JP2005148538A - Optical waveguide and laser beam emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical waveguide and a laser light emitting device that can more efficiently and easily converge respective laser beams emitted by a plurality of light emission parts of a semiconductor laser array. <P>SOLUTION: The optical waveguide 20 has an incidence surface 20c where laser beams are made incident, a projection surface 20e, and a transmission area extending from the incidence surface to the emitting surface, is equipped with a long-axis direction converging means 20a of converging laser beams along a long axis on the incidence surface or transmission area, and a short-axis direction converging means which totally reflects the incident laser beams in a short axis direction to travel toward the emitting surface, is formed to nearly the same main width in the short axis direction up to a specified distance from the incidence surface in the traveling direction of the laser beams, and is formed so that at least a part of the width in the short axis direction from the position at the specified distance to the emitting surface becomes gradually narrower from the main width. The width Wslow of the emitting surface in the short axis direction is made narrower than the width Wsin of the incidence surface in the short axis direction and the laser beams are converged. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical waveguide that condenses laser light, and a laser light emitting device that condenses and outputs laser light.

FIG. 7 shows an example of a schematic configuration of a conventional semiconductor laser condensing device. Semiconductor laser light (hereinafter referred to as “laser light”) emitted from the light emitting portion 12 of the active layer 14 of the semiconductor laser (laser diode or the like) is substantially elliptical in a plane perpendicular to the traveling direction of the laser light 2. The elliptical laser beam 2 has a major axis direction and a minor axis direction. The ellipse becomes larger as the distance from the light emitting unit 12 becomes longer. Laser light emitted from the semiconductor laser array 10 having a plurality of light emitting portions 12 two-dimensionally arranged in the major axis direction (X-axis direction) and the minor axis direction (Y-axis direction) is collected in the optical fiber 30. 2. Description of the Related Art Semiconductor laser concentrators that emit light and increase the output of laser light are known.
For example, when a semiconductor laser is used as a light source of a laser processing apparatus, it is necessary to increase the output of laser light used for processing. However, the output intensity of laser light emitted from a single light emitting unit is limited. Therefore, the laser light emitted from the plurality of light emitting units is condensed using a lens group or the like to increase the output of the laser light.

As a technique of a conventional semiconductor laser condensing device, as shown in FIG. 7, a lens group and an optical fiber 30 are provided, and a long-axis collimating lens array 70 is provided between the laser light emitting unit 12 and the optical fiber 30. It has been proposed to arrange the lenses in the order of the long-axis direction condensing lens 80 and the short-axis direction condensing lens array 90 to condense the laser light onto the optical fiber 30 and increase the output of the laser light (for example, , See Patent Document 1).
JP 2000-98191 A

In order to efficiently focus the laser beam emitted from the light emitting unit 12 of the semiconductor laser onto the optical fiber 30 and increase the output of the laser beam, the laser beam from more light emitting units is incident on the thinner optical fiber. The incident light is incident on the incident end face at a smaller incident angle and efficiently incident on the optical fiber without being reflected outside (closer to the incident end face at a right angle). It is necessary to enter at an angle. As a result, the angle between the traveling direction of the laser light in the optical fiber and the longitudinal direction of the optical fiber becomes smaller, the laser light travels while being totally reflected in the optical fiber, and loss due to leakage to the outside of the optical fiber. Can be suppressed.
Here, the laser light emitted from the light emitting unit 12 travels while spreading in the major axis direction and the minor axis direction. When condensing laser light that travels while spreading, the lens itself is required to have very high accuracy, and the lens arrangement position is also required to have very high accuracy.
In a conventional semiconductor laser condensing device (for example, Japanese Patent Application Laid-Open No. 2000-98191), in the long axis direction where the interval between the light emitting portions is relatively wide, the light is once converted into parallel light and then condensed. In the short axis direction where the interval between the light emitting parts is relatively narrow, the diameter of the lens is very small and it is difficult to arrange the lenses.

