Single Fiber Passive Optical Network Wavelength Division Multiplex Overlay

Abstract

A downstream baseline optical signal generated by a baseline optical link is combined with a second optical signal generated by an additional optical link to generate a broadband optical signal. A fiber optic network splits the broadband optical signal to a plurality of fiber drops. An optical network termination unit receives the broadband optical signal from the fiber drop and isolates the downstream baseline optical signal and the second downstream optical signal from the broadband optical signal. An upstream baseline optical signal may also be transmitted through the fiber drop by the optical termination unit. The optical termination unit does not effect baseline optical service to any other optical termination unit in the fiber optic network.

1 . An optical network termination unit, comprising: 
 a first filter operable to receive a broadband optical signal from a fiber drop, the broadband optical signal including a downstream baseline optical signal combined with a second downstream optical signal, the first filter operable to isolate the second downstream optical signal from the broadband optical signal;    a second filter operable to isolate the downstream baseline optical signal from a remaining portion of the broadband optical signal after the second downstream optical signal has been isolated from the broadband optical signal.    
     
     
         2 . The optical network termination unit of  claim 1 , wherein the second downstream optical signal is a T-Band signal.  
     
     
         3 . The optical network termination unit of  claim 2 , further comprising: 
 a wave division multiplexer that separates the T-Band signal from the broadband optical signal and demultiplexes the T-Band signal.    
     
     
         4 . The optical network termination unit of  claim 1 , wherein the second downstream optical signal is an L-Band signal.  
     
     
         5 . The optical network termination unit of  claim 4 , further comprising: 
 a wave division multiplexer that separates the L-Band signal from the broadband optical signal and demultiplexes the L-band signal.    
     
     
         6 . The optical network termination unit of  claim 1 , further comprising: 
 a converter unit operable to receive an upstream baseline signal and convert the upstream baseline signal into an upstream baseline optical signal.    
     
     
         7 . The optical network termination unit of  claim 6 , wherein: 
 the upstream baseline optical signal is within an optical bandwidth different from an optical bandwidth of the downstream baseline optical signal and an optical bandwidth of the second downstream optical signal;    the upstream baseline optical signal, the downstream baseline optical signal, and the second downstream optical signal are transmitted through the fiber drop.    
     
     
         8 . The optical network termination unit of  claim 6 , further comprising: 
 a converter unit operable to receive a second upstream signal and convert the second upstream signal into a second upstream optical signal, the second upstream optical signal being combined with the upstream baseline optical signal for transmission through the fiber drop.    
     
     
         9 . The optical network termination unit of  claim 8 , wherein the converter unit generates the second upstream optical signal in a T-band signal format.  
     
     
         10 . The optical network termination unit of  claim 8 , wherein the converter unit generates the second upstream optical signal in a L-band signal format.  
     
     
         11 . A method for upgrading a passive optical network, comprising: 
 receiving a broadband optical signal from a fiber drop, the broadband optical signal including a downstream baseline optical signal combined with a second downstream optical signal;    isolating the second downstream optical signal from the broadband optical signal;    isolating the downstream baseline optical signal from a remaining portion of the broadband optical signal after the second downstream optical signal has been isolated from the broadband optical signal.    
     
     
         12 . The method of  claim 11 , further comprising: 
 the second downstream optical signal is a T-Band signal;    separating the T-Band signal from the broadband optical signal.    
     
     
         13 . The method of  claim 12 , further comprising: 
 demultiplexing the T-Band signal.    
     
     
         14 . The method of  claim 11 , further comprising: 
 the second downstream optical signal is an L-Band signal;    separating the L-Band signal from the broadband optical signal.    
     
     
         15 . The method of  claim 14 , further comprising: 
 demultiplexing the L-Band signal.    
     
     
         16 . The method of  claim 11 , further comprising: 
 passing an upstream signal through the fiber drop.    
     
     
         17 . A system for upgrading a passive optical network, comprising: 
 means for receiving a broadband optical signal from a fiber drop, the broadband optical signal including a downstream baseline optical signal combined with a second downstream optical signal;    means for isolating the second downstream optical signal from the broadband optical signal;    means for isolating the downstream baseline optical signal from a remaining portion of the broadband optical signal after the second downstream optical signal has been isolated from the broadband optical signal.    
     
     
         18 . The system of  claim 17 , further comprising: 
 means for passing an upstream signal through the fiber drop on a separate bandwidth from the downstream baseline optical signal and the second downstream optical signal.    
     
     
         19 . The system of  claim 17 , further comprising: 
 means for separating a third downstream optical signal from the broadband optical signal, the third downstream optical signal being a T-band signal transmitted on a separate bandwidth from the downstream baseline optical signal and on a separate bandwidth from the second downstream optical signal.    
     
     
         20 . The system of  claim 18 , further comprising: 
 means for separating a fourth downstream optical signal from the broadband optical signal, the fourth downstream optical signal being a L-band signal transmitted on a separate bandwidth from the downstream baseline optical signal, the second downstream optical signal, and the third downstream optical signal.