Wavelength multiplexing/demultiplexing unit, wavelength multiplexing/demultiplexing apparatus and wavelength multiplexing/demultiplexing method

Abstract

An optical multiplexing/demultiplexing apparatus in which a plurality of optical multiplexing/demultiplexing units which are different from one another in operating wavelength band are connected hierarchically. Each of the optical multiplexing/demultiplexing units comprises an input waveguide for receiving a wavelength multiplexed optical waves, a filter for separating the wavelength multiplexed optical wave from the input waveguide into a first optical wave in the corresponding operating wavelength band and a second optical wave in the other wavelength bands, an AWG optical multiplexer/demultiplexer for separating the first optical wave from the filter into individual optical waves each of a single wavelength, and a branch waveguide for directing the second optical waves from the filter to the input waveguide of a succeeding optical multiplexing/demultiplexing unit.

What is claimed is:  
     
         1 . An optical multiplexing/demultiplexing unit comprising: 
 a first waveguide for receiving a wavelength multiplexed optical wave;    filter means optically connected with said first waveguide for separating the wavelength multiplexed optical wave from the first waveguide into a first optical wave in a first wavelength band and a second optical wave in a second wavelength band;    means for optical-demultiplexing the first optical wave in the first wavelength band into optical waves each of a single wavelength; and    a second waveguide for directing the second optical wave in the second wavelength band to a succeeding optical means.    
     
     
         2 . The optical multiplexing/demultiplexing unit according to    claim 1   , wherein said means for optical-demultiplexing comprises a plurality of optical multiplexing/demultiplexing circuits which are different from one another in operating wavelength band.  
     
     
         3 . The optical multiplexing/demultiplexing unit according to    claim 1   , wherein said means for optical-demultiplexing is an arrayed waveguide grating circuit.  
     
     
         4 . The optical multiplexing/demultiplexing unit according to    claim 1   , wherein said filter means is one of a highpass filter type of optical multiplexer/demultiplexer, a lowpass filter type of optical multiplexer/demultiplexer, and a bandpass filter type of optical multiplexer/demultiplexer.  
     
     
         5 . An optical multiplexing/demultiplexing unit comprising: 
 a first waveguide for receiving a wavelength multiplexed optical wave;    first filter means optically connected with the first waveguide for separating the wavelength multiplexed optical wave from the first waveguide into a first optical wave in a first wavelength band and a second optical wave in a second wavelength band;    second filter means optically connected with the first filter means for separating the first optical wave in the first wavelength band from said first filter means into a third optical wave in a third wavelength band and a fourth optical wave in a fourth wavelength band;    means for optical-demultiplexing the third optical wave in the third wavelength band from said second filter means into optical waves each of a single wavelength;    a second waveguide for outputting the second optical wave in the second wavelength band from said first filter means to a succeeding optical means; and    a third waveguide for outputting the fourth optical wave in the fourth wavelength band from said second filter means to a succeeding optical means.    
     
     
         6 . The optical multiplexing/demultiplexing unit according to    claim 5   , wherein said means for optical-demultiplexing is an arrayed waveguide grating circuit.  
     
     
         7 . The optical multiplexing/demultiplexing unit according to    claim 5   , wherein each of said first and second filter means is one of a highpass filter type of optical multiplexer/demultiplexer, a lowpass filter type of optical multiplexer/demultiplexer, and a bandpass filter type of optical multiplexer/demultiplexer.  
     
     
         8 . An optical multiplexing/demultiplexing unit comprising: 
 a substrate;    a first cladding layer stacked on said substrate;    a core layer stacked on said first cladding layer;    a second cladding layer stacked on said core layer; and    said core layer including:    a first waveguide for receiving a wavelength multiplexed optical wave;    filter means optically connected with said first waveguide for separating the wavelength multiplexed optical wave from said first waveguide into a first optical wave in a first wavelength band and a second optical wave in a second wavelength band;    means for optical-demultiplexing the first optical wave in the first wavelength band into optical waves each of a single wavelength; and    a second waveguide for directing the second optical wave in the second wavelength band to a succeeding optical means.    
     
     
         9 . An optical multiplexing/demultiplexing apparatus comprising: 
 a plurality of optical multiplexing/demultiplexing units which are different from one another in operating wavelength band are connected hierarchically, wherein each of the optical multiplexing/demultiplexing units is according to one of said optical multiplexing/demultiplexing units.    
     
     
         10 . The optical multiplexing/demultiplexing apparatus according to    claim 9   , wherein said means for optical-demultiplexing is an arrayed waveguide grating circuit.  
     
     
         11 . The optical multiplexing/demultiplexing apparatus according to    claim 9   , wherein said first filter means is one of a highpass filter type of optical multiplexer/demultiplexer, a lowpass filter type of optical multiplexer/demultiplexer, and a bandpass filter type of optical multiplexer/demultiplexer.  
     
     
         12 . The optical multiplexing/demultiplexing apparatus according to    claim 9   , wherein said optical multiplexing/demultiplexing units are connected in the order of operating wavelength band beginning with the shortest wavelength band.  
     
     
         13 . The optical multiplexing/demultiplexing apparatus according to    claim 9   , wherein said optical multiplexing/demultiplexing units are connected in the order of operating wavelength band beginning with the longest wavelength band.  
     
     
         14 . The optical multiplexing/demultiplexing apparatus according to    claim 9   , wherein said means for optical-demultiplexing comprises a plurality of optical multiplexing/demultiplexing circuits which are different from one another in operating wavelength band.  
     
     
         15 . An optical multiplexing/de multiplexing apparatus in which a plurality of optical multiplexing/demultiplexing units which are different from one another in operating wavelength band are connected hierarchically, each of said optical multiplexing/de multiplexing units comprising: 
 a first waveguide for receiving a wavelength multiplexed optical wave;    filter means optically connected with the first waveguide for separating the wavelength multiplexed optical wave from the first waveguide into a first optical wave having the corresponding operating wavelength band and a second optical wave having the other wavelength bands;    means for optical-demultiplexing the first optical wave from said filter means into optical waves each of a single wavelength; and    a second waveguide for directing the second optical wave from said filter means to a first waveguide of a succeeding optical multiplexing/demultiplexing unit.    
     
     
         16 . A method of demultiplexing an incident wavelength multiplexed optical wave in steps into different wavelength bands comprising: 
 a first step of separating the wavelength multiplexed optical wave into a first optical wave in a first wavelength band and a second optical wave in a second wavelength band and then demultiplexing the first optical wave in the first wavelength band into individual optical waves each of a single wavelength; and    a second step, which is repeated subsequent to the first step until all optical waves of different wavelengths contained in the wavelength multiplexed optical wave are separated, of separating the second optical wave in the second wavelength band into a wavelength multiplexed optical wave in a specific wavelength band and a optical wave in the remaining wavelength band and then demultiplexing the wavelength multiplexed optical wave in the specific wavelength band into individual optical waves.    
     
     
         17 . A method of demultiplexing an incident wavelength multiplexed optical wave into different wavelength bands comprising: 
 a first step of separating the wavelength multiplexed optical wave into a first optical wave in a first wavelength band and a second optical wave in a second wavelength band by a first filter means, and then outputting the first optical wave to succeeding optical means and the second optical wave to a second filter means;    a second step of separating the first optical wave from said first filter means into a third optical wave in a third wavelength band and a fourth optical wave in a fourth wavelength band by a second filter means, and then outputting the third optical wave to multiplexing/demultiplexing means and the fourth optical wave to succeeding optical means; and    a third step of optical-demultiplexing the third optical wave into optical waves each of a single wavelength from said multiplexing/demultiplexing means.