Dispersion compensating method and dispersion compensating apparatus

Abstract

A dispersion compensating method for carrying out automatic level control with the use of target output power and an ASE correction value corresponding to the number of wavelengths to multiplex and making output power of a wavelength multiplexed signal constant, comprising the steps of: switching into automatic gain control in which the output power of the wavelength multiplexed signal is made constant, to carry out increase/decrease of the wavelengths to multiplex; varying a dispersion compensating amount based on the increase/decrease of the wavelengths by the automatic gain control; calculating an ASE variation amount due to the change in the dispersion compensating amount; and reflecting the ASE variation amount on the ASE correction value and switching into the automatic level control.

1 . A dispersion compensating method for varying output power according to the number of wavelengths to multiplex, comprising the step of: 
 varying a dispersion compensating amount to compensate variation in the output power of each wavelength.    
   
   
       2 . A dispersion compensating method for carrying out automatic level control with the use of target output power and an ASE correction value corresponding to the number of wavelengths to multiplex and making output power of a wavelength multiplexed signal constant, comprising the steps of: 
 switching into automatic gain control in which the output power of the wavelength multiplexed signal is made constant, to carry out increase/decrease of the wavelengths to multiplex;    varying a dispersion compensating amount based on the increase/decrease of the wavelengths in the automatic gain control;    calculating an ASE variation amount due to the change in the dispersion compensating amount; and    reflecting the ASE variation amount on the ASE correction value and switching into the automatic level control.    
   
   
       3 . A dispersion compensating method for carrying out automatic level control with the use of target output power and an ASE correction value corresponding to the number of wavelengths to multiplex and making output power of a wavelength multiplexed signal constant, comprising the steps of: 
 switching into automatic gain control in which the output power of the wavelength multiplexed signal is made constant, to vary the dispersion compensating amount based on increase/decrease of the wavelengths to multiplex;    calculating an ASE variation amount due to the change in the dispersion compensating amount;    carrying out increase/decrease of the number of wavelengths to multiplex in the automatic gain control; and    reflecting the ASE variation amount on the ASE correction value and switching into the automatic level control.    
   
   
       4 . A dispersion compensating apparatus for varying output power according to the number of wavelengths to multiplex, comprising: 
 a dispersion compensating amount varying part of varying a dispersion compensating amount to compensate variation in the output power of each wavelength.    
   
   
       5 . A dispersion compensating apparatus for carrying out automatic level control with the use of target output power and an ASE correction value corresponding to the number of wavelengths to multiplex and making output power of a wavelength multiplexed signal constant, comprising: 
 a wavelength increasing/decreasing part of switching into automatic gain control in which the output power of the wavelength multiplexed signal is made constant, to carry out increase/decrease of the wavelengths to multiplex;    a dispersion compensating amount varying part of varying a dispersion compensating amount based on the increase/decrease of the wavelengths in the automatic gain control;    an ASE variation amount calculating part of calculating an ASE variation amount due to the change in the dispersion compensating amount; and    an ASE variation amount reflecting part of reflecting the ASE variation amount on the ASE correction value and switching into the automatic level control.    
   
   
       6 . A dispersion compensating apparatus for carrying out automatic level control with the use of target output power and an ASE correction value corresponding to the number of wavelengths to multiplex and making output power of a wavelength multiplexed signal constant, comprising: 
 a dispersion compensating amount varying part of switching into automatic gain control in which the output power of the wavelength multiplexed signal is made constant, to vary the dispersion compensating amount based on increase/decrease of the wavelengths to multiplex;    an ASE variation amount calculating part of calculating an ASE variation amount due to the change in the dispersion compensating amount;    a wavelength increasing/decreasing part of carrying out increase/decrease of the number of wavelengths to multiplex in the automatic gain control; and    an ASE variation among reflecting part of reflecting the ASE variation amount on the ASE correction value and switching into the automatic level control.    
   
   
       7 . The dispersion compensating apparatus as claimed in  claim 5 , comprising: 
 a switching part of switching into the automatic level control for a given period after the increase/decrease of the wavelengths to multiplex made by said wavelength increasing/decreasing part, and after that, switching into the automatic gain control.    
   
   
       8 . The dispersion compensating apparatus as claimed in  claim 6 , comprising: 
 a switching part of switching into the automatic level control for a given period after the change of dispersion compensating amount based on increase/decrease of the wavelengths to multiplex made by said wavelength increasing/decreasing part, and after that, switching into the automatic gain control.    
   
   
       9 . The dispersion compensating apparatus as claimed in  claim 5 , wherein: 
 the increase/decrease of the wavelengths is carried out stepwise with a step of each wavelength or each small number of wavelengths.    
   
   
       10 . The dispersion compensating apparatus as claimed in  claim 6 , wherein: 
 the increase/decrease of the wavelengths is carried out stepwise with a step of each wavelength or each small number of wavelengths.    
   
   
       11 . The dispersion compensating apparatus as claimed in  claim 7 , wherein: 
 the increase/decrease of the wavelengths is carried out stepwise with a step of each wavelength or each small number of wavelengths.    
   
   
       12 . The dispersion compensating apparatus as claimed in  claim 8 , wherein: 
 the increase/decrease of the wavelengths is carried out stepwise with a step of each wavelength or each small number of wavelengths.