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 system comprising a first WDM module having a first multiplexer unit for multiplexing a WDM optical signal, a second WDM module having a first demultiplexer unit for demultiplexing the WDM optical signal, and wherein the system is arranged, in use, such that optical losses experienced by individual channels of the WDM optical signal in the first multiplexing unit and the first demultiplexing unit and optical losses experienced by the channels during un-amplified transmission between the first and second WDM modules are substantially balanced.

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 WDM assembly comprising a WDM filter structure for multiplexing and demultiplexing optical signals and having a single fibre common connection for transmitting and receiving a WDM optical signal; a housing member for the WDM filter structure; a plurality of E/O transmitter units external to the housing member for receiving a plurality of independent electrical data signals and converting into a plurality of corresponding optical WDM channel signals; plurality of O/E receiver units external to the housing member for receiving a plurality of optical WDM channel signals and converting into a corresponding plurality of independent electrical data signals; wherein each of the E/O transmitter units and O/E receiver units is optically connected to the WDM filter structure via a single fibre link; and wherein excess fibre length in each fibre link is accommodated within the housing member, whereby each fibre length has a predetermined external fibre length between the housing member and the E/O transmitter units an

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.