Optical multi/demultiplexer, optical multi/demultiplexing method, and optical filter

Abstract

Disclosed is an optical multi/demultiplexer, which comprises a graded index type light transmission section whose refractive index is continuously reduced in the direction from the center to the periphery thereof, a wavelength-multiplexed-light connecting section disposed at one of the axial ends of the light transmission section, and at least one monochromatic light connecting section disposed at the other axial end of the light transmission section. The wavelength-multiplexed-light connecting section and the monochromatic light connecting section are disposed relative to the light transmission section in such a positional relationship that a monochromatic light included in a wavelength multiplexed light entered from the wavelength-multiplexed-light connecting section into the one end of the light transmission section is emitted from the other end of the light transmission section at a position where the monochromatic light connecting section is disposed. The present invention can provide an optical multi/demultiplexer having a reduced number of components and allowing the number of assembling steps to be reduced while eliminating the need for complicated adjustments.

1 . An optical multiplexer comprising: 
 a graded index type light transmission section whose refractive index is continuously reduced in the direction from the center to the periphery thereof;    a wavelength-multiplexed-light connecting section disposed at one of the axial ends of said light transmission section; and    at least one monochromatic light connecting section disposed at the other axial end of said light transmission section,    wherein said wavelength-multiplexed-light connecting section and said monochromatic light connecting section are disposed relative to said light transmission section in such a positional relationship that a monochromatic light included in a wavelength multiplexed light entered from said wavelength-multiplexed-light connecting section into said one end of said light transmission section is emitted from the other end of the light transmission section at a position where said monochromatic light connecting section is disposed.    
     
     
         2 . The optical multiplexer as defined in  claim 1 , wherein said light transmission section is made of plastic.  
     
     
         3 . The optical multiplexer as defined in  claim 2 , wherein the materials of said light transmission section are different in Abbe number at 20 or more.  
     
     
         4 . The optical multiplexer as defined in either one of  claims 1  to  3 , wherein said light transmission section has an substantially cylindrical body wherein said wavelength-multiplexed-light connecting section is disposed to the radially peripheral region of said light transmission section and in parallel with the axis of said light transmission section.  
     
     
         5 . (canceled)  
     
     
         6 . The optical multiplexer as defined in either one of  claims 1  to  3 , wherein said monochromatic light connecting section is provided in a plural number.  
     
     
         7 . An optical demultiplexing method comprising: 
 entering a wavelength multiplexed light formed by multiplexing a plurality of monochromatic lights, from one of the axial ends of a graded index type light transmission section whose refractive index is continuously reduced in the direction from the center to the periphery thereof;    demultiplexing said wavelength multiplexed light into said monochromatic lights in said light transmission section; and    emitting said monochromatic lights, respectively, from different positions of the other axial end of said light transmission section.    
     
     
         8 . An optical multiplexing method comprising: 
 entering a plurality of monochromatic lights, respectively, from different positions of one of the axial ends of a graded index type light transmission section whose refractive index is continuously reduced in the direction from the center to the periphery thereof;    multiplexing said monochromatic lights into a wavelength multiplexed light in said light transmission section;    emitting said wavelength multiplexed light from the other axial end of said light transmission section.    
     
     
         9 . An optical filter comprising: 
 a graded index type light transmission section whose refractive index is continuously reduced in the direction from the center to the periphery thereof;    a wavelength-multiplexed-light connecting section disposed at one of the axial ends of said light transmission section; and    a monochromatic light connecting section disposed at the other axial end of said light transmission section.    
     
     
         10 - 12 . (canceled)  
     
     
         13 . The optical filter as defined in claims  8  or  9 , wherein said light transmission section has an substantially cylindrical body, wherein said wavelength-multiplexed-light connecting section is connected to said light transmission section in parallel with the axis of said light transmission section.  
     
     
         14 . The optical filter as defined in  claim 8 , wherein said temperature varying means includes a Peltier element.  
     
     
         15 . The optical multiplexer as defined in either one of claims  4 , wherein said monochromatic light connecting section is provided in a plural number