Light guide device, manufacturing method, and laser diode module

Patent metadata

Field	Value
Publication number	US-10379291-B2
Application number	US-201615154401-A
Country	US
Kind code	B2
Filing date	May 13, 2016
Priority date	Nov 15, 2013
Publication date	Aug 13, 2019
Grant date	Aug 13, 2019

Abstract

A double mirror (Mi) is made of a first mirror (Mi1) that is mounted on a top surface of a base plate (B) and a second mirror (Mi2) that is mounted on a top surface of the first mirror (Mi1). The first mirror (Mi1) has a reflective surface (S1) for reflecting an input beam. The second mirror (Mi2) has a reflective surface (S2) for reflecting the input beam which has been reflected by the reflective surface (S1).

First claim

The invention claimed is:

1. A light-guiding device that converts an input beam bundle made of a plurality of input beams to an output beam bundle made of a plurality of output beams, comprising:
double mirrors which (i) correspond to the respective input beams and (ii) are separated from each other,
each of the double mirrors being made of a first mirror that is mounted on a certain flat surface and a second mirror that is mounted on the first mirror,
the first mirror having a first reflective surface which (i) reflects a corresponding one of the input beams and (ii) is arranged so that there is an angle of θ1 between the certain flat surface and the first reflective surface,
the second mirror having a second reflective surface which (i) reflects the corresponding one of the input beams which has been reflected by the first reflective surface and (ii) is arranged so that there is an angle of θ2 between the certain flat surface and the second reflective surface,
the θ1 satisfying the following expressions:
(90°−θ angle )=−θ2 y× 2−(90°−φ1)×2−(90°−θ1×2); and

θ1≠45°, and

the θ2 satisfying the following expressions:
(90°−φ2)−θ1 y× 2−(90°−θ2×2); and

θ2≠45°,

where (i) θ angle is an angle between the corresponding one of the input beams and a corresponding one of the output beams, (ii) φ1 is an angle between an optical axis of the corresponding one of the input beams and a normal of the certain flat surface, (iii) φ2 is an angle between an optical axis of the corresponding one of the output beams and the normal of the certain flat surface, (iv) θ1y is a rotation angle which shows how much the first mirror has rotated from a first reference direction around the normal of the certain flat surface serving as a rotation axis, which first reference direction is a direction of the first mirror while an orthogonal projection of a normal vector of the first reflective surface onto the certain flat surface is parallel to an orthogonal projection of the optical axis of the corresponding one of the input beams onto the certain flat surface, and (v) θ2y is a rotation angle which shows how much the second mirror has rotated from a second reference direction around the normal of the certain flat surface serving as a rotation axis, which second reference direction is a direction of the second mirror while an orthogonal projection of a normal vector of the second reflective surface onto the certain flat surface is orthogonal to the orthogonal projection of the optical axis of the corresponding one of the input beams onto the certain flat surface.

2. The light-guiding device as set forth in claim 1 , wherein:
in each of the double mirrors, respective orientations of the first mirror and the second mirror are adjusted so that propagation directions of the output beams constituting the output beam bundle coincide with a certain direction.

3. The light-guiding device as set forth in claim 2 , wherein:
in each of the double mirrors, respective positions of the first mirror and the second mirror are adjusted so that optical axes of the output beams constituting the output beam bundle are aligned at equal intervals within a certain plane.

4. The light-guiding device as set forth in claim 1 , wherein:
the certain flat surface and a bottom surface of the first mirror are adhered to each other via an adhesive layer formed between the certain flat surface and the bottom surface, the adhesive layer having a uniform thickness; and
a top surface of the first mirror and a bottom surface of the second mirror are adhered to each other via an adhesive layer formed between the top surface of the first mirror and the bottom surface of the second mirror, the adhesive layer having a uniform thickness.

5. The light-guiding device as set forth in claim 1 , wherein:
a thickness of an adhesive layer formed between the certain flat surface and a bottom surface of the first mirror and a thickness of an adhesive layer formed between a top surface of the first mirror and a bottom surface of the second mirror each are smaller than a dimensional tolerance of each of the double mirrors.

6. A method for producing the light-guiding device as set forth in claim 1 , comprising the step of:
adjusting respective orientations of the first mirror and the second mirror of each of the double mirrors so that propagation directions of the output beams constituting the output beam bundle coincide with a certain direction.

7. The method as set forth in claim 6 , further comprising the step of:
adjusting respective positions of the first mirror and the second mirror of each of the double mirrors so that respective optical axes of the output beams are aligned at equal intervals within a certain plane.

8. An LD module comprising:
a plurality of LD elements; and
a light-guiding device that converts an input beam bundle made of a plurality of laser beams that have respectively been emitted from the plurality of LD elements, to an output beam bundle made of a plurality of output beams,
the light guiding device including double mirrors which (i) correspond to the respective LD elements and (ii) are separated from each other,
each of the double mirrors being made of a first mirror that is mounted on a certain flat surface and a second mirror that is mounted on the first mirror,
the first mirror having a first reflective surface which (i) reflects a corresponding one of the laser beams which has been emitted from a corresponding one of the LD elements and (ii) is arranged so that there is an angle of θ1 between the certain flat surface and the first reflective surface,
the second mirror having a second reflective surface which (i) reflects the corresponding one of the laser beams which has been reflected by the first reflective surface and (ii) is arranged so that there is an angle of θ2 between the certain flat surface and the second reflective surface,
the θ1 satisfying the following expressions:
(90°−θ angle )=−θ2 y× 2−(90°−φ1)×2−(90°−θ1×2); and

θ1≠45°, and

the θ2 satisfying the following expressions:
(90°−φ2)−θ1 y× 2−(90°−θ2×2); and

θ2≠45°,

where (i) θ angle is an angle between the corresponding one of the laser beams and a corresponding one of the output beams, (ii) φ1 is an angle between an optical axis of the corresponding one of the laser beams and a normal of the certain flat surface, (iii) φ2 is an angle between an optical axis of the corresponding one of the output beams and the normal of the certain flat surface, (iv) θ1y is a rotation angle which shows how much the first mirror has rotated from a first reference direction around the normal of the certain flat surface serving as a rotation axis, which first reference direction is a direction of the first mirror while an orthogonal projection of a normal vector of the first reflective surface onto the certain flat surface is parallel to an orthogonal projection of the optical axis of the corresponding one of the laser beams onto the certain flat surface, and (v) θ2y is a rotation angle which shows how much the second mirror has rotated from a second reference direction around the normal of the certain flat surface serving as a rotation axis, which second reference direction is a direction of the second mirror while an orthogonal projection of a normal vector of the second reflective surface onto the certain flat surface is orthogonal to the orthogonal projection of the optical axis of the corresponding one of the laser beams onto the certain flat surface.

9. The LD module as set form in claim 8 , further comprising:
a converging lens that converges the output beam bundle on an incident edge surface of an optical fiber,
wherein in each of the double mirrors, respective orientations of th

Assignees

• Fujikura Ltd

Inventors

• Sakamoto Shinichi
• Kumeta Shohei

Classifications

• H01S5/02248

  Electricity · mapped topic

• G02B6/4249

  comprising arrays of active devices and fibres · CPC title

• G02B6/4214

  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 title

• G02B27/12

  operating by refraction only · CPC title

• H01S5/0071

  for beam steering, e.g. using a mirror outside the cavity to change the beam direction · CPC title