In a conventional semiconductor laser condensing device (for example, Japanese Patent Laid-Open No. 2000-98191), as shown in FIG. 7, each light emitting unit 12 (m, n) (m row n column, FIG. 7) of the semiconductor laser array 10 In the example, laser light emitted from 5 rows and 16 columns is transmitted through the long-axis direction collimating lens array 70, transmitted through the long-axis direction condensing lens 80, and further transmitted through the short-axis direction condensing lens array 90. Thus, the light is incident on the optical fiber 30 (s, t) (s row t column, 1 row 8 column in the example of FIG. 7).
In all of the drawings, the coordinate axes are the Z axis as the traveling direction of the laser beam, the X axis as the major axis direction, and the Y axis as the minor axis direction.
Note that all the drawings include portions described in dimensions, ratios, and the like that are different from actual dimensions in order to facilitate explanation or to facilitate comparison and the like.

FIGS. 8A and 8B show the state of each lens and laser light in the configuration of FIG. 7 (conventional semiconductor laser condensing device). FIG. 8A shows two laser beams emitted from two light emitting units arranged in the minor axis direction and five lasers emitted from five light emitting units arranged in the major axis direction. A total of 10 laser beams of light are condensed on one optical fiber. 8A is a view of FIG. 7 viewed from the X-axis direction (viewed from above), and FIG. 8B is a view of FIG. 7 viewed from the Y-axis direction (view from the side). ).
In a commonly used semiconductor laser array, in the minor axis direction, the width of each light emitting portion 12 (Dw in FIG. 8A) is about 0.15 mm, and the distance between the light emitting portion and the light emitting portion (see FIG. Dp) in 8 (A) is about 0.25 mm. Further, the divergence angle (θiny in FIG. 8A) in the minor axis direction of the laser light emitted from each light emitting portion is about 3.5 °.
In addition, the interval between the light emitting portions adjacent to each other in the major axis direction (Dh in FIG. 8B) is about 1.75 mm, and the thickness of each light emitting portion (Dt in FIG. 8B) is about 0. 002 mm. Further, the divergence angle (θinx in FIG. 8B) in the major axis direction of the laser light emitted from each light emitting portion is about 40 °.

For example, two laser beams are condensed in the short axis direction and five laser beams are condensed in the long axis direction on the optical fiber 30. Further, the light is condensed so that the incident angle in the minor axis direction (θouty in FIG. 8A) is about 10 ° or less (with a smaller incident angle).
In this case, in order to collect light most efficiently, in FIG. 8A, the short-axis direction condensing lens array 90 is arranged before the laser beams emitted from the light emitting units 12 adjacent in the short-axis direction overlap. There is a need. In the case of the above numerical values, the position where the laser beams overlap is a position of about 1.6 mm from the light emitting unit 12.
However, it is necessary to arrange the long-axis direction collimating lens array 70 and the short-axis direction condensing lens array 90 within a distance from the light emitting unit 12 to about 1.6 mm, which is practically very difficult to arrange. .

In this case, if the focal length (f90) of the short-axis direction condensing lens array 90 is set to the distance from the light emitting unit 12 to the short-axis direction condensing lens array 90 (in this case, about 1.6 mm), the short distance The condensing efficiency in the axial direction is almost optimal, and the distance from the light emitting unit 12 to the optical fiber 30 (L in FIG. 8A) is about 3.2 mm.
However, for example, laser beams emitted from five light emitting units arranged at intervals of 1.75 mm in the long axis direction have an incident angle in the long axis direction (θoutx in FIG. 8B) of less than 10 °. Therefore, a distance of about 19.85 mm or more is necessary, and it is very difficult to collect a necessary number of laser beams.

Therefore, it is necessary to solve the following problems.
The distance between the short-axis direction condensing lens array 90 and the light emitting unit 12 is short. For this reason, it is difficult to appropriately arrange the long-axis direction collimating lens array 70 and the short-axis direction condensing lens array 90 within a predetermined distance. Further, the position of the optical fiber 30 is also a short distance from the light emitting unit 12, and if the incident angle (θoutx) in the major axis direction is set small, the number of laser beams that can be condensed in the major axis direction is reduced.
The present invention was devised in view of the above points, and an optical waveguide capable of condensing each laser beam emitted from a plurality of light emitting portions of a semiconductor laser array more efficiently and more easily. Another object is to provide a laser light emitting device.

