Micro lens formation at optical fiber ends

• US 4,118,270 A
• Filed: 02/18/1976
• Issued: 10/03/1978
• Est. Priority Date: 02/18/1976
• Status: Expired due to Term

• Current Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Original Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Inventors: Pan, Jing Jong, Barton, James Castle, Arnold, Milton Phillip
• Primary Examiner(s): Powell, William A.
• Assistant Examiner(s): Bokan, Thomas
• Application Number:
  US05/658,880
• Time in Patent Office: 958 Days
• Field of Search: 196/2, 196/8, 196/15, 196/345, 196/24, 350/96 C, 350/175 NG, 350/175 SL, 350/178, 350/96.18, 156/625, 156/659, 156/663, 156/668, 156/904, 156/654, 156/651, 427/162-164, 427/169, 427/272, 427/273, 427/275, 427/259, 427/287, 427/430 R, 427/430 B
• US Class Current: 216/24
• CPC Class Codes: B29D 11/00365 Production of microlenses lenticular sheets B29D11/00278
• CPC Class Codes: B29D 11/00663 Production of light guides
• CPC Class Codes: C03C 25/104 to obtain optical fibres
• CPC Class Codes: C03C 25/68 by etching
• CPC Class Codes: G02B 6/262 Optical details of coupling light into, or out of, or between fibre ends, e.g. special fibre end shapes or associated optical elements

Abstract

Method of formation of lenses at optical fiber ends to increase the coupling efficiency thereof. In a first embodiment, the end of the optical fiber is masked with a substance non-soluble in the etching reagent. The portion of the coating at the very end of the fiber is then removed and the fiber end immersed in an etching reagent. The etching reagent serves to dissolve the uncoated portion of the fiber. By controlling the amount of time that the fiber end is in the reagent, different lens shapes may be formed. In a second embodiment, the fiber end is dipped into a liquid epoxy compound whereby a portion of the epoxy is deposited onto the fiber end. The surface tension of the portion deposited thereon draws the liquid epoxy into the desired lens shape. The epoxy is then hardened to form a permanent lens structure on the fiber end.

Claims

1. The method of forming a lens onto the end of an optical fiber through chemical etching, said optical fiber end having a general contour which is different then the desired lens shape, comprising the steps of:

immersing said fiber end into an etching solution to such an extent that the entire said fiber end is immersed in said etching solution and so that the entire cross-sectional surface of said fiber end is etched by said etching solution,

timing said immersion for an interval being long enough to allow removal of enough of said fiber end by the action of said etching solution alone so that only the desired lens shape remains, and

removing said fiber end from said etching solution at the conclusion of said interval.

2. The method of claim 1 wherein the step of timing said immersion includes the step of selecting the length of said interval in accordance with the desired shape of the lens to be formed.

3. The method of forming a lens onto the end of an optical fiber comprising the steps of

masking a longitudinal section of said fiber adjacent the fiber end with a coating which is nonsoluble in a selected etching solution, and

immersing at least the entire said fiber end into said selected etching solution to remove uncoated portions thereof through the action of said etching solution, alone, to the extent that only the desired lens shape remains.

4. The method of claim 3 wherein the step of masking a section of said fiber comprises the steps of coating said fiber end together with said longitudinal section adjacent thereto with said coating which is nonsoluble in said selected etching solution and removing said coating so formed from said fiber end so that only said longitudinal section adjacent said fiber end remains coated.

5. The method of claim 4 wherein said longitudinal section comprises the entire said fiber except said fiber end.

6. A method of forming a lens on an optical fiber end comprised of the steps of immersing a selected amount of said fiber end into an optically transparent liquid, withdrawing said fiber end from said liquid so that only a drop of said liquid remains on said fiber end and the surface tension of said drop draws said liquid into the desired lens shape, and hardening said liquid so as to form a solid lens permanently affixed to said fiber end, wherein the resultant lens shape is dependent upon the amount of said fiber immersed in said liquid and wherein said method further comprises the additional step of controlling said selected amount in accordance with the lens shape desired.