Techniques for manufacturing a waveguide with a three-dimensional lens

• US 7,267,930 B2
• Filed: 06/04/2004
• Issued: 09/11/2007
• Est. Priority Date: 06/04/2004
• Status: Expired due to Fees

• Current Assignee: POA Sana Liquidating Trust
• Original Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Inventors: Payne, Jonathan N.
• Primary Examiner(s): McPherson; John A.
• Application Number:
  US10/862,007
• Publication Number:
  US 20050271983A1
• Time in Patent Office: 1,194 Days
• Field of Search: None
• US Class Current: 430/321
• CPC Class Codes: G02B 2006/121 Channel; buried or the like
• CPC Class Codes: G02B 2006/12102 Lens
• CPC Class Codes: G02B 2006/12173 Masking
• CPC Class Codes: G02B 6/1228 Tapered waveguides, e.g. integrated spot-size transformers for coupling with fibres G02B6/305
• CPC Class Codes: G02B 6/138 by using polymerisation

Abstract

Optical transmission structures include a waveguide and an optical lens wherein the optical lens has a sufficiently large thickness to allow the formation of a curved front lens surface that collimates transmitted light rays so that they travel within a plane that is coplanar to a working surface. The present invention also relates to a technique for manufacturing the optical transmission structure, which involves the use of a photopolymer material. The optical transmission structure can be implemented in various systems such as a system for optical data input.

Claims

1. A method for manufacturing an optical structure comprising:

applying a layer of photopolymer material onto a bottom cladding layer, which is formed over a support substrate;

providing a patterned grayscale mask that allows a certain pattern of light to pass through the mask at varying intensities;

exposing the layer of photopolymer material to light that is directed through the grayscale mask such that selected portions of the photopolymer material are exposed to an exposure gradient of light, the exposure gradient of light having light rays of varying intensities;

developing the layer of photopolymer material with a developer solution to remove portions of the layer of photopolymer material such that the remaining portion of the photopolymer material forms a waveguide having a first height and that is integrated with an optical lens having a second height, wherein the second height of the optical lens is greater than the first height of the waveguide; and

rinsing the layer of photopolymer material to wash away the removed portions of the photopolymer material.

2. A method as recited in claim 1 wherein the optical lens has a three-dimensionally contoured shape.

3. A method as recited in claim 1 wherein the developing operation further comprises:

forming the waveguide such that the waveguide forms a lengthwise structure that has a first end that is integrated with the optical lens and a second end that is connected to a light source or a light detector.

4. A method as recited in claim 1 wherein the developing operation further comprises:

forming the optical lens such that the optical lens has an in-plane collimating lens curve that has an outline that is substantially defined within at least a plane that is perpendicular to a top surface of the support substrate, wherein light rays transmitted from the waveguide are collimated by the optical lens so that the light rays are emitted through the in-plane collimating lens curve in a plane that is substantially coplanar to the top surface of the support substrate.

5. A method as recited in claim 4 wherein the in-plane collimating lens curve defines a front lens surface that extends from the supporting surface to a maximum height of the optical lens.

6. A method as recited in claim 4 wherein the developing operation further comprises:

forming the optical lens such that the optical lens has a directionally collimating lens curve that has an outline that is substantially defined within at least a plane that is coplanar with the top surface of the support surface, wherein the light rays transmitted from the waveguide are collimated such that substantially all of the light rays emitted through the directionally collimating lens curve are parallel to each other and travel in a single direction.

7. A method as recited in claim 4 wherein the developing operation further comprises:

forming the optical lens such that the optical lens has an inclined back surface that has a first edge that joins the waveguide and a second edge that extends to a maximum height of the optical lens.

8. A method as recited in claim 7 further comprising:

applying a top cladding layer over the waveguide.

9. A method as recited in claim 8 wherein the inclined back surface is substantially flat and is inclined at an angle equal to at least ^sin−

1(.n,2−

n₂²/n₃), wherein n1 is the index of refraction of the waveguide, n2 is the index of refraction of the top cladding layer or the bottom cladding layer, whichever is larger, and n3 is the index of refraction of the optical lens.

