Patent ID: 6134036
Filing Date: 2000-10-17
Classification: H04J,H04Q

Abstract:
Method of dropping and adding channels to and from a line terminal that is connected to an optical add/drop-multiplexer node in order to communicate between said add/drop multiplexer node and at least one first and one second other optical node, comprising the steps of:providing a channel selective switch which is operable in bar and cross states,receiving, in the optical add/drop-multiplexer node, at least two optical multiplexed channels from the first other optical node,selecting a predetermined number of channels to be dropped to, and added from, the line terminal,dropping and adding the selected predetermined number of channels,passing non-selected channels through the optical add/drop-multiplexer node to said second other optical node,wherein the step of passing further comprises cross coupling said non-selected channels, which are received from the first other optical node, from a first optical input of the channel selective switch to a second optical output of said channel selective switch and equalizing power levels of the non-selected channels, from which second optical output the non-selected channels are supplied to the second other optical node.