JP2003347647A - Multiplexing laser light source and fiber array light source - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easy-to-produce high output high luminance multiplex laser light source, and a high output low cost fiber array light source. <P>SOLUTION: Laser beams B1-B7 emitted from GaN based semiconductor lasers LD1-LD7 are condensed through a condenser lens 20 and converged onto the incident end face of the core 30a of a multimode optical fiber 30. A condensed beam from the condenser lens 20 has an elliptical beam cross-section having a long diameter of 16.5 μm and a short diameter of 10 μm. When the condensed beam is coupled with the circular cross-section multimode optical fiber having a diameter of 15 μm, a part of the condensed beam is kicked. Since the core 30a of the multimode optical fiber 30 being used in the embodiment has a long diameter of 25 μm although the short diameter thereof is 15 μm, the condensed beam can be coupled efficiently. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combined laser light source and a fiber array light source, and in particular, a combined laser light source for combining a plurality of laser beams using an optical fiber;
The present invention relates to a fiber array light source in which a plurality of optical fiber emission ends of the combined laser light source are arranged.

[0002]

2. Description of the Related Art Conventionally, as a light source for generating laser light in the ultraviolet region, a wavelength conversion laser, excimer laser, argon, which converts infrared light emitted from a semiconductor laser pumped solid-state laser into third harmonics in the ultraviolet region A laser or the like is used. GaN that oscillates at wavelengths near 400 nm
-Based semiconductor lasers have also been proposed (Jpn.Appl.Phys.Let
t., Vol. 37.p.L1020.1998.).

The use of these light sources as a light source for an exposure apparatus for exposing a photosensitive material having sensitivity in a wavelength band of 350 to 420 nm has been studied. The light source used in the exposure apparatus is required to have a sufficient output for exposing the photosensitive material, and to have high reliability and low cost.

[0004]

However, the wavelength conversion laser has a problem that the wavelength conversion efficiency is very low and it is extremely difficult to obtain a high output. For example,
At the present practical level, a solid-state laser medium is excited with a 30 W (watt) semiconductor laser to generate a 10 W fundamental wave (106
4nm), and 3W second harmonic (wavelength 5)
32W), and only the third harmonic (wavelength 355nm) of 1W, which is the sum frequency of both, is obtained.
In this case, the semiconductor laser has an electro-optical conversion efficiency of about 50% and an ultraviolet light conversion efficiency of about 1.7%. In addition, since an expensive optical wavelength conversion element is used, the apparatus cost is considerably high.

In addition, the excimer laser has a problem that the apparatus is large and the manufacturing cost and maintenance cost are high, and the argon laser has a very low electro-optical conversion efficiency of 0.005% and a long life. There is a problem that it is as short as about 1000 hours.

On the other hand, in a GaN semiconductor laser,
Since a low dislocation GaN crystal substrate cannot be obtained, a low dislocation region of about 5 μm is formed by a crystal growth method called “Epitaxial Lateral Over Growth (ELOG)”, and a laser region is formed on this low dislocation region. Attempts have been made to achieve high output and high reliability by forming the same. However, even in a GaN-based semiconductor laser manufactured by this method, it is difficult to obtain a substrate with a low dislocation over a large area, and a high-power laser of 500 mW to 1 W class has not yet been commercialized.

For this reason, as another attempt to increase the output of the semiconductor laser, multi-cavity and fiber light source bundling have been studied. In multicavity,
High output is achieved by forming a plurality of cavities in a single element. For example, 100m in one element
When 100 cavities for outputting W light are formed, 1
An output of 0 W can be obtained. However, it is difficult to form a large number of cavities with high yield,
It lacks reality. In particular, in a GaN-based semiconductor laser in which it is difficult to obtain a yield of 99% or more even in the case of a single cavity, it is even more difficult to form a multicavity with a high yield.

Also, in the fiber light source bundling, a fiber light source in which a laser beam emitted from a single semiconductor laser is coupled to an end face of a single multi-mode optical fiber is used, and the multi-mode optical fiber of this fiber light source is used. High output is achieved by bundling a plurality. Usually, a laser having an output of about 30 mW (milliwatt) is used as a semiconductor laser, and therefore, an output of about 1 W is obtained by bundling 48 multimode optical fibers of the above-mentioned structural unit. However, when trying to increase the output of this light source, there is a problem that the number of optical fibers to be bundled increases, the emission luminance decreases and the cost increases.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a combined laser light source that is easy to manufacture and can achieve high output and high brightness. It is in. Another object of the present invention is to provide a fiber array light source with high output and low cost.

[0010]

In order to achieve the above object, a first combined laser light source of the present invention comprises a plurality of semiconductor lasers arranged in a predetermined direction and an elliptical or oval core cross section on the incident side. And a laser beam emitted from each of the plurality of semiconductor lasers and a single optical fiber arranged so that the major axis of the ellipse or ellipse faces the predetermined direction, And a condensing optical system for coupling the beam to the incident end of the optical fiber.
In this combined laser light source, the semiconductor laser may be composed of a multi-cavity laser having a plurality of light emitting points arranged in a predetermined direction.

In the first combined laser light source of the present invention, the laser beam emitted from each of the plurality of semiconductor lasers arranged in a predetermined direction is condensed by a condensing optical system, and is formed into an ellipse or an ellipse. It is coupled to the incident end of one optical fiber that has a core cross section and is arranged so that the major axis of the ellipse or ellipse faces a predetermined direction (that is, the arrangement direction of the semiconductor lasers). The incident laser beam is emitted from the emission end of the optical fiber.

In a combined laser light source that combines a plurality of laser beams using an optical fiber, the core diameter and numerical aperture (NA) of the optical fibers to be arranged are arranged in order to further increase the brightness.
However, if the core diameter or NA is reduced, the number of laser beams that can be coupled and combined decreases, and the output from each optical fiber decreases.

