Optical coupling circuit element

• US 5,031,991 A
• Filed: 12/01/1989
• Issued: 07/16/1991
• Est. Priority Date: 12/01/1988
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Okumura, Toshiyuki, Nakatsu, Hiroshi, Inoguchi, Kazuhiko, Takiguchi, Haruhisa
• Primary Examiner(s): Ullah, Akm
• Assistant Examiner(s): Wise, Robert E.
• Application Number:
  US07/444,442
• Time in Patent Office: 592 Days
• Field of Search: 350/452, 350/96.18, 350/445, 350/446, 350/96.17
• US Class Current: 385/33
• CPC Class Codes: G02B 3/08 with discontinuous faces, e.g. Fresnel lens diffractive Fresnel lenses G02B5/1876
• CPC Class Codes: G02B 6/4206 Optical features G02B6/4207, G02B6/421 take precedence

Abstract

An optical coupling circuit element providing one transparent substrate, a first micro Fresnel lens formed on one side surface of said substrate, and a second micro Fresnel lens formed on the other side surface of said substrate, so that coherent light incident into said first micro Fresnel lens is projected, through said transparent substrate, on said second micro Fresnel lens to be left therefrom as a collimating beams, which is useful for directing light emitted from coherent source such as semi-conductor laser to optical communication means such as optical fiber for condensation.

Claims

1. An optical coupling circuit element for collimating an emitting beam from a coherent source to direct the light to an optical communication means, comprising:

one transparent substrate;

a first micro Fresnel lens formed on one side surface of said substrate; and

a second micro Fresnel lens formed on the other side surface of said substrate, so that coherent light that is directed into said first micro Fresnel lens is projected through said transparent substrate on said micro Fresnel lens to exit therefrom as a collimating beam.

2. An optical coupling circuit element of claim 1 wherein said coherent source is a semiconductor laser.

3. An optical coupling circuit element of claim 1 wherein said coherent source is a diverging spherical wave.

4. An optical coupling circuit element of claim 1 wherein said collimating beam is a spherical wave converging in a right circular cone shape.

5. An optical coupling circuit element of claim 1 wherein said first and second micro Fresnel lens have horizontal and flat lens surfaces and are arranged in parallel to each other, and an optical axis of said coherent light incident to said first micro Fresnel lens in parallel to an axis perpendicular to the lens surfaces thereof, an optical axis of a projecting light projected from said first micro Fresnel lens onto said second micro Fresnel lens through said transparent substrate and an optical axis of collimating beam leaving said second micro Fresnel lens are each arranged on the same line.

6. An optical coupling circuit element of claim 5 wherein said first micro Fresnel lens is a hologram clement which can project a far field pattern in a substantial circular shape on said second micro Fresnel lens when pitches of lens circles of said first Fresnel lens are made thin on a central axis perpendicular to one central axis of a surface subjected to said coherent light incident into said second micro Fresnel lens in comparison with on the latter axis, and a major axis of an elliptic far field pattern of coherent light incident into said second micro Fresnel lens is adapted to correspond to said one central axis.

7. An optical coupling circuit element of claim 5 wherein said second micro Fresnel lens is a hologram element which is an elliptic shape and causes a circular light projected from said first Fresnel lens to converge as a spherical wave to a top of a right circular cone shape having said circular light as its bottom.

8. An optical coupling circuit element of claims 1 or 5 wherein said collimating beam is in a slanted circular cone shape and is a spherical wave converging from the bottom of said slanted circular cone to its top.

9. An optical coupling circuit element of claim 1 wherein said first and second micro Fresnel lens have horizontal and flat lens surfaces at both sides and are arranged in non-parallel to each other;

and an optical axis of coherent light incident to said first micro Fresnel lens slantwise to an axis perpendicular to the lens surfaces thereof, an optical axis of a light projected from said first micro Fresnel lens onto said second micro Fresnel lens through said transparent substrate and an optical axis of a collimating beam leaving said second micro Fresnel lens are each arranged on the same line.