As means for solving the above-mentioned problems, the first invention of the present invention is an optical waveguide as defined in claim 1.
The optical waveguide according to claim 1 is incident from an incident surface on which a laser beam traveling while expanding into a shape having a major axis and a minor axis is incident, an exit surface from which the incident laser beam is emitted, and an incident surface. An optical waveguide having a long axis direction condensing means for converging the incident laser light in the long axis direction on the incident surface or the transmission area. The optical waveguide causes the incident laser light to be totally reflected in the minor axis direction and travel toward the exit surface, and the minor axis from the incident surface to a predetermined distance in the laser beam traveling direction. The width of the short axis direction is formed with substantially the same main width, and at least a part from the position of the predetermined distance to the exit surface is formed so that the width of the short axis direction is gradually narrowed from the main width. Light means are provided.

The second invention of the present invention is an optical waveguide as defined in claim 2.
An optical waveguide according to a second aspect is the optical waveguide according to the first aspect, wherein the shape of the short-axis direction condensing means is a linear shape or a curved shape including an exponential function shape.

According to a third aspect of the present invention, there is provided a laser light emitting device as set forth in the third aspect.
The laser light-emitting device according to claim 3 is a light-emitting unit that is arranged at a first predetermined interval in the major axis direction and two-dimensionally arranged at a second predetermined interval in the minor axis direction. A semiconductor laser array having a plurality of light emitting portions that emit laser light that travels while spreading in a shape having a short axis, and laser light emitted from each light emitting portion of the semiconductor laser array in a major axis direction on a light emitting surface. A plurality of optical waveguides each having a long-axis direction condensing means for condensing at a position corresponding to each light-emitting portion, and a plurality of incident surfaces arranged at positions facing the predetermined position on the emission surface of each optical waveguide And optical condensing means for condensing laser light emitted from the exit surface of the optical fiber.
Each optical waveguide is formed such that the width in the minor axis direction on the incident surface is a main width that substantially corresponds to the length in the minor axis direction of one light emitting portion, and the incident surface with respect to the traveling direction of the laser beam. From the position of the predetermined distance to the exit surface so that the width in the short axis direction gradually decreases from the main width. The short axis direction condensing means formed is provided.

  If the optical waveguide according to claim 1 is used, in the short axis direction where the divergence angle is smaller than the major axis direction, while slightly increasing the divergence angle in the minor axis direction (while suppressing the divergence angle within an allowable range), A structure capable of reducing the light condensing diameter in the minor axis direction of the laser light can be easily realized.

If the optical waveguide according to claim 2 is used, the laser beam that has reached the exit surface has a slightly large divergence angle in the major axis direction but a small condensing diameter and a divergence angle in the minor axis direction. Although it becomes a little larger, since the condensing diameter can be reduced, the condensing efficiency can be further improved. In this case, in the minor axis direction, by adjusting the linear shape or exponential function shape of the short axis direction condensing means (for example, by changing the slope of the straight line), the divergence angle is suppressed within an allowable range. Since the light diameter can be reduced to reduce the difference between the major axis diameter and the minor axis diameter, and the difference between the major axis divergence angle and the minor axis divergence angle, the light is emitted from the exit surface. By making the laser light enter the optical fiber having a smaller diameter, the density of the laser light can be increased and the light collection efficiency can be further improved.
For example, when the emitted laser light is incident on the optical fiber, the difference between the major axis diameter and the minor axis diameter of the laser light incident on the optical fiber is small, and the major axis divergence angle is Since the difference from the divergence angle in the minor axis direction is small, a thinner optical fiber and an optical fiber with a more appropriate NA value (numerical aperture) can be selected, and the light collection efficiency can be further improved.

  Moreover, if the laser light emitting device according to claim 3 is used, for example, the laser light emitted from the semiconductor laser array in which the light emitting portions are two-dimensionally arranged can be efficiently condensed on a plurality of thinner optical fibers. Further, the laser light emitted from the optical fiber can be condensed by the condensing means, and the output of the laser light (per unit area) can be further increased more easily.

The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration diagram of an embodiment in which an optical waveguide array 200 using the optical waveguide 20 of the present invention is applied to a laser light emitting device 1.
In the present embodiment shown in FIG. 1, the distance between the semiconductor laser array 10 and the optical fiber 30 can be greatly increased as compared with the conventional laser focusing apparatus shown in FIG. In this embodiment, it is also possible to set the length to several centimeters to several tens of centimeters or more according to the length of the optical waveguide array 200 with respect to the traveling direction of the laser light. For this reason, since the incident angle to the optical fiber 30 can be reduced, the laser light can be condensed more efficiently.
Further, the long-axis direction collimating lens array 70, the long-axis direction focusing lens 80, and the short-axis direction focusing lens array 90 are omitted from the conventional laser focusing apparatus shown in FIG. Since the array 200 is provided, the configuration is simplified, and adjustment at the time of assembly (fine adjustment of the arrangement position of each lens, etc.) is very easy as compared with the conventional laser focusing apparatus.

● [Overall structure (Fig. 1)]
In the present embodiment shown in FIG. 1, the light emitting unit 12 (m, n) (m rows and n columns, in the example of FIG. 1, 5 rows and 8 columns) is divided into a plurality of groups (Grp) for each major axis direction. The laser light for each group is condensed by each optical waveguide 20 (s, t) (s rows and t columns, 1 row and 8 columns in the example of FIG. 1), and each optical fiber 30 (s, t) (s The incident light enters the row t column, which is 1 row 8 columns in the example of FIG.

The semiconductor laser array 10 includes a plurality of light emitting units 12 and two-dimensionally arranges semiconductor lasers having a single light emitting unit, or stacks or arranges array type semiconductor lasers having a plurality of light emitting units in a row. Alternatively, it is composed of a stack type semiconductor laser arranged two-dimensionally. In this embodiment, a so-called stack type laser diode is used.
The optical waveguide array 200 is configured by arranging a plurality of optical waveguides 20 (s, t) corresponding to each group (Grp) in the major axis direction of the light emitting units 12 (m, n) in the minor axis direction. Yes. The laser light incident in each optical waveguide 20 (s, t) travels in the incident optical waveguide 20 (s, t) while being substantially totally reflected in the minor axis direction (details will be described later). .
The optical waveguide array 200 has a long axis so that a plurality of laser beams incident from the light emitting units 12 of the semiconductor laser array 10 are collected on the incident surface of each optical fiber 30 (s, t) with respect to the long axis direction. Condensed (bundled or aggregated) in the direction.
In the following, “bundling” refers to collecting a plurality of laser beams without substantially reducing the diameter of each laser beam, and “aggregating” refers to reducing the diameter of each laser beam or reducing the diameter of the plurality of laser beams. Means to collect laser light. “Condensing” means increasing the output of laser light using a method of “bundling” or “aggregating”.

  The incident surface of each optical fiber 30 (s, t) is connected to each optical waveguide 20 (s, t) from a predetermined position (position where laser light is collected) on the emission surface of each optical waveguide 20 (s, t). The laser beam condensed at t) is incident. The condensing lens 100 (condensing means) collects the laser beams emitted from the emission surfaces of the optical fibers 30 (s, t) bundled in an arbitrary shape by the bundle unit 100a at respective predetermined positions. Shine. As a result, the plurality of laser beams emitted from the plurality of light emitting units 12 (m, n) of the semiconductor laser array 10 are condensed at a predetermined position and can be used for laser processing or the like. The output can be increased.

