Global Patent Index - EP 0979564 A2

EP 0979564 A2 2000-02-16 - 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

EP 0979564 A2 (EN)

Application

EP 98920810 A

Priority

  • SE 9800801 W
  • SE 9701668 A

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 (main, further and additional classification)

H04J 14/02

IPC 8 full level (invention and additional information)

H04J 14/02 (2006.01)

CPC (invention and additional information)

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 9849794A3

Designated contracting state (EPC)

AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

EPO simple patent family

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

INPADOC legal status


2009-09-30 [18D] DEEMED TO BE WITHDRAWN

- Effective date: 20090407

2004-12-29 [17Q] FIRST EXAMINATION REPORT

- Effective date: 20041110

2004-05-06 [RAP1] TRANSFER OF RIGHTS OF AN EP PUBLISHED APPLICATION

- Owner name: TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

2000-07-12 [RBV] DESIGNATED CONTRACTING STATES (CORRECTION):

- Designated State(s): AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

2000-02-16 [17P] REQUEST FOR EXAMINATION FILED

- Effective date: 19991009

2000-02-16 [AK] DESIGNATED CONTRACTING STATES:

- Kind Code of Ref Document: A2

- Designated State(s): AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE