Laminated optical waveguide array, beam collecting device and laser emission device

• US 6,819,861 B2
• Filed: 06/27/2003
• Issued: 11/16/2004
• Est. Priority Date: 06/27/2002
• Status: Expired due to Fees

• Current Assignee: Toyoda Koki Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyoda Koki Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Ota, Hiromichi, Niino, Yasuo, Katoh, Yoshinobu
• Primary Examiner(s): Lee, John R.
• Assistant Examiner(s): Souw, Bernard E.
• Application Number:
  US10/606,756
• Publication Number:
  US 20040028371A1
• Time in Patent Office: 508 Days
• Field of Search: 385/105-123, 385/129-132, 385/24, 385/31, 385/33, 385/49, 385/88, 359/204, 359/364, 250/227-1-2
• US Class Current: 385/146
• CPC Class Codes: G02B 6/04 formed by bundles of fibres G02B6/24 takes precedence
• CPC Class Codes: G02B 6/08 with fibre bundle in form of plate
• CPC Class Codes: G02B 6/2848 having refractive means, e.g. imaging elements between light guides as splitting, branching and/or combining devices, e.g. lenses, holograms
• CPC Class Codes: G02B 6/4206 Optical features G02B6/4207, G02B6/421 take precedence
• CPC Class Codes: G02B 6/4249 comprising arrays of active devices and fibres
• CPC Class Codes: G02B 6/425 Optical features semiconductor laser arrays H01S5/40; hybrid LED arrays H01L25/0753; monolithic LED arrays H01L27/153
• CPC Class Codes: H01S 3/094057 by tapered duct or homogenized light pipe, e.g. for concentrating pump light
• CPC Class Codes: H01S 5/4012 Beam combining, e.g. by the use of fibres, gratings, polarisers, prisms
• CPC Class Codes: H01S 5/4025 Array arrangements, e.g. constituted by discrete laser diodes or laser bar H01S5/42 takes precedence
• CPC Class Codes: H01S 5/405 Two-dimensional arrays

Abstract

A beam collecting device and a laser emission device are disclosed incorporating a laminated optical waveguide array and refraction means therein. The laminated optical waveguide array is composed of a plurality of plate-like optical waveguides made of a material having a predetermined refractive index and a plurality of spacer members having a lower refractive index than that of said optical waveguides and arranged alternately with said optical waveguides. The spacer members take the form of cylindrical members, spherical members or plate-like members. The beam collecting device and laser emission device comprise a semiconductor laser array having a plurality of laser emitting parts arranged in fast and slow axis directions, the optical waveguide array, optical fibers and a collective lens. The laser emitting parts are divided into plural groups separated in the slow axis direction. Each of the optical waveguides collects plural laser beams from the laser emitting parts of a corresponding group aligned in the fast axis direction to an emission surface thereof and emits them to a corresponding one of the optical fibers. The refraction means is provided at the emission surface of each waveguide, at an incidence surface of each optical fiber or therebetween, so that the laser beam emitted from the emission surface of the waveguide at an acute angle is refracted to enter into the optical fiber at a gentle angle. Thus, laser beams entered into each optical fiber, without shining therethrough, are efficiently collected to the collective lens to be emitted to a target position.

Claims

1. A beam collecting device comprising:

a semiconductor laser array having a plurality of laser emitting parts which are arranged in fast and slow axis directions in a plane normal to the traveling direction of emitted laser beams, each for emitting a laser beam of an elliptical cross-section which spreads in said fast and slow axis directions as it travels, said laser emitting parts being grouped into plural groups separated in said slow axis direction; and

a laminated optical waveguide array composed of a plurality of optical waveguides arranged in said slow axis direction to be in alignment respectively with said plural groups, each of said optical waveguides being provided with beam collecting means at an incidence surface thereof for collecting laser beams emitted from said laser emitting parts of each group in said fast axis direction toward a predetermined position thereby to emit the collected laser beams from an emission surface thereof.

2. A beam collecting device as set forth in claim 1, wherein said laminated optical waveguide array comprises:

a plurality of plate-like optical waveguides made of a material having a predetermined refractive index; and

a plurality of spacer members having a lower refractive index than that of said optical waveguides and arranged alternately with said optical waveguides.

3. A beam collecting device as set forth in claim 2, wherein each of said spacer members takes the form of one of a cylinder, a sphere and a plate.

4. A beam collecting device as set forth in claim 3, wherein a vacancy which is not occupied by said spacer member between the adjoining waveguides is filled with a resin having a smaller refractive index than that of said optical waveguides, whereby said adjoining waveguides are secured to each other.

5. A beam collecting device as set forth in claim 3, further comprising:

a securing member for pressuring said laminated optical waveguides at opposite ends thereof in the direction of lamination so as to secure the waveguides entirely.

6. A beam collecting device as set forth in claim 5, wherein said laminated optical waveguide array further comprises:

buffer members having a smaller refractive index than said optical waveguides and each arranged between each of the opposite ends of said laminated optical waveguides and said securing member.

