Fiber for compensation of the cumulative chromatic dispersion in a fibre with negative chromatic dispersion

Abstract

The fibre is adapted to compensation of the chromatic dispersion and chromatic dispersion slope of an optical fibre with negative chromatic dispersion. It has, in a propagation mode other than the fundamental mode, a positive chromatic dispersion and a negative chromatic dispersion slope. The fibre can be used in compensation dispersion modules or as line fibre, in transmission systems using line fibre with negative chromatic dispersion.

1 - 9 . (canceled)  
     
     
         10 . A transmission system, having: 
 a transmitter of optical signals in a predetermined wavelength range;    a section of a first optical fibre ( 6   i ,  24   i ) which is single-mode in the wavelength range and having in the wavelength range a negative chromatic dispersion and a positive chromatic dispersion slope;    a mode transformer ( 12   i , 28   i );    a section ( 14   i ,  26   i ) of a second optical fibre in which the transformed signals propagate in a higher order mode, the second optical fibre having in the wavelength range a positive chromatic dispersion and a negative chromatic dispersion slope.    
     
     
         11 . The system according to  claim 10 , characterised in that the higher order mode has a circular symmetry in the second fibre.  
     
     
         12 . The system according to  claim 10 , characterised in that the second fibre has, in the higher order propagation mode and in the wavelength range, an effective area greater then or equal to 50 μm 2 .  
     
     
         13 . The system according to  claim 10 , characterised in that the wavelength range contains the wavelength 1550 nm.  
     
     
         14 . The system according to  claim 10 , characterised in that the second fibre has, in the wavelength range, a chromatic dispersion greater than or equal to 4 ps/(nm·km), preferably greater than or equal to 10 ps/(nm·km).  
     
     
         15 . The system according to  claim 10 , characterised in that the second fibre has, in the wavelength range, a ratio of chromatic dispersion to chromatic dispersion slope between −90 and −20 nm.  
     
     
         16 . The system according to  claim 10 , characterised in that it furthermore comprises a third fibre having, in the fundamental mode and in the wavelength range: 
 a positive chromatic dispersion;    a positive chromatic dispersion slope.    
     
     
         17 . The system according to  claim 16 , characterised in that the second fibre has a ratio of chromatic dispersion to chromatic dispersion slope greater than or equal to −1 nm.  
     
     
         18 . The system according to  claim 16 , characterised in that the second fibre has a chromatic dispersion slope less than or equal to −0.1 ps/(nm 2 ·km), preferably less than or equal to −0.5 ps/(nm 2 ·km).  
     
     
         19 . The system according to  claim 10 , characterised in that the first fibre is an NZ-DSF− fibre.  
     
     
         20 . The system according to  claim 10 , characterised in that the absolute value of the cumulative chromatic dispersion in the wavelength range remains less than 50 ps/nm and preferably less than 25 ps/nm.