Optical waveguide, optical waveguide module and method for forming optical waveguide

Abstract

An optical waveguide comprising a core and a clad characterized in that a desired part is heated and transited to machining strain release state, the part transited to the machining strain release state is curved with a specified bending radius and transited to machining strain state. That part of the optical waveguide is heated to a temperature within a range between the bending point and softening point and transited to machining strain state. The optical waveguide is an optical fiber having the outer diameter not shorter than 50 μm. The optical waveguide has the outer diameter not shorter than ten times of the mode field diameter of the optical waveguide. The optical waveguide has a bending radius of 5.0 mm or less and difference equivalent of refractive index &Dgr; 1 between the core and clad falls within a range of 0.8-3.5%.

1 . An optical waveguide having a core and a clad, wherein a specified portion is heated to move into a process distortion free state, said portion moved into the process distortion free state is bent in a curved line at a specified bend, radius under the process distortion state.  
   
   
       2 . An optical waveguide according to  claim 1 , wherein said portion of said optical waveguide is heated to a temperature within a range of not less than a folding point to not more than softening point to move the process distortion state.  
   
   
       3 . An optical waveguide according to  claim 1  or  2 , wherein said optical waveguide is an optical fiber having an outer diameter of 50 μm.  
   
   
       4 . An optical waveguide according to  claim 1  or  2 , wherein an outer diameter of said optical waveguide is not less than 10 times of mode field diameter of said optical waveguide.  
   
   
       5 . An optical waveguide according to any one of  claims 1  to  4 , said bend radius is not more than 5.0 mm.  
   
   
       6 . An optical waveguide according to any one of  claims 1  to  5 , a core/clad equivalent refractive index difference Δ 1  of said optical waveguide is within a range from not less than 0.8% to not more than 3.5%.  
   
   
       7 . An optical waveguide module comprising multiple optical waveguides described in any one of  claims 1  to  6 , wherein said multiple optical waveguides are arrayed and at least some part of said optical waveguides is fixed to a member comprising a positioning mechanism.  
   
   
       8 . An optical waveguide module comprising a optical waveguide described in any one of  claims 1  to  6 , wherein to at least one end of said optical waveguide, an optical waveguide having an core/clad equivalent refractive index difference Δ 2  of not less than 0.2% is fusion bonded, the fusion bonded portion is heated to reduce mismatch of said core/clad equivalent refractive index differences Δ and mismatch of mode field diameters.  
   
   
       9 . An optical waveguide module comprising an optical wave guides described in any one of  claims 1  to  6 , wherein said optical waveguide is fixed on a sheet while being wired on the sheet.  
   
   
       10 . An optical waveguide module comprising an optical wave guides described in any one of  claims 1  to  6 , wherein said optical waveguide is fixed between at least two sheets while being wired therebetween.  
   
   
       11 . An optical waveguide module according to  claim 9  or  10 , wherein multiple optical waveguides are provided and fixed while being wired.  
   
   
       12 . An optical waveguide module according to any one of claims  9  to  11 , wherein a material of said sheet has flexibility.  
   
   
       13 . A method of forming an optical waveguide comprising the steps of: 
 heating a specified portion of an optical waveguide;    moving said portion of said optical waveguide into a process distortion free state;    bending said portion moved into the process distortion free state at a specified bend radius; and    moving said portion of said optical waveguide into a process distortion state while being bent at the specified bend radius.