Interconnections and protection between optical communications networks

Abstract

An optical communications system including a submarine optical communications system, a landing station associated with the submarine optical communications system, a terrestrial optical communications system, a point of presence associated with the terrestrial optical communications system, a first wavelength division multiplexed optical connection between the point of presence and the landing station, and a second wavelength division multiplexed optical connection between the point of presence and the landing station and routed diversely from the first wavelength division multiplexed optical connection.

1 . An optical communications system, comprising: 
 a submarine optical communications system;    a landing station associated with the submarine optical communications system;    a terrestrial optical communications system;    a point of presence associated with the terrestrial optical communications system;    a first wavelength division multiplexed optical connection between the point of presence and the landing station; and    a second wavelength division multiplexed optical connection between the point of presence and the landing station and routed diversely from the first wavelength division multiplexed optical connection.    
     
     
         2 . The system of  claim 1 , further comprising: 
 a first set of transmit equipment in the point of presence and associated with the first wavelength division multiplexed optical connection;    a second set of transmit equipment in the point of presence and associated with the second wavelength division multiplexed optical connection;    an optical switch in the point of presence and selectively connecting the first and second sets of transmit equipment to the terrestrial optical communications system.    
     
     
         3 . The system of  claim 2 , wherein the first and second sets of transmit equipment include transmitters/receivers.  
     
     
         4 . The system of  claim 3 , wherein the first and second sets of transmit equipment include WDM and optical conditioning units.  
     
     
         5 . The system of  claim 1 , further comprising an optical switch in the landing station for selectively connecting the submarine optical communications system to the first and second wavelength division multiplexed optical connections.  
     
     
         6 . The system of  claim 5 , further comprising at least one optical amplifier in the first and second wavelength division multiplexed optical connections.  
     
     
         7 . The system of  claim 1 , wherein optical signals undergo WDM in the point of presence and do not undergo WDM in the landing station.  
     
     
         8 . The system of  claim 1 , further comprising an optical splitter in the landing station for splitting optical signals from the submarine optical communications system and providing split optical signals to the first and second wavelength division multiplexed optical connections.  
     
     
         9 . The system of  claim 2 , wherein the optical switch in the point of presence includes channel level switches.  
     
     
         10 . A method of optical signal protection in an optical communications system including a submarine optical communications system and a terrestrial optical communications system, comprising: 
 providing optical communications signals between the submarine optical communications system and the terrestrial optical communications system via first and second wavelength division multiplexed optical connections;    routing the first and second wavelength division multiplexed optical connections on diverse paths so as to provide a working path and a protect path, on the first and second wavelength division multiplexed optical connections, for optical signals passing between the submarine and terrestrial optical communications systems;    detecting a fiber cut in the submarine optical communications system; and    bridging between the submarine optical communications system and the terrestrial optical communications system in response to detecting the fiber cut.    
     
     
         11 . The method of  claim 10 , further comprising providing protection switching between the terrestrial optical communications system and the submarine optical communications system.  
     
     
         12 . The method of  claim 11 , wherein providing bridging includes: 
 splitting optical signals received from the submarine optical communications system; and    providing split optical signals on the first and second wavelength division multiplexed optical connections.    
     
     
         13 . The method of  claim 11 , further comprising: 
 detecting a fiber cut in one of the first and second wavelength division multiplexed optical connections; and    routing optical signals between the submarine optical communications system and the terrestrial optical communications system on one of the first and second wavelength division multiplexed optical connections which is not cut.    
     
     
         14 . The method of  claim 11 , wherein WDM is performed between the submarine and terrestrial optical communications systems only at a point of presence, which is located between the terrestrial optical communications system and the first and second wavelength division multiplexed optical connections.  
     
     
         15 . An optical communications system, comprising: 
 a submarine optical communications system;    a first landing station associated with the submarine optical communications system;    a second landing station associated with the submarine optical communications system;    a submarine link between the first and second landing stations;    a terrestrial optical communications system;    a point of presence associated with the terrestrial optical communications system;    a first wavelength division multiplexed optical connection between the point of presence and the first landing station; and    a second wavelength division multiplexed optical connection between the point of presence and the second landing station.    
     
     
         16 . The system of  claim 15 , wherein: 
 the first landing station includes a first optical switch for selectively connecting the submarine optical communications system to one of the first wavelength division multiplexed optical connection and the submarine link; and    the second landing station includes a second optical switch for selectively connecting the submarine optical communications system to one of the second wavelength division multiplexed optical connection and the submarine link.    
     
     
         17 . The system of  claim 15 , wherein the submarine optical communications system includes a protection path which is routed through the first landing station, through the point of presence, and through the second landing station.  
     
     
         18 . The system of  claim 15 , wherein the submarine link includes at least one optical signal amplifier.  
     
     
         19 . The system of  claim 15 , wherein the submarine optical communications system has 1+1 protection and wherein the first and second landing stations interconnect the submarine and terrestrial optical communications systems.  
     
     
         20 . The system of  claim 16 , wherein the submarine link provides a shared transit link during reconfiguration of at least one of the first and second optical switches.