Optical add/drop device

Abstract

Disclosed herein is an optical add/drop device including an optical demultiplexer for separating WDM signal light into n optical signals where n is an integer not less than 2, n first optical switches to which the n optical signals output from the optical demultiplexer are supplied, respectively, a second optical switch for adding provided on the input side of the first optical switches, a third optical switch for dropping provided on the output side of the first optical switches, n regenerators for wavelength converting the optical signals passed through the first optical switches, and an optical multiplexer for wavelength division multiplexing the wavelength-converted optical signals. A transmission distance between nodes can be increased by using this device.

What is claimed is:  
     
         1 . An optical add/drop device comprising: 
 an optical demultiplexer for separating WDM signal light into n (n is an integer satisfying 1<n) optical signals having different wavelengths, said WDM signal light being obtained by wavelength division multiplexing said n optical signals;    n first optical switches each having first and second input ports and first and second output ports, said n optical signals output from said optical demultiplexer being supplied to said first input ports of said n first optical switches, respectively;    a second optical switch having k (k is a natural number) input ports and n output ports, an optical signal to be added being supplied to at least one of said k input ports of said second optical switch, said n output ports of said second optical switch being connected to said second input ports of said n first optical switches, respectively;    n regenerators connected to said first output ports of said n first optical switches, respectively;    an optical multiplexer for wavelength division multiplexing optical signals output from said n regenerators; and    a third optical switch having n input ports and k output ports, said n input ports of said third optical switch being connected to said second output ports of said n first optical switches, respectively, an optical signal to be dropped being output from at least one of said k output ports of said third optical switch.    
     
     
         2 . An optical add/drop device according to  claim 1 , further comprising k wavelength converters connected to said k output ports of said third optical switch, respectively.  
     
     
         3 . An optical add/drop device according to  claim 1 , further comprising n wavelength converters connected between said n input ports of said third optical switch and said second output ports of said n first optical switches, respectively.  
     
     
         4 . An optical add/drop device according to  claim 1 , further comprising n wavelength converters connected between said optical demultiplexer and said first input ports of said n first optical switches, respectively.  
     
     
         5 . An optical add/drop device according to  claim 1 , wherein: 
 said second optical switch further has r (r is a natural number) input ports;    said third optical switch further has r output ports; and    said optical add/drop device further comprises r links for connecting said r input ports of said second optical switch and said r output ports of said third optical switch.    
     
     
         6 . An optical add/drop device comprising: 
 an optical demultiplexer for separating WDM signal light into n (n is an integer satisfying 1<n) optical signals having different wavelengths, said WDM signal light being obtained by wavelength division multiplexing said n optical signals;    n optical switches each having first and second input ports and first and second output ports, said n optical signals output from said optical demultiplexer being supplied to said first input ports of said n optical switches, respectively;    a first electrical switch having k (k is a natural number) input ports, s (s is a natural number) input ports, and n output ports;    k first opto/electrical converters connected to said k input ports of said first electrical switch, respectively;    n first electro/optical converters for connecting said n output ports of said first electrical switch and said second input ports of said n optical switches, respectively;    an optical multiplexer for wavelength division multiplexing optical signals output from said first output ports of said n optical switches;    a second electrical switch having n input ports, k output ports, and s output ports;    n second opto/electrical converters for connecting said n input ports of said second electrical switch and said second output ports of said n optical switches, respectively;    k second electro/optical converters connected to said k output ports of said second electrical switch, respectively; and    s electrical links for connecting said s input ports of said first electrical switch and said s output ports of said second electrical switch, respectively.    
     
     
         7 . An optical add/drop device comprising: 
 an optical demultiplexer for separating WDM signal light into n (n is an integer satisfying 1<n) optical signals having different wavelengths, said WDM signal light being obtained by wavelength division multiplexing said n optical signals;    n optical switches each having first and second input ports and first and second output ports, said n optical signals output from said optical demultiplexer being supplied to said first input ports of said n optical switches, respectively;    a first electrical switch having k (k is a natural number) input ports, s (s is a natural number) input ports, and n output ports;    (k+s) first opto/electrical converters connected to said (k+s) input ports of said first electrical switch, respectively;    n first electro/optical converters for connecting said n output ports of said first electrical switch and said second input ports of said n optical switches, respectively;    an optical multiplexer for wavelength division multiplexing optical signals output from said first output ports of said n optical switches;    a second electrical switch having n input ports, k output ports, and s output ports;    n second opto/electrical converters for connecting said n input ports of said second electrical switch and said second output ports of said n optical switches, respectively;    (k+s) second electro/optical converters connected to said (k+s) output ports of said second electrical switch, respectively; and    s optical links for connecting said first opto/electrical converters respectively corresponding to said s input ports of said first electrical switch and said second electro/optical converters respectively corresponding to said s output ports of said second electrical switch, respectively.    
     
     
         8 . An optical add/drop device adapted to first and second optical paths, comprising: 
 first and second optical add/drop units connected to said first and second optical paths, respectively;    an add switch for selectively adding an optical signal to any one of said first and second optical add/drop units; and    a drop switch for selectively dropping an optical signal from any one of said first and second optical add/drop units;    each of said first and second optical add/drop units comprising: 
 an optical demultiplexer for separating WDM signal light into n (n is an integer satisfying 1<n) optical signals having different wavelengths, said WDM signal light being obtained by wavelength division multiplexing said n optical signals;  
 n optical switches each having first and second input ports and first and second output ports, said n optical signals output from said optical demultiplexer being supplied to said first input ports of said n optical switches, respectively;  
 n regenerators connected to said first output ports of said n optical switches, respectively; and  
 an optical multiplexer for wavelength division multiplexing optical signals output from said n regenerators;  
 said add switch being connected to said second input ports of said n optical switches;  
 said drop switch being connected to said second output ports of said n optical switches.