OPTICAL DEVICE

Abstract

A first optical device has an optical fiber mount with an optical fiber disposed thereon, and an optical demultiplexer for demultiplexing a portion of an optical signal beam transmitted through the optical fiber, as a demultiplexed optical signal beam, and guiding the demultiplexed optical signal beam out of the optical fiber. The optical fiber has a first tapered surface for emitting the demultiplexed optical signal beam therethrough. The first tapered surface is inclined at an angle θ1 of at least 1° to an optical axis of the optical fiber. The distance (h) between the optical axis of the optical fiber and the first tapered surface is progressively greater along the direction in which the optical signal beam travels through the optical fiber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary cross-sectional view of a first optical device according to the present invention;

FIG. 2 is an enlarged cross-sectional view of the optical device taken along line II-II of FIG. 1;

FIG. 3 is a fragmentary cross-sectional view of an optical device according to a comparative example;

FIG. 4 is a fragmentary cross-sectional view of a first modification of the first optical device;

FIG. 5 is a fragmentary cross-sectional view of a second modification of the first optical device;

FIG. 6 is a fragmentary cross-sectional view of a third modification of the first optical device;

FIG. 7 is a fragmentary cross-sectional view of a fourth modification of the first optical device;

FIG. 8 is a fragmentary cross-sectional view of a second optical device according to the present invention; and

FIG. 9 is a fragmentary cross-sectional view of a modification of the second optical device.

Claims

1. An optical device comprising: an optical fiber mount with an optical fiber disposed thereon; andan optical demultiplexer for demultiplexing a portion of an optical signal beam transmitted through said optical fiber, as a demultiplexed optical signal beam, and guiding the demultiplexed optical signal beam out of said optical fiber;said optical fiber having a tapered surface for emitting said demultiplexed optical signal beam therethrough.

2. An optical device according to claim 1, wherein said optical demultiplexer has a slit defined in said optical fiber across an optical axis thereof, and an optical demultiplexing member inserted in the slit for demultiplexing the portion of the optical signal beam transmitted through said optical fiber.

3. An optical device according to claim 1, wherein said tapered surface is inclined at an angle of at least 1° to an optical axis of said optical fiber.

4. An optical device according to claim 1, wherein said tapered surface is spaced from an optical axis of said optical fiber by a distance which is progressively greater along a direction in which said optical signal beam travels through said optical fiber.

5. An optical device according to claim 2, further comprising: an optical path changer for changing an optical path of said demultiplexed optical signal beam guided out of said optical fiber;a waveguide serving as at least a medium from which said demultiplexed optical signal beam is emitted to said optical path changer; anda filter disposed on a surface of said waveguide.

6. An optical device according to claim 5, wherein said waveguide serves as a medium from which said demultiplexed optical signal beam is emitted to said optical path changer and to which said demultiplexed optical signal beam is emitted from said optical path changer.

7. An optical device according to claim 5, wherein said optical demultiplexing member comprises a wavelength demultiplexing filter, and said filter comprises a bandpass filter for passing a light beam in a particular wavelength range of said demultiplexed optical signal beam.

8. An optical device according to claim 5, wherein said waveguide is disposed directly above said optical fiber.

9. An optical device according to claim 5, further comprising a refractive index matching agent placed between at least a surface of said optical fiber and said waveguide.

10. An optical device according to claim 5, wherein said waveguide has a surface facing a surface of said optical fiber and extending substantially parallel to the optical axis of said optical fiber.

11. An optical device according to claim 5, wherein said waveguide has a tapered surface facing a surface of said optical fiber.

12. An optical device according to claim 11, wherein said tapered surface of said waveguide extends substantially parallel to said tapered surface of said optical fiber.

13. An optical device according to claim 11, wherein said tapered surface of said optical fiber is inclined at an angle θ1 to the optical axis of said optical fiber, and said tapered surface of said waveguide is inclined at an angle θ2 to the optical axis of said optical fiber, said angle θ1 and said angle θ2 being different from each other.

14. An optical device according to claim 5, wherein said optical path changer comprises: a guide, said waveguide and said guide being juxtaposed on a surface of said optical fiber; anda totally reflecting film disposed on an end face of said guide which faces said waveguide.

15. An optical device according to claim 14, wherein said tapered surface of said optical fiber doubles as a positioning member for positioning said guide with respect to said optical fiber.

16. An optical device according to claim 5, wherein said optical path changer comprises a totally reflecting film disposed on an end face of said waveguide which is present on the optical path of said demultiplexed optical signal beam.

17. An optical device according to claim 5, wherein said tapered surface of said optical fiber comprises a side surface of a V-shaped groove defined in a surface of said optical fiber.

18. An optical device according to claim 17, wherein said V-shaped groove has an other side surface doubling as a positioning member for positioning said waveguide with respect to said optical fiber.

19. An optical device according to claim 5, further comprising a light-detecting unit disposed on the optical path of said demultiplexed optical signal beam which has passed through said filter disposed on the surface of said waveguide.