Laser module

Patent metadata

Field	Value
Publication number	US-9837782-B2
Application number	US-201314436383-A
Country	US
Kind code	B2
Filing date	Oct 4, 2013
Priority date	Oct 17, 2012
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

A light incidence plane of the core 15 includes a plurality of planes 15 a to 15 c unparalleled with each other to which a light beam emitted from at least one laser element 21 is entered. When seen on a cross section taken along the longer direction of an optical fiber 10 , light beams entered to a core 15 from the inclined planes 15 b and 15 c inclined to an axis CA of the optical fiber 10 in the plurality of the planes 15 a to 15 c are propagated from a region surrounded by a line and the inclined planes 15 b and 15 c forming an acute angle, the line being passed through the incident points of the light beams entered to the inclined planes 15 b and 15 c and parallel with an axis CA.

First claim

The invention claimed is:

1. A laser module comprising:
a plurality of laser elements; and
an optical fiber including a core to which light beams emitted from the plurality of the laser elements are entered, wherein
a light incidence plane of the core has a convex shape and includes a plurality of planes unparalleled with each other to which a light beam emitted from at least one laser element is entered, and
when seen on a cross section along a longer direction of the optical fiber, a light beam entered to the core from an inclined plane inclined to an axis of the optical fiber in the plurality of the planes is propagated to the inclined plane from a region surrounded by a line and the inclined plane forming an acute angle, the line being passed through an incident point of the light beam entered to the inclined plane and parallel with the axis, wherein, in the region, the line and the inclined plane form the acute angle,
wherein when seen on a cross section along the longer direction of the optical fiber, an expression is satisfied:
θ light +θ angle <θ taper

where a size of an acute angle formed between the inclined plane and the axis is defined as θ taper , a size of an angle that is a corresponding angle of the acute angle and formed between the optical axis and the axis is defined as θ light , and an angle of divergence of a light beam entered from the inclined plane to the core with respect to the optical axis is defined as θ angle .

2. The laser module according to claim 1 , wherein when seen on a cross section along the longer direction of the optical fiber, an expression is satisfied:
θ NA <θ taper

where a maximum angle of incidence of a light beam that does not leak from the core when the light beam is entered to the core from a plane perpendicular to the axis is defined as θ NA .

3. The laser module according to claim 1 , wherein all of expressions are satisfied:

n
core

n
clad

×

sin
(

sin

-
1

(

sin
⁡

(

π
2

-

θ
taper

+

θ
light

+

θ
angle

)

n
core

)

+

θ
taper

)

≧
1

n
core

n
clad

×

sin
(

sin

-
1

(

sin
⁡

(

π
2

-

θ
taper

+

θ
light

-

θ
angle

)

n
core

)

+

θ
taper

)

≧
1

where a refractive index of the core of the optical fiber is defined as n core , and a refractive index of a cladding of the optical fiber is defined as n clad .

4. The laser module according to claim 3 , wherein optical axes of light beams entered from the individual planes to the core are caused to be collimated to the axis.

5. The laser module according to claim 1 , wherein in light beams entered from the individual planes to the core, light beams emitted from at least the two laser elements are condensed on the individual planes through a condenser lens.

6. The laser module according to claim 5 , wherein
the light beams before condensed through the condenser lens are collimated light beams, and
the collimated light beams are collimated to each other.

7. The laser module according to claim 1 , wherein in the plurality of the planes, one plane is a vertical surface perpendicular to the axis.

8. The laser module according to claim 1 , wherein in the plurality of the planes, at least two planes are the inclined planes, and one inclined plane is matched with a face that the other inclined plane is rotated relative to the axis.

9. The laser module according to claim 1 , wherein
the plurality of planes each is a plane in a shape including a longer direction and a shorter direction, and
a light beam emitted from the laser element is entered from the plane in the shape including the longer direction and the shorter direction to the core as a slow axial direction is aligned with the longer direction of the plane in the shape including the longer direction and the shorter direction.

Assignees

• Fujikura Ltd

Inventors

• Sakamoto Shinichi

Classifications

• H01S5/405

  Two-dimensional arrays · CPC title

• G02B6/42

  Coupling light guides with opto-electronic elements · CPC title

• G02B27/09

  Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for {(adapting the beam shape of a laser diode G02B19/0052; adapting the beam shape of an LED G02B19/0061; coupling into light guides using intermediate optical elements G02B6/4204; beam shaping specially adapted for lasers H01S3/005)} · CPC title

• G02B27/10

  Beam splitting or combining systems (polarising systems G02B27/28; mixing and splitting light signals using optical waveguides G02B6/28; {beam shaping, e.g. changing the cross-sectional area, by dividing or superposing multiple light beams G02B27/0905}) · CPC title

• G02B6/0013

  Means for improving the coupling-in of light from the light source into the light guide (coupling light into light guides in general G02B6/42) · CPC title