7. A laser emission device comprising:

a semiconductor laser array having a plurality of laser emitting parts which are arranged in a fast axis direction as well as in a slow axis direction each for emitting a laser beam of an elliptical cross-section which spreads in said fast and slow axis directions as it travels;

a plurality of optical fibers;

a collective lens; and

a laminated optical waveguide array composed of a plurality of plate-like optical waveguides made of a material having a predetermined refractive index and a plurality of spacer members having a lower refractive index than that of said optical waveguides and arranged alternately with said optical waveguides;

said optical waveguides being arranged in almost substantially the same space as said laser emitting parts of said semiconductor laser array in said slow axis direction, each having substantially the same width as the length of each of said laser emitting parts, and each having an incidence surface extending in said fast axis direction and an emission surface opposite to said incidence surface in the traveling direction of said laser beam;

said optical waveguides being laminated in said slow axis direction of said semiconductor laser array so that plural laser beams emitted from plural laser emitting parts separated from other laser emitting parts in said slow axis direction are entered into said incidence surface of a corresponding one of said optical waveguides to be collected in said fast axis direction and so that the collected laser beams are emitted from said emission surface of said corresponding optical waveguide;

said optical fibers being arranged in said slow axis direction to make incidence surfaces thereof respectively face said emission surfaces of said optical waveguides and having beam emission end portions bundled to take a predetermined shape so that laser beams emitted from said optical waveguides are emitted from said beam emission end portions of said optical fibers to be collected to said predetermined shape; and

said collective lens being provided for collecting plural laser beams emitted from said beam emission end portions of said optical fibers to a target position.

8. A beam collecting device comprising:

an optical waveguide for collecting a beam entered into an incidence surface thereof to a predetermined position in a predetermined direction and for emitting said beam from an emission surface;

an optical fiber; and

refraction means provided between said optical waveguide and said optical fiber for diminishing the angle which the beam refracted at an incident surface of said optical fiber makes with the axis of said optical fiber in comparison with the angle which the beam before being refracted at said emission surface of said optical waveguide makes with the axis of said optical fiber.

9. A beam collecting device as set forth in claim 8, wherein said refraction means comprises a filler having a predetermined refractive index and interposed between said emission surface of said optical waveguide and said incidence surface of said optical fiber.

10. A beam collecting device as set forth in claim 8, wherein:

said predetermined position is either outside or inside said optical waveguide; and

said refraction means comprises a curved surface of either a concave or a convex curved in said fast axis direction, said curved surface being formed at at least one of said emission surface of said optical waveguide and said incidence surface of said optical fiber in dependence on said predetermined position and in dependence on the refractive index of said optical waveguide, the refractive index between said emission surface of said optical waveguide and said incidence surface of said optical fiber and the refractive index of said optical fiber.

11. A laser emission device comprising:

a semiconductor laser array having a plurality of laser emitting parts which are arranged in fast and slow axis directions in a plane normal to the traveling direction of laser beams emitted, each for emitting a laser beam of an elliptical cross-section which spreads in said fast and slow axis directions as it travels, said laser emitting parts being divided into plural groups separated in said slow axis direction;

an optical waveguide array composed of a plurality of optical waveguides each provided with beam collecting means at an incidence surface thereof for collecting laser beams emitted from said laser emitting parts of each group in said fast axis direction and toward a predetermined position thereby to emit the collected laser beams from an emission surface thereof;

a plurality of optical fibers arranged in alignment respectively with said optical waveguides each for entering said collected laser beams emitted from said emission surface of one of said optical waveguides aligned therewith into an incidence surface thereof to emits said collected laser beams from an emission end portion thereof;

a collective lens for further collecting said collected laser beams emitted from each of said optical fibers; and

refraction means for diminishing the angle which each of said collected laser beams refracted at said incident surface of each of said optical fibers makes with the axis of each said optical fiber in comparison with the angle which each of said collected laser beams before being refracted at said emission surface of said optical waveguide makes with the axis of each said optical fiber.

12. A laser emission device as set forth in claim 11, wherein said refraction means comprises a filler filled between said emission surface of each of said optical waveguides and said incidence surface of each of said optical fibers aligned with each said optical waveguide.

13. A laser emission device as set forth in claim 11, wherein said refraction means comprises a curved surface having one of a concave and a convex which are curved in said fast axis direction, said curved surface being formed at at least one of said emission surface of each of said optical waveguides and said incidence surface of each of said optical fibers aligned therewith.

14. A laser emission device as set forth in claim 13, wherein:

said predetermined position to which each of said optical waveguides collects said laser beams is either outside or inside each said optical waveguide; and

whether to form said curved surface at said emission surface of each said optical waveguide or at said incidence surface of each said optical fiber and whether to make said curved surface either concave or convex depend on said predetermined position, the refractive index of said optical waveguides, the refractive index between said emission surface of each said optical waveguide and said incidence surface of each said optical fiber and the refractive index of said optical fibers.