Methods and Systems for Increasing Reach and/or Split in Passive Optical Networks

Abstract

Systems and methods according to these exemplary embodiments provide for methods and systems that allow for either reducing signal loss or improving the optical signal strength in a PON for increasing optical signal range.

What is claimed is: 
     
         1 . A method for equalizing optical signals comprising the steps of:
 receiving a plurality of upstream optical signals in a passive optical network (PON), each of said plurality of optical signals comprising a PON burst frame transmitted from a different downstream transmitter;   receiving schedule information for each of said plurality of optical signals, wherein said schedule information includes at least timing and power information associated with said plurality of optical signals; and   adjusting each of said plurality of optical signals by either amplifying or attenuating each of said plurality of optical signals based upon said schedule information to mitigate non-uniform signal powers of said PON burst frames.   
     
     
         2 . The method of  claim 1 , wherein said adjusting step is performed using a micro-mechanical optical attenuator, wherein a scheduler adjusts said micro-mechanical optical attenuator based upon a known strength of a next to be received optical signal from said plurality of optical signals. 
     
     
         3 . The method of  claim 1 , wherein said step is performed using parametric amplification with a variable pump laser, wherein a scheduler adjusts said parametric amplification with a variable pump laser based upon a known strength of a next to be received optical signal from said plurality of optical signals. 
     
     
         4 . The method of  claim 1 , wherein said step of adjusting is performed at a location other than at an optical line termination or a coupler/splitter in an optical communication system. 
     
     
         5 . A method for optical communications comprising the steps of:
 receiving, at an optical line termination, a plurality of optical signals from a plurality of upstream locations at an optical power equalizer within said optical line termination;   equalizing said plurality of optical signals from said plurality of upstream locations at said power equalizer, wherein said step of equalizing further comprises:
 splitting off a portion of each of said plurality of optical signals; 
 measuring an amplitude for each said portion of said plurality of optical signals; and 
 adapting each of said plurality of optical signals based on a corresponding, measured amplitude by either amplifying or attenuating each of said plurality of optical signals to generate equalized signals; and 
   transmitting said equalized signals to a receiving unit within said optical line termination.   
     
     
         6 . A node for equalizing optical signals comprising:
 an input port for receiving a plurality of upstream optical signals, each of said plurality of optical signals comprising a PON burst frame transmitted from a different downstream transmitter;   a scheduler for receiving schedule information for each of said plurality of optical signals, wherein said schedule information includes at least timing and power information associated with said plurality of optical signals, and   an adjuster for adjusting each of said plurality of optical signals by either amplifying or attenuating each of said plurality of optical signals based upon said schedule information to mitigate non-uniform signal powers of said PON burst frames.   
     
     
         7 . The node of  claim 6 , wherein said adjuster further comprises a micro-mechanical optical attenuator, and further wherein a scheduler adjusts said micro-mechanical optical attenuator based upon a known strength of a next to be received optical signal from said plurality of optical signals. 
     
     
         8 . The node of  claim 6 , wherein said adjuster further comprises a parametric amplification device with a variable pump laser, wherein said scheduler adjusts said parametric amplification with said variable pump laser based upon a known strength of a next to be received optical signal from said plurality of optical signals. 
     
     
         9 . The node of  claim 6 , wherein said node is disposed at a location other than at an optical line termination or a coupler/splitter in an optical communication system. 
     
     
         10 . A node for optical communications comprising:
 an optical line termination for receiving a plurality of optical signals from a plurality of upstream locations at an optical power equalizer within said optical line termination;   an optical equalizer for equalizing optical powers associated with said plurality of optical signals from said plurality of upstream locations, said optical equalizer including:
 at least one tapped coupler for splitting off a portion of each of said plurality of optical signals; and 
 at least one sensor for measuring an amplitude of each said portion of said plurality of optical signals; 
 wherein each of said plurality of optical signals is adapted based on a corresponding, measured amplitude by either amplifying or attenuating each of said plurality of optical signals; and said equalized signals are transmitted to a receiving unit within said optical line termination. 
   
     
     
         11 . The method of  claim 5 , wherein the amplitude for each said portion of said plurality of optical signals is measured via a PIN diode. 
     
     
         12 . The method of  claim 5 , wherein either amplifying or attenuating each of said plurality of optical signals to generate equalized signals comprises applying a gain to at least one of the plurality of optical signals. 
     
     
         13 . The method of  claim 5 , wherein either amplifying or attenuating each of said plurality of optical signals to generate equalized signals without applying a gain to any of the plurality of optical signals. 
     
     
         14 . The node of  claim 10 , wherein the at least one sensor for measuring an amplitude of each said portion of said plurality of optical signals comprises a PIN diode for measuring an amplitude of each said portion of said plurality of optical signals. 
     
     
         15 . The node of  claim 10 , wherein the node further comprises an optical modulator with power monitor configured to adapt said plurality of optical signals based on a corresponding, measured amplitude by either amplifying or attenuating each of said plurality of optical signals. 
     
     
         16 . The node of  claim 10 , wherein the node further comprises a gain saturated semiconductor optical amplifier configured to adapt said plurality of optical signals based on a corresponding, measured amplitude by either amplifying or attenuating each of said plurality of optical signals.