Dispersion compensation apparatus including a fixed dispersion compensator for coarse compensation and a variable dispersion compensator for fine compensation

Abstract

An apparatus which compensates for dispersion in an optical transmission line. The apparatus includes a fixed dispersion compensator and a variable dispersion compensator. The fixed dispersion compensator has a fixed dispersion amount and coarsely compensates for the dispersion in the transmission line. The variable dispersion compensator has a variable dispersion amount and finely compensates for the dispersion in the transmission line. The fixed and variable dispersion compensators can be located at many positions. For example, one may be in a transmitter and the other may be in a receiver. Both may be in the transmitter and/or the receiver. One may be in either the transmitter or the receiver, with the other in an optical repeater positioned along the transmission line.

1 . An apparatus comprising: 
 a receiver section including: 
 a fixed dispersion compensator providing a fixed dispersion compensation to an optical signal,  
 a variable dispersion compensator providing a finely variable dispersion compensation to the optical signal, and  
 a receiver receiving the optical signal which can be finely compensated by the fixed dispersion compensator and the variable dispersion compensator.  
   
   
   
       2 . An apparatus as in  claim 1 , further comprising: 
 a measuring unit measuring a transmission characteristic of the optical signal compensated by the variable dispersion compensator and the fixed dispersion compensator and transmitted through a transmission line, wherein the variable dispersion compensation of the variable dispersion compensator is controlled in accordance with the transmission characteristic measured by the measuring unit.    
   
   
       3 . An apparatus comprising: 
 a transmitter section including: 
 a transmitter transmitting an optical signal,  
 a fixed dispersion compensator providing a fixed dispersion compensation to the optical signal, and  
 a variable dispersion compensator providing a finely variable dispersion compensation to the optical signal,  
 wherein the optical signal form the transmitter section can be provided with compensation by the fixed dispersion compensator and the variable dispersion compensator.  
   
   
   
       4 . An apparatus as in  claim 3 , further comprising: 
 a measuring unit measuring a transmission characteristic of the optical signal compensated by the variable dispersion compensator and the fixed dispersion compensator and transmitted through a transmission line, wherein the variable dispersion compensation of the variable dispersion compensator is controlled in accordance with the transmission characteristic measured by the measuring unit.    
   
   
       5 . An apparatus comprising: 
 a transmitter transmitting an optical signal;    a repeater repeating the optical signal from the transmitter; and    a receiver section that includes:    a first fixed dispersion compensator providing a fixed dispersion compensation to an optical signal;    a variable dispersion compensator providing a finely variable dispersion compensation to the optical signal; and    a receiver receiving the optical signal from the repeater, which can be finely compensated by the first fixed dispersion compensator and the variable dispersion compensator,    wherein the repeater further includes a second fixed dispersion compensator.