Optical coupler for connecting a light source to an optical transmission line

• US 4,257,672 A
• Filed: 12/28/1978
• Issued: 03/24/1981
• Est. Priority Date: 12/28/1978
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Balliet, Layton
• Primary Examiner(s): Corbin, John K.
• Assistant Examiner(s): Lee, John D.
• Application Number:
  US05/973,939
• Time in Patent Office: 817 Days
• Field of Search: 350/96.15, 350/96.17, 350/96.18, 350/96.20, 350/175 SL, 350/179, 350/320, 250/227, 357/17
• US Class Current: 385/35
• CPC Class Codes: G02B 6/4203 Optical features
• CPC Class Codes: G02B 6/4204 the coupling comprising intermediate optical elements, e.g. lenses, holograms encapsulated active devices H01S5/02208, H01L33/52
• CPC Class Codes: G02B 6/4206 Optical features G02B6/4207, G02B6/421 take precedence

Abstract

An optical coupler for optically coupling an LED to an optical fiber includes a transparent spherical shell surrounding a transparent spherical core. The index of refraction of the core is greater than of the spherical shell. A surface is formed on the opposite side of the coupler for coupling the optical fiber to the optical coupler, and a cylinder is used to mount the optical coupler at a predetermined distance from the LED in an orientation maximizing the amount of light entering the optical fiber.

Claims

1. An optical coupler for coupling a relatively wide emission light source to an optical transmission line having a relatively small cross sectional area comprising:

a lens structure that is transparent to light and is comprised of a core region having a first index of refraction and a shell region enclosing said core region and having a second index of refraction, the first index of refraction being greater than the second index of refraction;

means for mounting the relatively wide emission light source adjacent one side of said lens structure for impinging the light rays from the light source upon said lens structure, the light rays being refracted towards the optical transmission line by said lens structure; and

means for coupling the optical transmission line to the opposite side of said lens structure from the wide emission light source for receiving light.

2. The optical coupler of claim 1 wherein said core region and shell region are each spherical.

3. The optical coupler of claim 1 wherein said means for mounting comprises:

a cylinder of a predetermined length and having a diameter that is less than the outside diameter of said shell region;

means for mounting the wide emission light source adjacent the center of one end of said cylinder; and

means for securing the lens structure on the opposite end of said cylinder relative to the wide emission light source at a predetermined distance from the wide emission light source and in an orientation maximizing the amount of light entering the optical transmission line.

4. The optical coupler of claim 1 wherein said means for mounting comprises:

a substrate having the wide emission light source mounted thereon;

a groove formed in the substrate adjacent the wide emission light source; and

means for securing the lens structure in said groove at a predetermined distance from the wide emission light source and in an orientation maximizing the amount of light entering the optical transmission line.

5. The optical coupler of claim 1 wherein said means for coupling further comprises a surface formed in said lens structure for conforming to the end of the transmission line.

6. The optical coupler of claim 1 wherein said core region is a liquid.

7. The optical coupler of claim 1 wherein at least one of said regions is constructed of a solid material.

8. An optical coupler for coupling a light source to an optical transmission line comprising:

a first transparent shell portion having a first index of refraction and having outer and inner curved surfaces;

a second transparent shell portion having a second index of refraction and having at least an inner curved surface, said first and second shell portions having oppositely oriented curvatures with said inner surfaces of said shell portions being disposed in a spaced apart opposing relationship;

a transparent core having a third index of refraction and being disposed between said first and second shell portions, said core including first and second curved surfaces mating with said inner surfaces of said first and second shell portions, respectively, the third index of refraction being greater than the first and second indices of refraction;

means for mounting the light source adjacent said first shell portion for impinging light rays from the light source through said first shell portion, through said core, and into said second shell portion; and

means for coupling the optical transmission line to the second shell portion for receiving light that is transmitted by the light source.

9. The optical coupler of claim 8 wherein the first and second indices of refraction are equal.

10. The opitcal coupler of claim 8 wherein said means for mounting comprises:

a cylinder of a predetermined length having a diameter that is less than the diameter of the first shell portion;

means for mounting the light source adjacent the center of one end of the cylinder; and

means for securing the first shell portion on the opposite end of the cylinder relative to the light source at a predetermined distance from the light source and in an orientation maximizing the amount of light entering the optical transmission line.

11. The optical coupler of claim 8 wherein said means for mounting comprises:

a substrate having the light source mounted thereon;

a groove formed in the substrate adjacent the light source; and

means for securing the first and second shell portions and the core portion in the groove at a predetermined distance from the light source in an orientation maximizing the amount of light entering the optical transmission line.

12. The optical coupler of claim 8 wherein said means for coupling comprises a surface formed in said second shell portion conforming to the end of the transmission line.

13. The optical coupler of claim 8 wherein said core is a transparent fluid having a selected index of refraction and being contained by said first and second shell portions.

14. The method of optically coupling a wide emission light source to an optical transmission line comprising the steps of:

mounting the wide emission light source adjacent a first transparent shell portion;

impinging light rays from the wide emission light source on the first shell portion having a first selected index of refraction;

refracting the light rays with the first shell portion in a direction towards a transparent core portion having a second selected index of refraction that is greater than the first index of refraction;

refracting the light rays with the core portion to converge in a direction towards a second shell portion;

optically coupling the end of the optical transmission line with the second shell portion; and

introducing the converged light rays into the optical transmission line.