● [Configuration of optical waveguide 20 (FIG. 2)]
Next, the configuration of the optical waveguide 20 will be described with reference to FIG. The optical waveguide 20 includes an incident surface 20c on which laser light is incident, an output surface 20e that emits the incident laser light, and a transmission region (where the laser light incident from the incident surface 20c is transmitted toward the output surface 20e). A region between the incident surface 20c and the exit surface 20e).
The width in the minor axis direction on the incident surface 20c of the optical waveguide 20 is formed to be a width (main width: Wsin) corresponding to the length in the minor axis direction of one light emitting unit 12. The width (width Wsin) in the minor axis direction is substantially the same width up to a predetermined distance from the incident surface 20c (a predetermined distance with respect to the traveling direction of the laser light and a distance La in FIG. 2A). Is formed. And at least a part from the position of the predetermined distance to the emission surface 20e is formed so that the width in the minor axis direction is gradually narrowed from the width Wsin. This portion corresponds to the short axis direction light collecting means. In the example shown in FIG. 2A, the width in the minor axis direction is gradually narrowed from the width Wsin toward the width Wslow at the distance Lb, and the width Wslow is maintained at the distance Lc. Yes. In this way, the width Wslow in the minor axis direction on the exit surface 20e is formed to be narrower than the width Wsin in the minor axis direction on the incident surface 20c.
Although the optical waveguide 20 shown in the present embodiment is not narrowed at the distance Lc, the width in the minor axis direction is from Wsin to the width Wslow from the distance Lb toward the emission surface 20e. I try to make it narrower. Thus, the short axis direction light condensing means only needs to be formed in at least a part of the region up to the emission surface 20e.

The shape that narrows the width Wslow in the minor axis direction may be a straight line (see FIG. 2D) that narrows at a constant rate, or a curved line (see FIG. 2E). Also good. Further, in the vicinity of the emission surface 20e, a portion having a constant width (a portion having a distance Lc) may be provided in order to make the incident surface of the optical fiber 30 contact easily.
Distance The shape gradually narrowing the width in the minor axis direction at Lb portions have various shapes, the inventors have in simulation, exponential shape (y = a * e ^x shape along a, a: The constant, e: the base of the natural logarithm) was confirmed to have the best light collection efficiency.
Further, the long axis direction condensing means 20a is provided on the incident surface 20c or the transmission region (see FIGS. 2B and 2C), and is a cylindrical lens having an axis parallel to the short axis direction. Yes, each incident laser beam is condensed in the major axis direction (see FIG. 5B).
The optical waveguide 20 shown in FIG. 2 (C) has a refractive index n1 on the incident surface 20c side with respect to the long-axis direction condensing means 20a and refraction on the output surface 20e side with respect to the long-axis direction condensing means 20a. A member having a refractive index n2 is brought into contact with each other, and refractive index n1> refractive index n2 is set. In the case of refractive index n1 <refractive index n2, the direction of unevenness is reversed.
In the present embodiment, the optical waveguide 20 is made of quartz glass, but is not limited to this material.
Further, the long axis direction condensing means 20a only needs to be able to condense the incident laser light at a predetermined position Pout (see FIG. 2A) on the emission surface 20e with respect to the long axis direction, and the shape and the like of this embodiment are as follows. It is not limited to the form.

● [Formation method for gradually reducing the width of the optical waveguide in the minor axis direction (Fig. 3)]
Next, a method of forming a shape in which the width of the optical waveguide 20 in the short axis direction is gradually narrowed will be described with reference to FIGS.
First, an optical waveguide array 200 in which flat optical waveguides 20 are stacked in the minor axis direction is prepared. The thickness of each optical waveguide 20 in the minor axis direction and the gap between adjacent optical waveguides 20 are appropriately set according to the position of the light emitting unit 12 of the semiconductor laser array 10 to be used. The gap between adjacent optical waveguides 20 is filled with a gap member 22 having a refractive index lower than that of the optical waveguide 20 or a gap member 22 that totally reflects laser light.
Then, as shown in FIGS. 3 (B) and 3 (C), the light emitting surface 20e side of the optical waveguide array 200 is ground by the grinding means 50 including the grinding wheel 51 that is rotated by the motor 52. A shape in which the width in the minor axis direction of 20 is gradually narrowed is formed. Since the shape of the grinding portion of the grinding wheel 51 can be variously shaped with very high accuracy, the shape of the short-axis direction condensing means that gradually narrows the width in the short-axis direction is linear or curved. Etc., and can be finished in any shape.