10. A method as recited in claim 4 wherein the developing operation further comprises:

forming the optical lens such that the optical lens has a width that expands as the optical lens extends away from the waveguide.

11. A method of manufacturing an optical structure comprising:

applying a layer of photopolymer material onto a support substrate;

exposing the layer of photopolymer material to an exposure gradient of light, the exposure gradient of light being formed by directing light through a patterned grayscale mask that allows the light to pass through the mask at varying intensities;

developing the layer of photopolymer material with a developer solution to remove portions of the layer of photopolymer material such that the remaining portion of the photopolymer material forms a waveguide that is integrated with an optical lens wherein the optical lens has a height that is larger than a height of the waveguide and the optical lens has an inclined and curved front lens surface; and

rinsing the layer of photopolymer material to wash away the removed portions of the photopolymer material.

12. A method as recited in claim 11 wherein the exposing operation further comprises:

exposing the photopolymer material to the exposure gradient of light such that during the developing operation a waveguide is formed that has an elongated shape with a first end that is integrated with the optical lens and a second end that is connected to a light source or a light detector.

13. A method as recited in claim 11 wherein the developing operation further comprises:

forming the optical lens such that the optical lens has a directionally collimating lens curve that has an outline that is substantially defined within at least a plane that is coplanar with the top surface of the support surface.

14. A method as recited in claim 11 wherein the developing operation further comprises:

forming the optical lens such that the optical lens has an inclined back surface that has a first edge that joins the waveguide and a second edge that extends to a maximum height of the optical lens.

15. A method as recited in claim 11 further comprising:

selecting the material that forms the support substrate such that its index of refraction allows the support substrate to act as a bottom cladding layer.

16. A method of manufacturing an optical structure comprising:

applying a layer of photopolymer material onto a bottom cladding layer, which is formed upon a support substrate;

exposing the layer of photopolymer material to light that is directed through a patterned grayscale mask that allows a certain pattern of light to pass through the mask at varying intensities such that selected portions of the photopolymer material are exposed to varying intensities of light;

developing the layer of photopolymer material with a developer solution to remove portions of the layer of photopolymer material such that the remaining portion of the photopolymer material forms a waveguide that is integrated with an optical lens, the optical lens having a height that is higher than a height of the waveguide,

wherein the optical lens has a front lens surface having a curvature that is defined within three dimensions,

wherein light rays transmitted from the waveguide are collimated by the optical lens so that the light rays are emitted through the front lens surface in a plane that is substantially coplanar to a top surface of the support substrate; and

rinsing the layer of photopolymer material to wash away the removed portions of the photopolymer material.

17. A method as recited in claim 16 wherein the developing operation further comprises:

forming the optical lens such that the optical lens has a directionally collimating lens curve that has an outline that is substantially defined within at least a plane that is coplanar with the top surface of the support surface, wherein the light rays transmitted from the waveguide are collimated such that substantially all of the light rays emitted through the directionally collimating lens curve are parallel to each other and travel in a single direction.

18. A system for manufacturing an optical structure comprising:

a support substrate having a top surface;

a bottom cladding layer formed over the top surface of the support substrate;

a layer of photopolymer material this applied to the bottom cladding layer;

a light source that emits light; and

a patterned grayscale mask having a grayscale pattern that allows a desired pattern of light from the light source to shine onto the layer of photopolymer material, the grayscale pattern also allowing light to pass through the grayscale mask at different intensity levels, wherein a waveguide having a first height and an integrated optical lens having a second height is formed in the photopolymer material layer through a photolithography process, wherein the second height of the optical lens is larger than the first height of the waveguide.

19. A system as recited in claim 18 wherein the optical lens has a front lens surface having a curvature that is defined within three dimensions, wherein light rays transmitted from the waveguide are collimated by the optical lens so that the light rays are emitted through the front lens surface in a plane that is substantially coplanar to a top surface of the support substrate.

20. A system as recited in claim 19 wherein the front lens surface has a directionally collimating lens curve that has an outline that is substantially defined within at least a plane that is coplanar with the top surface of the support surface, wherein the light rays transmitted from the waveguide are collimated such that substantially all of the light rays emitted through the directionally collimating lens curve are parallel to each other and travel in a single direction.