Graded optical waveguides

• US 4,423,925 A
• Filed: 07/28/1981
• Issued: 01/03/1984
• Est. Priority Date: 07/13/1979
• Status: Expired due to Fees

• Current Assignee: Times Fiber Communications Incorporated (Amphenol Corporation)
• Original Assignee: Times Fiber Communications Incorporated (Amphenol Corporation)
• Inventors: Dabby, Franklin W., Chesler, Ronald B.
• Primary Examiner(s): Lee, John D.
• Application Number:
  US06/287,703
• Time in Patent Office: 889 Days
• Field of Search: 350/96.29, 350/96.30, 350/96.31, 350/96.34, 65/2, 65/3.1, 65/3.11, 65/3.12, 65/13
• US Class Current: 385/124
• CPC Class Codes: C03B 2201/10 doped with boron C03B2201/14 takes precedence
• CPC Class Codes: C03B 2203/24 Single mode [SM or monomode]
• CPC Class Codes: C03B 37/01205 starting from tubes, rods, fibres or filaments C03B37/014 takes precedence
• CPC Class Codes: C03B 37/01466 Means for changing or stabilising the diameter or form of tubes or rods C03B37/01861 takes precedence
• CPC Class Codes: C03B 37/01493 Deposition substrates, e.g. targets, mandrels, start rods or tubes

Abstract

A process for preparing a glass rod having a graded refractive index for use as the start rod in the production of optical waveguides is disclosed. The process comprises depositing and sintering borosilicate particles on a glass rod to form a rod having a larger diameter than the original fused silica rod and drawing this rod to obtain a start rod having the same diameter as the original glass rod but exhibiting a partially radially graded refractive index. Optical waveguides prepared from such graded start rods have a more uniformly graded radial index of refraction profile.

Claims

1. An optical waveguide comprising (i) a core comprised of a central area of pure fused silica of constant refractive index and an outer region of borosilicate exhibiting a radially decreasing refractive index and (ii) a cladding of borosilicate of constant refractive index, lower than the refractive indices present in said core, characterized in that said central area of constant refractive index comprises less than 10% of the cross-sectional area of said waveguide.

2. The optical waveguide as defined by claim 1, wherein the ratio of boron oxide to silica in said cladding increases with radial distance from said core.

3. The optical waveguide as defined by claim 1, wherein the ratio of boron oxide to silica varies from zero at the center of the waveguide to approximately 3 at the circumference thereof.