Bidirectional optical communications having quick data recovery without first establishing timing and phase lock

Abstract

A method of transmitting and rapidly recovering a burst of data without first having to establish a timing or phase lock. The signals are transmitted as modified Manchester coded signals having pulse transitions at a clocking pulse rate which is a multiple of the clocking pulse rate at which the signals are originally generated, and wherein the MOOSE coded signal is modified by ON-OFF keying.

1 . A distribution terminal, comprising: 
 a coding unit operable to receive a first coded data stream, the coding unit operable to convert the first coded data stream into a second coded data stream;    a keying device operable to modify the second coded data stream into a modified second coded data stream; and    a laser source operable to modulate an optical signal with the modified second coded data stream.    
     
     
         2 . The distribution terminal of  claim 1 , wherein the first coded data stream is a NRZ coded data stream.  
     
     
         3 . The distribution terminal of  claim 1 , wherein the second coded data stream is a Manchester coded data stream.  
     
     
         4 . The distribution terminal of  claim 1 , further comprising: 
 a clock multiplier operable to provide a clock signal to the coding unit and the keying device.    
     
     
         5 . The distribution terminal of  claim 4 , wherein the clock signal provided to the coding unit is twice a clock rate associated with the first coded data stream.  
     
     
         6 . The distribution terminal of  claim 4 , wherein the clock signal provided to the keying device to modify the second coded data stream is a multiple of a clock rate associated with the first coded data stream.  
     
     
         7 . The distribution terminal of  claim 1 , wherein the keying device provides a reference voltage having a first level for the modified second coded data stream corresponding to a first voltage level of the second coded data stream.  
     
     
         8 . The distribution terminal of  claim 6 , wherein the keying device provides reference voltages alternating between a second level and the first level for the modified second coded data stream corresponding to a second voltage level of the second coded data stream.  
     
     
         9 . The distribution terminal of  claim 1 , further comprising: 
 a bandpass filter operable to pass only a portion of the modified second coded data stream within a predetermined threshold region.    
     
     
         10 . The distribution terminal of  claim 1 , wherein modulation of the optical signal is performed without establishing a timing or phase lock.  
     
     
         11 . A method for generating an optical signal, comprising: 
 receiving a first coded data stream;    converting the first coded data stream into a second coded data stream;    modifying the second coded data stream into a modified second coded data stream;    modulating an optical signal with the modified second coded data stream.    
     
     
         12 . The method of  claim 11 , further comprising: 
 passing a portion of the modified second coded data stream falling within a predetermined threshold region.    
     
     
         13 . The method of  claim 11 , wherein modifying the second coded data stream includes: 
 providing a reference voltage having a first level corresponding to a first voltage level of the second coded data stream.    
     
     
         14 . The method of  claim 13 , wherein modifying the second coded data stream includes: 
 providing alternating reference voltages between a second level and the first level corresponding to a second voltage level of the second coded stream.    
     
     
         15 . The method of  claim 11 , wherein the first coded data stream is a NRZ coded data stream and the second coded data stream is a Manchester coded data stream.  
     
     
         16 . A system for generating an optical signal, comprising: 
 means for receiving a first coded data stream;    means for converting the first coded data stream into a second coded data stream;    means for modifying the second coded data stream into a modified second coded data stream;    means for modulating an optical signal with the modified second coded data stream.    
     
     
         17 . The system of  claim 16 , further comprising: 
 means for passing a portion of the modified second coded data stream falling within a predetermined threshold region.    
     
     
         18 . The system of  claim 16 , wherein the means for modifying the second coded data stream includes: 
 means for providing a reference voltage having a first level corresponding to a first voltage level of the second coded data stream.    
     
     
         19 . The system of  claim 18 , wherein the means for modifying the second coded data stream includes: 
 means for providing alternating reference voltages between a second level and the first level corresponding to a second voltage level of the second coded stream.    
     
     
         20 . The system of  claim 16 , wherein the first coded data stream is a NRZ coded data stream and the second coded data stream is a Manchester coded data stream.