Method of forming optical waveguide circuit path

• US 3,873,339 A
• Filed: 02/01/1974
• Issued: 03/25/1975
• Est. Priority Date: 03/30/1972
• Status: Expired due to Term

• Current Assignee: Marshall C. Hudson
• Original Assignee: Marshall C. Hudson
• Inventors: Hudson, Marshall C.
• Primary Examiner(s): Martin, William D.
• Assistant Examiner(s): Beck, Shrive P.
• Application Number:
  US05/438,527
• Time in Patent Office: 417 Days
• Field of Search: 117/23,7B,7S,40,93.3,124A,125,17 350/96WG
• US Class Current: 427/452
• CPC Class Codes: C03B 19/14 by gas- or vapour- phase reaction processes
• CPC Class Codes: C03B 37/014 made entirely or partially by chemical means , e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD] C03C17/02 takes precedence
• CPC Class Codes: C03C 17/02 with glass C03C17/34, C03C17/44 take precedence
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 23/0025 by a laser beam
• CPC Class Codes: G02B 6/13 Integrated optical circuits characterised by the manufacturing method
• CPC Class Codes: Y10S 430/146 Laser beam

Abstract

A method of producing a planar optical waveguide circuit path by applying to at least a portion of a smooth surface of a glass substrate having a predetermined desired index of refraction a first coating of glass particles having an index of refraction greater than that of the glass substrate. A beam of laser light is caused to impinge upon the first coating and is caused to move thereacross in a predetermined manner to form a narrow path of fused glass on the surface of the substrate. After the remaining unfused glass particles are removed, a film of glass having an index of refraction less than that of the fused glass path may be applied over that path and at least a portion of the exposed surface of the substrate adjacent thereto.

Claims

1. A METHOD OF FORMING A PLANAR OPTICAL WAVE-GUIDE COMPRISING THE STEPS OF PROVIDING A GLASS SUBSTRATE HAVING A PREDETERMINED DESIRED INDEX OF REFRACTION, APPLYING A FIRST COATING OF GLASS PARTICLES HAVING AN INDEX OF REFRACTION GREATER THAN THAT OF SAID GLASS SUBSTRATE TO AT LEAST A PORTION OF ONE SURFACE OF SAID SUBSTRATE, DIRECTING A BEAM OF LASER LIGHT ONTO SAID FIRST COATING TO FUSE THOSE GLASS PARTICLES UPON WHICH SAID BEAM IMPINGES DUE TO ABSORPTION OF LIGHT ENERGY THEREBY, MOVING SAID SUBSTRATE RELATIVE TO SAID BEAM TO FORM A PATH OF FUSED GLASS, REMOVING FROM SAID SUBSTRATE THE UNFUSED PORTION OF SAID FIRST COATING, AND DISPOSING ON THE ENTIRE EXPOSED SURFACE OF SAID PATH OF FUSED GLASS AND AT LEAST A PORTION OF THE EXPOSED SURFACE OF SAID SUBSTRATE WHICH IS ADJACENT THERETO A CONTINUOUS FILM OF NON-PARTICULATE GLASS HAVING A REFRACTIVE INDEX LESS THAN THAT OF SAID PATH OF FUSED GLASS.

2. The method of claim 1 wherein said first coating of glass particles is formed by depositing a layer of glass soot on at least a portion of one flat surface of said substrate by flame hydrolysis.

3. The method of claim 1 wherein said glass film is formed by the steps of depositing a second coating of glass particles over said path of fused glass and at least a portion of the exposed surface of said substrate adjacent thereto, and heating said second coating to fuse the glass particles thereof.

4. The method of claim 3 wherein said second coating is formed by depositing by flame hydrolysis a coating of glass soot over said path of fused glass and at least a portion of the exposed surface of said substrate adjacent thereto.

5. The method of claim 1 wherein said first coating of glass particles is formed by the step of depositing a first coating of doped silica soot over at least a portion of one flat surface of said substrate by flame hydrolysis, and wherein said glass film is formed by the step of depositing by the flame hydrolysis process a second coating of silica soot over said path of fused glass and at least a portion of the exposed surface of said substrate adjacent thereto and heating the structure so formed until said second coating of soot fuses and forms said film of glass.

6. The method of claim 5 wherein said first coating of soot is silica doped with at least one material selected from the group consisting of titanium oxide, tantalum oxide, tin oxide, niobium oxide, zirconium oxide, aluminum oxide, lanthanum oxide and germanium oxide.

7. The method of claim 5 wherein said first coating of soot is silica doped with not more than 20 percent by weight titanium oxide.

8. The method of claim 1 wherein said film of glass is applied by radio frequency sputtering.

9. The method of claim 1 wherein said film of glass is applied by chemical vapor deposition.

10. The method of claim 1 wherein said film of glass is formed by applying a glass frit and thereafter fused said frit.

11. A method of forming a planar optical waveguide comprising the steps of providing a substantially flat glass substrate having a predetermined desired index of refraction, depositing over at least a portion of one flat surface of said substrate by flame hydrolysis a first coating of doped silica soot having an index of refraction greater than that of said substrate, directing a beam of laser light onto said first coating to fuse that soot upon which said beam impinges due to absorption of light energy thereby, moving said substrate relative to said beam to form a path of doped fused silica, removing from said substrate the unfused portion of said first coating, depositing by flame hydrolysis a second coating of silica soot over said path of doped fused silica and at least a portion of the exposed surface of said substrate adjacent thereto and, heating the structure so formed to form from said second coating a film of fused silica.

12. The method of claim 11 wherein said substrate consists of Silica.

13. The method of claim 12 wherein said first coating of soot is silica doped with at least one material selected from the group consisting of titanium oxide, tantalum oxide, tin oxide, niobium oxide, zirconium oxide, aluminum oxide, lanthanum oxide and germanium oxide.

14. The method of claim 12 wherein said first coating of soot is silica doped with not more than 20 percent by weight titanium oxide.