EP 0979564 A2 20000216 - LOW LOSS, OPTICAL ADD/DROP WDM NODE
Title (en)
LOW LOSS, OPTICAL ADD/DROP WDM NODE
Title (de)
OPTISCHER EINFÜGE-/AUSFÜGE-KNOTEN MIT NIEDRIGEN VERLUSTEN
Title (fr)
NOEUD OPTIQUE DE MULTIPLEXAGE PAR REPARTITION EN LONGUEUR D'ONDE D'ADDITION ET D'EXTRACTION A PERTE BASSE
Publication
Application
Priority
- SE 9800801 W 19980430
- SE 9701668 A 19970430
Abstract (en)
[origin: WO9849794A2] An add/drop (7) node for an optical fiber network of WDM type has preamplifiers (19, 21) connected to the input fibers (3, 11). Part of the incoming signal power is tapped off by means of drop couplers or splitters (47, 49) and the tapped-off power is provided to a demultiplexer (51) where WDM information channels to be extracted from the network in the node are separated from each other and then fed to opto-electrical receivers (15). WDM information channels to be added in the node from electro-optical transmitters (17) are first combined in a multiplexer (61), the resulting signal being provided to add couplers (57, 59) to which also the signals incoming to the node are provided so that a combined signal is obtained for transmission to the opposite side of the node (7). Channels are thus added in the node to channels passing substantially ininterruptedly through the node. In order to have a low attenuation of the passing signals, the power per channel in the added signal is given approximately the same level as the power of each passing channel by an optical amplifier (65, 67) arranged in the input line to the add coupler from the multiplexer (61). By this arrangement it is possible to maintain a low attenuation of the passing signals within the optical add/drop node, since no extra attenuating devices are needed for the light signal containing the passing channels. The signal to noise ratio of these channels can thus be kept high.
IPC 1-7
IPC 8 full level
H04J 14/02 (2006.01)
CPC (source: EP)
H04J 14/0204 (2013.01); H04J 14/0205 (2013.01); H04J 14/0206 (2013.01); H04J 14/0213 (2013.01)
Citation (search report)
See references of WO 9849794A2
Designated contracting state (EPC)
AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
DOCDB simple family (publication)
WO 9849794 A2 19981105; WO 9849794 A3 19990204; AU 7356298 A 19981124; EP 0979564 A2 20000216; SE 519255 C2 20030204; SE 9701668 D0 19970430; SE 9701668 L 19981031
DOCDB simple family (application)
SE 9800801 W 19980430; AU 7356298 A 19980430; EP 98920810 A 19980430; SE 9701668 A 19970430