● [Diameter and divergence angle of the laser beam reaching the exit surface of the optical waveguide (FIGS. 4 and 5)]
Next, the diameter and the divergence angle of the laser light 2 that has entered from the incident surface 20c of the optical waveguide 20 and reached the output surface 20e of the optical waveguide 20 will be described with reference to FIG.
In FIG. 4A, in the optical waveguide 20z in which the width (width Wsin) in the minor axis direction is constant, the laser light 2 incident from the incident surface 20c at the incident angle θ1 reaches the output surface 20e while being totally reflected. It shows how to do. 4A, when “refractive index in air: n1” <“refractive index of optical waveguide 20z: n2” <“refractive index of optical fiber 30: n3”, θ1> θ2 (= θslow)> θ3.
For example, when θ1 is 3.5 °, the diameter in the minor axis direction of the laser beam 2 (laser beam that has reached the exit surface 20e of the optical waveguide 20) incident on the incident surface of the optical fiber 30 is the width Wslow (the width Wsin). The same), and the divergence angle θslow (incident angle θslow) in the minor axis direction is smaller than 3.5 °.

In FIG. 4B, the width Wsin is constant from the incident surface 20c to a predetermined distance (distance La) with respect to the width (width Wsin) in the minor axis direction, and from the position of the distance La to the exit surface 20e. In the figure, in the optical waveguide 20 whose width in the minor axis direction is gradually narrowed, the laser light 2 incident from the incident surface 20c at the incident angle θ1 reaches the output surface 20e while being totally reflected. 4B, when “refractive index in the atmosphere: n1” <“refractive index of the optical waveguide 20: n2” <“refractive index of the optical fiber 30: n3”, θ1> θ2 and θ2 <θ4 < θslow and θslow> θ6. For example, when θ1 is 3.5 °, the diameter of the laser beam 2 incident on the incident surface of the optical fiber 30 (the laser beam 2 reaching the exit surface 20e of the optical waveguide 20) in the minor axis direction is a width Wslow (width Wsin). The spread angle θslow (incident angle θslow) in the minor axis direction is appropriately set by the shape of the minor axis direction condensing means (in this example, gradually narrowed by the angle φ), It can be adjusted to any divergence angle. Further, the width Wslow in the short axis direction can be adjusted with the shape of the short axis direction light collecting means set appropriately.
Thereby, the diameter Dfb of the optical fiber 30 shown in FIG. 4 (B) can be made smaller than the diameter Dfb of the optical fiber 30 shown in FIG. 4 (A), and the light collection efficiency can be further improved. Note that the shape of the short-axis direction condensing means is selected so that the incident angle θslow to the optical fiber 30 does not exceed the NA value of the optical fiber 30.

In the above description, it has been described that the width Wslow in the minor axis direction and the divergence angle θslow in the minor axis direction can be adjusted on the exit surface 20e of the optical waveguide 20. Next, it will be described with reference to FIG. 5B that the long axis width Wfast and the long axis divergence angle θfast can be adjusted on the emission surface 20e of the optical waveguide 20. FIG.
5A is a view of the semiconductor laser array 10 to the optical fiber 30 in FIG. 1 as seen from the long axis direction (X-axis direction), and FIG. 5B is from the short axis direction (Y-axis direction). FIG.
FIG. 5A shows a laser beam emitted from the light emitting portion 12 (m, n) of the semiconductor laser array 10 using the optical waveguide array 200 in which the optical waveguides 20 shown in FIG. It is a figure which shows a mode that light is condensed to a short-axis direction, and injects into the optical fiber.
FIG. 5B shows a state in which each laser beam incident from the incident surface 20c reaches a predetermined position Pout on the emission surface 20e while being condensed in the major axis direction. In the long axis direction, the length of the laser light reaching the emission surface 20e is set by appropriately setting the focal length f (not shown) and the position of the center P (m, n) of the long axis direction condensing means 20a. It is possible to adjust the axial diameter and the light collection position (in this case, the predetermined position Pout).