10. An optical coupling circuit element of claim 1 wherein said first micro Fresnel lens has lens surface which is convex having a central axis at a position displaced at a fixed interval from an optical axis of coherent light in a perpendicular direction thereto, and said second micro Fresnel lens has lens horizontal and flat surface, and an optical axis of coherent light incident to said first micro Fresnel lens slantwise to an axis perpendicular to the lens surfaces thereof, an optical axis of a light projected from said first micro Fresnel lens onto said second micro Fresnel lens through said transparent substrate and an optical axis of a converging bundle of rays leaving said second micro Fresnel lens are each arranged on the same line.

11. An optical coupling circuit element for collecting an outgoing light from a coherent source to direct the light to an optical communication means, comprising one transparent substrate, a first micro Fresnel lens formed on one side surface of said substrate, a reflective mirror formed on the other side surface of said substrate and a second micro Fresnel lens formed in parallel to said first micro Fresnel lens on said one side of said substrate, so that a coherent light incident into said first micro Fresnel lens is projected through said transparent substrate to said reflective mirror, changed in direction by said mirror, and passes through said substrate again to reach said second micro Fresnel lens so as to be left therefrom as a collimating beam.

12. An optical coupling circuit element of claim 11 wherein said coherent source is a semiconductor laser.

13. An optical coupling circuit element set forth in claim 11 wherein said coherent source is a diverging spherical wave.

14. An optical coupling circuit element set forth in claim 11 wherein said collimating beam is a spherical wave converging in a right circular cone shape.

15. An optical coupling circuit element set forth in claim 11 wherein said first micro Fresnel lens has a lens surface perpendicular to an optical axis of said coherent light and said second micro Fresnel lens has a lens surface perpendicular to an optical axis of said collimating beam.

16. An optical coupling circuit element set forth in claim 15 wherein said second micro Fresnel lens is a hologram element which is in an elliptic shape and causes a circular light projected from said first Fresnel lens and reflected by said reflective mirror to converge as a spherical wave to a top of a right circular cone shape spherical wave to a top of a right circular cone shape having said circular light as its bottom.

17. An optical coupling circuit element of claim 11 wherein said first micro Fresnel lens is a hologram element which can project a far field pattern in a substantially circular shape on said second Fresnel lens when pitches of lens circles of said first Fresnel lens are made thin on a central axis perpendicular to one central axis of a surface subjected to coherent incident light in comparison with one the latter axis, and a major axis of an elliptic far field pattern of incident coherent light is adapted to correspond to said one central axis, and said elliptic far field pattern is to be reflected by said reflective mirror.

18. An optical coupling circuit element for collimating a light beam emitted from a light source in order to direct the light to an optical communication apparatus comprising:

a single transparent substrate having a first and second side surface;

a first Fresnel lens formed on a first side surface of said substrate; and

a second Fresnel lens formed on a second side surface of said substrate.

19. An optical coupling circuit element for collecting light from a light source in order to direct the light to an optical communication device comprising:

a single transparent substrate having a first and second substrate side surface;

a first and second Fresnel lens formed on the first substrate side surface; and

a reflective mirror formed on the second substrate side surface.

20. The method of focusing a light beam emitted from a light source to an optical communication device comprising the steps of:

(a) emitting light from the light source;

(b) directing the light to an optical element that is transparent and has two side surfaces, each of the side surfaces containing a Fresnel lens;

(c) passing the light through a first Fresnel lens;

(d) passing the light through the substrate; and

(e) passing the light through a second Fresnel lens so that the light will come in contact with the optical communication device.

21. The method of passing and focusing light from a light source to an optical device comprising the steps of:

(a) providing a transparent substrate having two side surfaces, a first side surface containing two Fresnel lenses, the second side surface containing a mirror;

(b) emitting light from said light source so that it passes through a first Fresnel lens and the transparent substrate;

(c) reflecting the light from step (b) from the mirror;

(d) passing the light through a second Fresnel lens; and

(e) that the light can come in contact with an optical communication device.

22. An optical coupling circuit element for directing light from a coherent source to an optical communication means, comprising:

a transparent substrate having a first and second side surface;

a first micro Fresnel lens formed on a first side surface of said substrate;

a reflective mirror formed on the second side surface of said substrate; and

a second micro Fresnel lens formed in parallel to said first micro Fresnel lens on said first side of said substrate, so that coherent light that is directed into said first micro Fresnel lens is projected through said transparent substrate to said reflective mirror where the light is reflected and passes through said substrate again to reach said second micro Fresnel lens so as to exist therefrom as a collimating beam.