Abstract: An optical amplifier with optical gain-control (OGC) has an input (11) for the signals to be amplified and an output (12) for the amplified signals. It comprises in series a first Bragg grating (BG) (15), a variable optical attenuator (VOA) (17), an optical amplification unit with pump (13) and a second Bragg grating (BG) (14). The two gratings define between them a laser cavity with the amplification unit (13) in the middle and the signals to be amplified are placed at the input of the amplification unit (13) with a splitter (16) at the input of the amplification unit. A network with nodes comprising said amplifiers is also described.

Abstract: The invention relates to a communications node (10, 90, 100) for routing a plurality of Wavelength Division Multiplexed (WDM) optical signals, the node having a plurality of line units (12) between its inputs and outputs, each line unit including a splitter (14) and a Wavelength Selective Switch (WSS) (16), wherein the splitter (14) is arranged to split an incoming WDM signal into a plurality of WDM signals and to pass them to each WSS in the plurality of line units, each WSS (16) being arranged to selectively route any one or more channels of its received WDM signals to its associated output. Such an arrangement has the advantage of providing a more cost effective realisation of a node with a high nodal degree. The invention provides a technical solution to the problem of connecting a plurality of inputs to a plurality of outputs in a multi-port WDM node. The node has particular application in a mesh network where the nodal degree may be high.