Further, as shown in FIG. 5B, the divergence angle θfast in the major axis direction of the laser light reaching the emission surface 20e is the maximum distance Dv in the major axis direction of the light emitting section 12 and the laser progression of the optical waveguide array 200. It depends on the direction length Lt.
As shown in FIG. 5B, the length Lt of the optical waveguide array 200 in the laser advancing direction may be made longer in order to further reduce the divergence angle θfast in the major axis direction. However, the shape or the center position P (m, n) of the long axis direction condensing means 20a has a certain amount of error, and if the length Lt is made longer, this error is amplified and is increased in the long axis direction. There is a possibility that the light exits from the predetermined position Pout beyond the allowable range on the emission surface 20e where the condensed laser light has reached, and cannot enter the optical fiber 30.
Therefore, an optical fiber 30 having an NA value that allows laser light to enter at a feasible divergence angle θfast is selected (in this embodiment, the divergence angle θslow is smaller than the divergence angle θfast).

● [Effect of this embodiment (FIG. 6)]
As described above, in the present embodiment, in the laser light emitting device shown in FIG. 1, the width Wfast in the major axis direction (the condensed diameter in the major axis direction) of the laser light incident on the incident surface of the optical fiber 30. ) And the width Wslow (condensing diameter in the short axis direction) can be adjusted, and the divergence angle (incident angle) θfast in the major axis direction and the divergence angle (incident angle) θslow in the minor axis direction can be adjusted. Can be adjusted.
FIG. 6A is a diagram showing the incident surface of the optical fiber 30 and the state of the condensed laser light when the divergence angle θslow in the minor axis direction and the width Wslow in the minor axis direction are not adjusted. FIG. 6B is a diagram showing the incident surface of the optical fiber 30 and the state of the condensed laser light when the divergence angle θslow in the minor axis direction and the width Wslow in the minor axis direction are appropriately adjusted. is there. Obviously, in the drawing shown in FIG. 6B, the diameter Dfb of the optical fiber 30 can be made smaller, so that the light collection efficiency can be further improved.

The NA value of the optical fiber 30 is selected based on the larger side of the divergence angle θfast and the divergence angle θslow, and it is meaningless to reduce only one of the divergence angles. Therefore, even if the side with the smaller divergence angle (in this case, the divergence angle θslow) is adjusted closer to the side with the larger divergence angle (in this case, the divergence angle θfast), the light collection efficiency is not affected.
The diameter Dfb of the optical fiber 30 is selected based on the larger side of the width Wfast and the width Wslow, and it is almost meaningless to reduce only one of the widths. Therefore, if the side having the larger width (in this case, the width Wslow) can be adjusted to approach the side having the smaller width (in this case, Wfast), the diameter Dfb of the optical fiber 30 can be further reduced. The light efficiency can be further improved.
In the present embodiment, by forming the optical waveguide 20 so that the width in the minor axis direction is gradually narrowed, θslow on the side with a smaller divergence angle is made closer to θfast on the side with a larger divergence angle, and the width (collection) is increased. It is possible to make Wslow on the side with the larger (light diameter) closer to Wfast on the side with the smaller width (condensed diameter).

Thereby, the occupation area S of the focused laser beam on the incident surface of the optical fiber 30 can be adjusted from the state of FIG. 6A to the state of FIG. 6B, and the smaller diameter Dfb. The optical fiber 30 can be used, and the light collection efficiency can be further improved.
Further, the beam parameter product (beam quality) represented by the product of the beam radius of the condensed laser beam and the divergence angle (half angle) can be further improved.

The optical waveguide 20, the optical waveguide array 200, and the laser light emitting device 1 of the present invention are not limited to the shape and configuration described in the present embodiment, and various modifications, additions, and the like can be made without changing the gist of the present invention. Can be deleted.
Further, the shapes, sizes, and the like of the optical waveguide 20 and the optical fiber 30 are not limited to the description and drawings of the embodiments. The optical waveguide 20 can be made of various materials such as quartz glass.
Further, the overall shape of the optical waveguide 20 in each embodiment is not limited to the shape shown in FIG.
The numerical values used in the description of the present embodiment are examples, and are not limited to these numerical values.
Further, the above (≧), the following (≦), the greater (>), the less (<), etc. may or may not include an equal sign.

