Patent ID: 7389047
Filing Date: 2008-06-17
Classification: H04B,H04J

Abstract:
1. An optical transmission network comprising: a ring optical link and a concentrator having a send interface and a receive interface, wherein a first, upstream end of said link is connected to said send interface and a second, downstream end of said link is connected to said receive interface, the send interface comprises optical senders that produce “downlink” optical signals carried by respective wavelengths, the receiver interface comprises optical receivers that detect “uplink” optical signals coming from said second end, said link is subdivided into a plurality of segments separated by access nodes for optical receivers and optical senders of associated stations, said station senders produce said uplink optical signals carried by respective wavelengths, said optical receivers detect downlink optical signals selectively as a function of their respective wavelengths, each access node comprises coupling means that couple any optical signal coming from the segment on the upstream side of the node to the segment on the downstream side of the node and to the receivers of the associated station and to couple any optical signal coming from said senders of the associated station to the segment on the downstream side of the node, which couplings are not wavelength-selective, and said downlink optical signals are carried by wavelengths belonging to a first set of predefined wavelengths, wherein said network further comprises a rejection filter is inserted into a segment of said link between two adjacent nodes, said rejection filter rejects a portion of the wavelengths of said first set, and optical senders of stations associated with nodes on the downstream side of said segment produce uplink optical signals carried by respective wavelengths rejected by said rejection filter.