US 9,813,185 B2
WDM single fiber ring protection
Fabio Cavaliere, Pisa (IT); and Alberto Bianchi, Pisa (IT)
Assigned to Telefonaktiebolaget LM Ericsson (publ), Stockholm (SE)
Appl. No. 14/903,676
Filed by Telefonaktiebolaget L M Ericsson (publ), Stockholm (SE)
PCT Filed Jul. 10, 2013, PCT No. PCT/EP2013/064594
§ 371(c)(1), (2) Date Jan. 8, 2016,
PCT Pub. No. WO2015/003746, PCT Pub. Date Jan. 15, 2015.
Prior Publication US 2016/0173225 A1, Jun. 16, 2016
Int. Cl. H04J 14/00 (2006.01); H04J 14/02 (2006.01); H04B 10/032 (2013.01); H04Q 11/00 (2006.01)
CPC H04J 14/0287 (2013.01) [H04B 10/032 (2013.01); H04Q 11/0062 (2013.01); H04Q 2011/0081 (2013.01); H04Q 2011/0092 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A node for a single fiber bidirectional WDM optical ring network, the node having:
a first optical protection switch having first and second ports for coupling to respective first and second adjacent portions of the single fiber bidirectional ring, while providing a pass through optical path for wavelengths on the bidirectional ring to pass between the first and second adjacent portions,
the first optical protection switch also having a further port for coupling to an external optical path, external to the bidirectional ring,
the first optical protection switch having a control input for receiving an indication of fault in the bidirectional ring, and
the optical protection switch being operable to selectively couple the further port to the first port and the second port according to the indication of a fault, so as to selectively provide a bidirectional working path between the further port and the first port and a bidirectional protection path between the further port and the second port, and so as to maintain the same optical path on the bidirectional ring for both directions of the bidirectional selected wavelengths.