports of the subscriber line interface cards and the WDM channel connections.

Abstract: A linear or bus optical network comprising first and second end nodes and a plurality of primary nodes disposed, in use, between the end nodes, wherein each end node is connected to its nearest neighbouring primary node and its 2nd nearest neighbouring primary node, and wherein each primary node is connected to its 2nd nearest neighbouring primary or end node on either side, or, where one of its nearest neighbouring nodes is one of the end nodes, to said one end node and to its 2nd nearest neighbouring primary or end node on the other side.

Abstract: An electro-optic interface structure for use in a multi-protocol OEO WDM network, the interface structure comprising a rate multiplying encoding unit for applying a rate multiplying line code to an electrical transmit data signal prior to conversion of the electrical transmit data signal into an optical WDM channel signal, and a rate dividing decoding unit for applying a corresponding rate dividing line code to an electrical receive data signal converted from a received optical WDM channel signal, wherein the encoding unit is arranged such that, in use, the same rate multiplying line code can be applied to electrical transmit data signals of different protocols, and wherein the decoding unit is arranged such that, in use, the application of the same corresponding rate dividing line code can create electrical signals of different protocols.

Abstract: A diagnostic monitoring system for a WDM network, the system comprising an electrical non-blocking cross-connect switch having a plurality of demultiplexer ports, a plurality of multiplexer ports, at least one tributary receiver port, at least one tributary transmitter port, and at least one diagnostic port; and at least one multi-protocol performance monitoring unit connected to one of said at least one diagnostic ports such that said at least one multi-protocol performance monitoring unit, in use, can selectively monitor one of said demultiplexer or tributary receiver ports whereby said system, in use, supports multi-protocol intrusive monitoring of a test signal and multi-protocol non-intrusive monitoring of live traffic at said at least one demultiplexer or tributary receiver port

Abstract: A node for use in a WDM optical network, the node comprising a tributary receiver unit for receiving a data signal distributed via the WDM optical network and destined for said node, a path protection switching unit for switching receipt of said data signal at the tributary receiver unit from a working path to a protection path of the WDM optical network, and a control unit for the path protection unit, wherein the control unit comprises a multi rate clock data recovery (CDR) device arranged, in use, to detect a loss of lock (LOL) in the data signal received at the tributary receiver unit based on a comparison of an actual data rate received and a pre-programmed reference rate for said data signal.

Abstract: A method of cancelling crosstalk between a primary and a secondary signals contained in a FDM signal, wherein the primary signal comprises a binary encoded signal and the secondary signal has a lower signal amplitude than the primary signal, the method comprising the steps of (a) applying 2R and/or 3R regeneration to a primary signal recovery portion of the FDM signal for obtaining an estimate of the primary signal, and (b) utilising at least a portion of the estimated primary signal to substantially remove a primary signal contribution in a secondary signal recovery portion of the FDM signal for recovering the secondary signal.

Abstract: A network element for use in a multi-protocol WDM network, the network element comprising a rate multiplying encoding unit for applying a rate multiplying line code to an electrical transmit data signal prior to conversion of the electrical transmit data signal into an optical WDM channel data signal, a rate dividing decoding unit for applying a corresponding rate dividing line code to an electrical receive data signal converted from a received optical WDM channel data signal, and a management unit arranged, in use, to generate an embedded operational channel (EOC) signal in a portion of a bandwidth of the WDM channel for transmission of network management data, wherein the encoding unit is arranged such that, in use, the rate multiplying line code is not applied if the electrical transmit data signal is of a protocol satisfying a threshold condition and is applied if the electrical transmit data signal is of a protocol not satisfying the threshold condition, wherein the decoding unit is arranged such that, i

Abstract: A casing member for a WDM add/drop multiplexer unit, the casing member comprising a backplane for interconnection of components of the WDM add/drop multiplexer unit inserted in the casing member, and at least one heat sink opening formed in a wall of the casing member disposed to, in use, receive a heat sink structure of a component of the WDM add/drop multiplexer unit in a manner such that the heat sink structure is exposed to an ambient around the casing member when the component is mounted in the casing member, for facilitating maintaining a controlled temperature environment inside of the component.

Abstract: A chassis member for carrying at least one circuit board for use in a WDM add/drop multiplexer unit, wherein the chassis member is adapted, in use, to function as a heatsink for a heat generating component mounted on the circuit board.

Abstract: A casing member for a WDM add/drop multiplexer unit, the casing member comprising a backplane for interconnection of components of the WDM add/drop multiplexer unit inserted in the casing member, and at least one heat sink opening formed in a wall of the casing member disposed to, in use, receive a heat sink structure of a component of the WDM add/drop multiplexer unit in a manner such that the heat sink structure is exposed to an ambient around the casing member when the component is mounted in the casing member, for maintaining a controlled temperature environment inside of the component.

Abstract: A WDM add/drop module for use in a network node of an optical network, the module comprising an optical drop unit for dropping a first wavelength signal travelling along a first path in the optical network traffic, a trunk receiver unit for converting the first wavelength signal into a first electrical signal, a tributary optical transmitter unit for converting an electrical input signal into a first optical signal for transmission along a tributary optical connection, wherein the output of the trunk receiver unit is connected to the tributary optical transmitter unit and to a first interface port of the WDM drop module for interfacing with another WDM drop unit, an electrical switch unit arranged in a manner such that, in use, selectively either the first electrical signal or a second electrical signal received at a second interface port of the WDM add/drop module from another WDM add/drop module is through connected to the tributary transmitter unit for conversion and transmission along the tributary optica

Abstract: A WDM add/drop multiplexer structure comprising a plurality of WDM laser assemblies, wherein the WDM add/drop structure is arranged, in use, in a manner such that a controlled temperature environment is created around laser sources of the laser assemblies, and in a manner such as to be capable of creating the controlled temperature environment around the laser sources while the WDM add/drop multiplexer structure is subjected to an outside temperature ambient experienced in an Outside plant (OSP) situation.

Abstract: A network node for use in a WDM communications network, the network node comprising a first network interface unit arranged, in use, to demultiplex an incoming WDM optical signal and to convert the incoming WDM optical signal into a plurality of electrical channel signals, a regeneration unit for regenerating the electrical channel signals utilizing at least 2R regeneration, a second network interface unit arranged, in use, to convert and multiplex at least one of the electrical channel signals into an outgoing WDM optical signal, and a secondary interface unit arranged, in use, to convert at least one of the electrical channel signals into an optical signal and to drop the optical signal at the network node.

Abstract: An optical network node. A plurality of subscriber line connections. A WDM unit has a plurality of WDM channel connections connected to corresponding ones of the subscriber line connections and are arranged, in use, to multiplex optical signals carried on selected transmission connections of the WDM channel connections onto a trunk optical network connection. The WDM unit is arranged in a manner such that, in use, each transmission connection filters a specific wavelength associated with that transmission connection, whereby cross talk between the WDM channel connections is reduced.