  The optical waveguide 20 and the laser light emitting device 1 of the present invention can be applied to various devices using laser light such as a laser processing device.

1 is a schematic configuration diagram of an embodiment in which an optical waveguide array 200 using an optical waveguide 20 of the present invention is applied to a laser light emitting device 1. FIG. It is a figure explaining the structure of the optical waveguide 20 of this invention. It is a figure explaining the formation method of the shape of the short axis direction condensing means which narrows the width | variety of the short axis direction of the optical waveguide 20 of this invention gradually. It is a figure explaining the diameter and divergence angle of the laser beam 2 which entered from the entrance surface 20c of the optical waveguide 20 of this invention, and reached | attained the output surface 20e of the said optical waveguide 20. FIG. It is a figure explaining that the width | variety Wfast of a major axis direction and the divergence angle (theta) fast of a major axis direction can be adjusted in the output surface 20e of the optical waveguide 20 of this invention. It is a figure explaining the effect of this Embodiment. It is a figure explaining schematic structure of the conventional semiconductor laser condensing device. In the conventional semiconductor laser condensing apparatus, it is a figure explaining a mode that the arrangement | positioning position of each lens and the laser beam which passed each lens are condensed.

Explanation of symbols

2 (m, n) laser beam 10 semiconductor laser array 12 (m, n) light emitting portion 20 (s, t) optical waveguide 20a long axis direction condensing means 20c incident surface 20e emitting surface 22 gap member 200 optical waveguide array 30 ( s, t) Optical fiber 100 Condensing lens (condensing means)
100a Bundle part

Claims (3)

An incident surface on which laser light traveling while expanding into a shape having a major axis and a minor axis is incident, an exit surface that emits incident laser light, and laser light incident from the incident surface is transmitted toward the exit surface An optical waveguide having a long-axis direction condensing means for condensing incident laser light in a long-axis direction on an incident surface or a transmission region,
The optical waveguide is
The incident laser light is totally reflected in the minor axis direction and travels toward the exit surface,
The width in the minor axis direction is formed with substantially the same main width from the incident surface to the predetermined distance with respect to the traveling direction of the laser beam, and at least a part from the position of the predetermined distance to the emission surface is in the minor axis direction. It is provided with short axis direction light collecting means formed so that the width is gradually narrowed from the main width,
An optical waveguide characterized by that. The optical waveguide according to claim 1,
The shape of the short-axis direction condensing means is a linear shape or a curved shape including an exponential function shape,
An optical waveguide characterized by that. A light emitting section arranged in a long axis direction at a first predetermined interval and two-dimensionally arranged in a short axis direction at a second predetermined interval, and traveling while expanding into a shape having a long axis and a short axis A semiconductor laser array having a plurality of light emitting portions for emitting light;
A plurality of optical waveguides provided with long-axis condensing means corresponding to each light-emitting part for condensing laser light emitted from each light-emitting part of the semiconductor laser array at a predetermined position on the emission surface in the long-axis direction When,
A plurality of optical fibers in which an incident surface is arranged at a position facing the predetermined position on the emission surface of each optical waveguide;
A laser light emitting device comprising a condensing means for condensing laser light emitted from an emission surface of an optical fiber,
Each optical waveguide is
The width in the minor axis direction on the incident surface is formed to a main width that substantially corresponds to the length in the minor axis direction of one light emitting portion,
The width in the minor axis direction is formed with substantially the same main width from the incident surface to the predetermined distance with respect to the traveling direction of the laser beam, and at least a part from the position of the predetermined distance to the emission surface is in the minor axis direction. It is provided with short axis direction light collecting means formed so that the width is gradually narrowed from the main width,
A laser light emitting device characterized by that.

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