Method of preparing a planar optical waveguide assembly

Abstract

A method of preparing a planar optical waveguide assembly, comprising the steps of: (i) applying a silicone composition to a surface of a substrate to form a silicone film; (ii) exposing at least one selected region of the silicone film to radiation having a wavelength of from 150 to 800 nm to produce a partially exposed film having at least one exposed region and at least one non-exposed region; (iii) removing the non-exposed region of the partially exposed film with a developing solvent to form a patterned film; and (iv) heating the patterned film for an amount of time sufficient to form at least one silicone core having a refractive index of from 1.3 to 1.7 at 23° C. for light having a wavelength of 589 nm; wherein the substrate has a refractive index less than the refractive index of the silicone core.

1 . A method of preparing a planar optical waveguide assembly, comprising the steps of: 
 (i) applying a silicone composition to a surface of a substrate to form a silicone film, wherein the silicone composition comprises: 
 (A) an organopolysiloxane containing an average of at least two silicon-bonded alkenyl groups per molecule,  
 (B) an organosilicon compound containing an average of at least two silicon-bonded hydrogen atoms per molecule in a concentration sufficient to cure the composition, and  
 (C) a catalytic amount of a photoactivated hydrosilylation catalyst;  
   (ii) exposing at least one selected region of the silicone film to radiation having a wavelength of from 150 to 800 nm to produce a partially exposed film having at least one exposed region and at least one non-exposed region;    (iii) removing the non-exposed region of the partially exposed film with a developing solvent to form a patterned film; and    (iv) heating the patterned film for an amount of time sufficient to form at least one silicone core having a refractive index of from 1.3 to 1.7 at 23° C. for light having a wavelength of 589 nm; wherein the substrate has a refractive index less than the refractive index of the silicone core.    
   
   
       2 . The method according to  claim 1 , wherein the organopolysiloxane is an organopolysiloxane resin.  
   
   
       3 . The method according to  claim 2 , wherein the organopolysiloxane resin consists essentially of R 2   3 SiO 1/2  units and R 1 SiO 3/2  units, wherein the mole ratio of R 2   3 SiO 1/2  units to R 1 SiO 3/2  units is from 0.05 to 1.0, each R 1  is independently selected from hydrocarbyl, deuterium-substituted hydrocarbyl, and halogen-substituted hydrocarbyl, all free of aliphatic unsaturation, and R 2  is R 1  or alkenyl.  
   
   
       4 . The method according to  claim 3 , wherein the organopolysiloxane resin consists essentially of PhSiO 3/2  units and CH2=CH(CH 3 ) 2 SiO 1/2  units.  
   
   
       5 . The method according to  claim 1 , wherein the photoactivated hydrosilylation catalyst is a platinum(II) β-diketonate.  
   
   
       6 . The method according to  claim 5 , wherein the platinum (II) β-diketonate is platinum(II) bis(2,4-pentanedioate).  
   
   
       7 . The method according to  claim 1 , wherein the substrate is silicon or silicon dioxide.  
   
   
       8 . The method according to  claim 1 , wherein the silicone core has a thickness of from 1 to 100 μm.  
   
   
       9 . The method according to  claim 1 , further comprising (v) covering the substrate and the silicone core with a curable polymer composition to form a polymer film and (vi) curing the polymer film to form a clad layer, wherein the clad layer has a refractive index less than the refractive index of the silicone core.  
   
   
       10 . The method according to  claim 9 , wherein the curable polymer composition is a curable silicone composition.  
   
   
       11 . The method according to  claim 10 , wherein the curable silicone composition is the silicone composition in step (i).  
   
   
       12 . The method according to  claim 9 , wherein the clad layer has a thickness of from 5 to 200 μm.  
   
   
       13 . A method of preparing a planar optical waveguide assembly, comprising the steps of: 
 (i) applying a silicone composition to a surface of a substrate to form a silicone film, wherein the silicone composition comprises: 
 (A) an organopolysiloxane containing an average of at least two silicon-bonded alkenyl groups per molecule,  
 (B) an organosilicon compound containing an average of at least two silicon-bonded hydrogen atoms per molecule in a concentration sufficient to cure the composition, and  
 (C) a catalytic amount of a photoactivated hydrosilylation catalyst;  
   (ii) exposing at least one selected region of the silicone film to radiation having a wavelength of from 150 to 800 nm to produce a partially exposed film having at least one exposed region and at least one non-exposed region;    (iii) heating the partially exposed film for an amount of time such that the exposed region is substantially insoluble in a developing solvent and the non-exposed region is soluble in the developing solvent;    (iv) removing the non-exposed region of the heated film with the developing solvent to form a patterned film; and    (v) heating the patterned film for an amount of time sufficient to form at least one silicone core having a refractive index of from 1.3 to 1.7 at 23° C. for light having a wavelength of 589 nm; wherein the substrate has a refractive index less than the refractive index of the silicone core.    
   
   
       14 . The method according to  claim 13 , wherein the organopolysiloxane is an organopolysiloxane resin.  
   
   
       15 . The method according to  claim 14 , wherein the organopolysiloxane resin consists essentially of R 2   3 SiO 1/2  units and R 1 SiO 3/2  units, wherein the mole ratio of R 2   3 SiO 1/2  units to R 1 SiO 3/2  units is from 0.05 to 1.0, each R 1  is independently selected from hydrocarbyl, deuterium-substituted hydrocarbyl, and halogen-substituted hydrocarbyl, all free of aliphatic unsaturation, and R 2  is R 1  or alkenyl.  
   
   
       16 . The method according to  claim 15 , wherein the organopolysiloxane resin consists essentially of PhSiO 3/2  units and CH2=CH(CH 3 ) 2 SiO 1/2  units.  
   
   
       17 . The method according to  claim 13 , wherein the photoactivated hydrosilylation catalyst is a platinum(II) β-diketonate.  
   
   
       18 . The method according to  claim 17 , wherein the platinum (II) β-diketonate is platinum(II) bis(2,4-pentanedioate).  
   
   
       19 . The method according to  claim 13 , wherein the substrate is silicon or silicon dioxide.  
   
   
       20 . The method according to  claim 13 , wherein the partially exposed film is heated at a temperature of from 50 to 250° C. for 0.1 to 10 min.  
   
   
       21 . The method according to  claim 13 , wherein the silicone core has a thickness of from 1 to 100 μm.  
   
   
       22 . The method according to  claim 13 , further comprising further comprising (vi) covering the substrate and the silicone core with a curable polymer composition to form a polymer film and (vii) curing the polymer film to form a clad layer, wherein the clad layer has a refractive index less than the refractive index of the silicone core.  
   
   
       23 . The method according to  claim 22 , wherein the curable polymer composition is a curable silicone composition.  
   
   
       24 . The method according to  claim 23 , wherein the curable silicone composition is the silicone composition in step (i).  
   
   
       25 . The method according to  claim 22 , wherein the clad layer has a thickness of from 5 to 200 μm.