Optical part for two-way optical communication

• US 20030198444A1
• Filed: 04/11/2003
• Published: 10/23/2003
• Est. Priority Date: 04/17/2002
• Status: Active Grant

• Current Assignee: Hosiden Corporation
• Original Assignee: Hosiden Corporation
• Inventors: Isoda, Takeshi, Nakagawa, Hiroshi, Mine, Keiji
• Granted Patent: US 6,910,810 B2
• Time in Patent Office: Days
• US Class Current: 385/89
• CPC Class Codes: G02B 6/4214 the intermediate optical element having redirecting reflective means, e.g. mirrors, prisms for deflecting the radiation from horizontal to down- or upward direction toward a device G02B6/4246 takes precedence
• CPC Class Codes: G02B 6/4246 Bidirectionally operating package structures

Abstract

An optical guide 43 is partly buried in a lens 43 on the diameter of its aperture, the lens 43 converging received light incident from the end face of an optical fiber onto a light receiving element 15 and the optical conductor 33 having a refractive index larger than that of the lens 43. The optical guide 33 is composed of a buried portion 33-1 and an extending portion 33-2, and transmitting light 22 incident on the optical guide 33 from the end face 33c of the extending portion 33-2 is reflected by a reflecting surface 33a and launched into the optical fiber. The transmitting light 22 is guided by the optical guide 33 to the end face of the optical fiber without leakage to the receiving-side portion.

Claims

1. An optical part for use in two-way optical communication which performs transmission and reception of light over a single optical fiber, comprising:

converging means for converging received light from said optical fiber onto a light receiving element; and

optical guide means disposed adjacent said converging means, for launching transmitting light from a light emitting element into said optical fiber;

wherein a region dedicated for emitting said transmitting light from said optical guide means to said optical fiber is formed adjacent a region of said converging means on which said received light incident from said optical fiber impinges.

2. The optical part of claim 1, wherein:

said converging means includes a convergent leans disposed opposite the end face of said optical fiber and said optical guide means includes an optical guide having a refractive index larger than that of said convergent lens and buried at its lower end portion on the diameter of an aperture of said convergent lens opposing said optical fiber end face;

wherein said optical guide includes a portion buried in said convergent lens, the bottom of said buried portion forming a reflecting surface inclined with respect to the optical axis of said convergent lens, and a portion extending radially-outwardly of said convergent lens from said buried portion, said transmitting light incident from the end face of said extending portion being reflected by said reflecting surface and launched into said optical fiber end face through said dedicated emitting region.

3. The optical part of claim 2, wherein at least one of said reflecting surface, said end face of said extending portion and the surface of said extending portion of said optical guide disposed opposite said optical fiber end face is spherical.

4. The optical part of claim 2 or 3, wherein that portion of said extending portion of said optical guide means which is outside said convergent lens in the direction of diameter of said convergent lens gradually broadens toward said end face.

5. The optical part of claim 1, wherein said converging means comprises:

a triangular-sectioned prism having a first surface opposite said optical fiber end face, a second surface opposite said light receiving element, and a third surface for reflecting said received light incident thereon through said first surface toward said second surface; and

first and second convergent lenses integrally formed on said first and second surfaces of said prism, respectively;

wherein said optical guide member includes an optical guide buried in said convergent lens on the diameter of the aperture of said first convergent lens opposite said optical fiber end face in the direction of an edge where said first and third surfaces meet; and

wherein said optical guide includes a buried portion whose bottom forms a reflecting surface inclined with respect to the optical axis of said first convergent lens, and a portion extending outwardly of said edge from said buried portion, and has a refractive index larger than that of said received light incident region and a construction in which said transmitting light incident from the end face of said extending portion is reflected by said reflecting surface and launched into said optical fiber end face through said dedicated emitting region.

6. The optical part of claim 5, wherein at least one of said reflecting surface, said end face of said extending portion and the surface of said extending portion of said optical guide disposed opposite said optical fiber end face is spherical.

7. The part of claim 5 or 6, wherein said extending portion of said optical guide gradually broadens outwardly from said edge.

8. The optical part of claim 5 or 6, wherein said third surface is spherical.

9. The optical part of claim 1, wherein said converging means has a lens half of such a configuration as if cut out from a lens in a plane parallel to the optical axis thereof;

wherein said optical guide means has a transmitting prism formed integrally with said lens half on the cut-out face;

wherein said transmitting prism has a first surface which is opposite the face joined to said cut-out face of said lens half and on which said transmitting light is incident, a second surface opposing said optical fiber end face and a third surface for reflecting said transmitting light incident thereon from said first surface toward said second surface; and

wherein said lens half converges said received light from said optical fiber onto said light receiving element.

10. The optical part of claim 9, wherein said converging means includes a box-shaped block integrally formed with the received light emitting surface and a convergent lens formed integrally with the surface of said box-shaped block on the opposite side from said lens half.

11. The optical part of claim 9 or 10, wherein convergent lenses are integrally formed with said first and second surfaces of said transmitting prism, respectively.

12. The optical part of claim 9 or 10, wherein said third surface is concavely curved.

13. The optical part of claim 9, wherein said converging means comprises a receiving prism formed integrally with the light emitting surface of said lens half and formed integrally with said transmitting prism, and a receiving convergent lens for converging light from said receiving prism onto said light receiving element;

and

wherein said receiving prism has said second surface opposite said optical fiber end face, a fourth surface adjoining said second surface and opposite said light receiving element and a fifth surface for reflecting light incident from said second surface to said fourth surface, said transmitting prism and said receiving prism being integrally formed as one-piece prism of pentagonal section.

14. The optical part of claim 13, wherein convergent lenses for converging said received light are integrally formed with said first and second surfaces, respectively.

15. The optical part of claim 13 or 14, wherein said third and fifth surfaces are concavely curved in said transmitting and receiving prisms, respectively.

16. The optical part of claim 14, wherein said convergent lens for converging said received light on said second surface and said convergent lens for converging said transmitting light on said second surface are formed by a single lens;

wherein said third and fifth surfaces are both concavely curved; and

wherein one half portion of said prism through which said received light passes and the other half through which said transmitting light are formed in symmetrical relation.