Abstract: A demultiplexer/multiplexer is disclosed wherein an arrayed waveguide grating having a reflector at an end includes selectable signal path blockers. The arrayed waveguide device has a common input/output port for launching radiation in the form of an input signal having n wavelengths therein and for receiving back via the reflector at the input/output port a selected channel of the input signal. In operation a multiplexed signal have n channels is launched therein and a selected channel is output for analysis or further processing.

Abstract: A method of distributing IP routing information between elements of an optical ring or spur network for network management, the method comprising the step of assigning a control interface module to each network element, wherein each interface module has first and second point-to-point link ports to its two neighbouring interface modules respectively, and assigning an IP address and sub-netmask to each link port.

Abstract: An optical network element having a management unit for receiving a management signal. The management unit includes at least two substantially identical management components.

Abstract: An optical network comprising a network management station, at least one source network element associated with the network management station, and at least one destination network element, wherein the source network element comprises a source proxy for sending an OSC signal in the form of IP datagrams to the destination network element under the control of the management station, the source proxy being arranged in a manner such that, in use, it sends duplicate IP datagrams along two different optical paths to the destination network element, and wherein the destination network element comprises a destination proxy arranged to pass one of the duplicate IP datagrams into the destination network element for processing and to filter out for disposal the other one.

Abstract: An optical network element for use in an optical network, the network element including a processing unit capable of running a Unix® operating system and adapted, in use, to effect at least one management function associated with the network element. (Unix® is a registered trade mark of The Open Group.

Abstract: An optical network arranged in a manner such that in use at least one management function in the optical network is being effected utilising standard TCP/IP communication protocols.

Abstract: A method for high resolution trimming of PCB components, such as capacitors, inductors, transmission lines, transformers, antennas, resistors, etc. The method includes drilling or milling the PCB to effect the electrical characteristics of the component. The actual component can be machined to reduce the size of the component, or electrical connections to the component can be severed. The method can be used to set the capacitance of a tuning capacitor for an oscillator circuit. The tuning capacitor is etched out of the conductive planes on opposing sides of the PCB. The dielectric substrate of the PCB acts as the dielectric for the capacitor. The conductive planes are also etched to define conductive traces and connection pads suitable for surface mounting and electrically connecting the various electrical components on the PCB. The area of the selectively etched capacitive plates has a capacitance that is predetermined.