Device for adding and dropping optical signals

Abstract

A method for adding at least one added signal to, and dropping at least one dropped signal from at least one of a first transmission path and a second transmission path, the method including (i) creating a first series of signals and a second series of signals, the signals having distinct wavelengths, the first series and the second series being mutually staggered in wavelength, (ii) transmitting the first series to the first transmission path and the second series to the second transmission path, and, (iii) providing a wavelength selective switch along at least one of the first transmission path and the second transmission path, the wavelength selective switch for adding the at least one added signal and dropping the at least one dropped signal.

What is claimed is:  
     
         1 . A method for adding at least one added signal to, and dropping at least one dropped signal from at least one of a first transmission path and a second transmission path, the method comprising: 
 creating a first series of signals and a second series of signals, the signals having distinct wavelengths, the first series and the second series being mutually staggered in wavelength,    transmitting the first series to the first transmission path and the second series to the second transmission path, and,    providing a wavelength selective switch along at least one of the first transmission path and the second transmission path, the wavelength selective switch for adding the at least one added signal and dropping the at least one dropped signal.    
     
     
         2 . A method according to  claim 1 , further comprising combining the signals from the first transmission path and the second transmission path.  
     
     
         3 . A method according to  claim 1 , where creating includes using a spectral selection circuit.  
     
     
         4 . A method according to  claim 1 , where creating includes using a divider to divide said signals into the first series and the second series.  
     
     
         5 . A method according to  claim 1 , where creating includes using an optical circulator and a selective reflection circuit.  
     
     
         6 . A method according to  claim 1 , where creating includes using an optical circulator and at least one Bragg grating filter.  
     
     
         7 . A method according to  claim 1 , where the wavelengths of the first series and the wavelengths of the second series are separated by a value lower than the spectral resolution of the wavelength selective switch.  
     
     
         8 . A method according to  claim 1 , where the at least one signal is an optical signal.  
     
     
         9 . A method according to  claim 1 , where the first transmission path and the second transmission path include a fiber optic line.  
     
     
         10 . A method according to  claim 1 , where the wavelength selective switch is an acousto-optical wavelength selective switch.  
     
     
         11 . A method for dropping at least one dropped signal from at least one of a first transmission path and a second transmission path, the method comprising: 
 creating a first series of signals and a second series of signals, the signals having distinct wavelengths, the first series and the second series being mutually staggered in wavelength,    transmitting the first series to the first transmission path and the second series to the second transmission path, and,    providing a wavelength selective switch along at least one of the first transmission path and the second transmission path, the wavelength selective switch for dropping the at least one dropped signal from at least one of the first series and the second series.    
     
     
         12 . A method according to  claim 11 , further comprising combining the signals from the first transmission path and the second transmission path.  
     
     
         13 . A method according to  claim 11 , where creating includes using a spectral selection circuit.  
     
     
         14 . A method according to  claim 11 , where creating includes using a divider to divide said signals into the first series and the second series.  
     
     
         15 . A method according to  claim 11 , where creating includes using an optical circulator and a selective reflection circuit.  
     
     
         16 . A method for adding at least one added signal from at least one of a first transmission path and a second transmission path, the method comprising: 
 creating a first series of signals and a second series of signals, the signals having distinct wavelengths, the first series and the second series being mutually staggered in wavelength,    transmitting the first series to the first transmission path and the second series to the second transmission path, and,    providing a wavelength selective switch along at least one of the first transmission path and the second transmission path, the wavelength selective switch for adding the at least one added signal from at least one of the first series and the second series.    
     
     
         17 . A method according to  claim 16 , further comprising combining the signals from the first transmission path and the second transmission path.  
     
     
         18 . A method according to  claim 16 , where creating includes using a spectral selection circuit.  
     
     
         19 . A method according to  claim 16 , where creating includes using a divider to divide said signals into the first series and the second series.  
     
     
         20 . A method according to  claim 16 , where creating includes using an optical circulator and a selective reflection circuit.