On the other hand, in the first combined laser light source according to the present invention, the core cross section of the optical fiber is elliptical or oval, and the long axis direction thereof is directed to the arrangement direction of the semiconductor lasers. Since laser beams emitted from more semiconductor lasers can be coupled to the incident end of one optical fiber, the output of the combined laser light source can be increased without reducing the number of laser beams that can be combined. In addition, high brightness can be achieved. Further, the laser beam emitted from each of the plurality of semiconductor lasers is condensed and coupled to an optical fiber, and can be easily manufactured.

In order to achieve the above object, a second combined laser light source of the present invention includes a single multicavity laser having a plurality of light emitting points arranged in a predetermined direction, an ellipse or an ellipse. A single optical fiber having a core cross section on the incident side and arranged so that the major axis of the ellipse or ellipse faces the predetermined direction, and a laser beam emitted from each of the plurality of light emitting points are collected. And a condensing optical system for coupling the converging beam to the incident end of the optical fiber.

In the second combined laser light source of the present invention, the laser beam emitted from each of a plurality of light emitting points arranged in a predetermined direction of a single multicavity laser is condensed by a condensing optical system. The elliptical or oval core cross section is coupled to the incident end of one optical fiber arranged so that the major axis of the oval or oval is directed in a predetermined direction (that is, the light emitting point arrangement direction). The The incident laser beam is emitted from the emission end of the optical fiber.

In this combined laser light source as well, more light emission is obtained by arranging the core cross section of the optical fiber to be oval or oval and the long axis direction thereof being directed to the arrangement direction of the emission points of the multicavity laser. Since the laser beam emitted from the point can be coupled to the incident end of one optical fiber, the output power and the brightness of the combined laser light source can be increased without reducing the number of laser beams that can be combined. Can be achieved. Moreover, it has a very simple configuration and is easy to manufacture.

In the first and second combined laser light sources, the ratio of the major axis to the minor axis of the ellipse or ellipse of the core cross section is
It is preferable that the ratio of the major axis to the minor axis of the focused beam is substantially equal. Since the laser beam emitted from the semiconductor laser has different divergence angles in the stripe direction and the active layer direction,
The shape of the focused beam is an ellipse or an ellipse. By making the ratio between the major axis and the minor axis of the condensed beam and the ratio between the major axis and the minor axis of the core cross section substantially equal, the coupling efficiency of the condensed beam to the optical fiber can be increased.

In order to achieve the above object, the fiber array light source of the present invention comprises a plurality of the combined laser light sources of the present invention, and each of the emission ends of the optical fibers has the major axis of the ellipse or ellipse. They are arranged in an array so as to face the arrangement direction of the emission ends.

In a fiber array light source in which the emission ends of optical fibers are arranged in an array, a high-power laser beam is 1
The light is emitted in a state of being arranged in a two-dimensional array.
The laser beam emitted in such an aligned state is incident on each modulation unit of the spatial light modulation element in which the modulation unit is arranged one-dimensionally or two-dimensionally, and is efficiently modulated for image exposure or the like. be able to.

Also, by arranging the emission ends of the optical fibers in an array so that the long axis of the ellipse or ellipse faces the arrangement direction of the emission ends, the direction orthogonal to the arrangement direction of the emission ends of the fiber array light source Can be made small, and even when applied to a light source of an exposure apparatus, a deep depth of focus can be obtained.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. (First Embodiment) As shown in FIG. 1, a combined laser light source according to an embodiment of the present invention has a plurality of (for example, seven) chip-shaped horizontal elements arranged and fixed on a heat block 10. Multimode or single mode GaN-based semiconductor lasers LD1, LD2, LD3, LD4, LD5, LD6
And LD7 and collimator lenses 11, 1 provided corresponding to each of the GaN-based semiconductor lasers LD1 to LD7.
2, 13, 14, 15, 16, and 17, one condenser lens 20, one multimode optical fiber 30,
It is composed of In this example, the collimator lens 11
-17 and the condensing lens 20 constitute a condensing optical system, and the condensing optical system and the multimode optical fiber 30 constitute a multiplexing optical system.

The GaN semiconductor lasers LD1 to LD7 are
All oscillation wavelengths are common (for example, 405 nm), and the maximum output is also common (for example, 1 for a multimode laser).
00 mW and 30 mW for a single mode laser). The GaN-based semiconductor lasers LD1 to LD7 have a wavelength range of 350 nm to 450 nm and the above 40
A laser having an oscillation wavelength other than 5 nm can be used.

The multimode optical fiber 30 is shown in FIG.
As shown in (A), the cross section of the core 30a has an elliptical shape, and the major axis direction of the ellipse substantially coincides with the arrangement direction (direction parallel to the active layer) of the GaN-based semiconductor lasers LD1 to LD7. Are arranged as follows. The laser beam emitted in an aligned state from the GaN-based semiconductor lasers LD1 to LD7 arranged in a predetermined direction is collected by the condenser lens 20, and the beam cross section of this condensed beam also has a long laser arrangement direction. It has an elliptical shape in the axial direction. Therefore, the cross-sectional shape of the core 30a is not a circle but an ellipse whose major axis direction is the laser arrangement direction, so that a larger number of laser beams can be condensed and combined.

As shown in FIG. 2B, the diameter of the core 30a having an elliptical cross section with respect to the clad diameter a of the multimode optical fiber 30 includes a major axis b and a minor axis c. In order to improve the coupling efficiency of the condensed beam to the multimode optical fiber 30 by the condenser lens 20, the ratio of the major axis b to the minor axis c of the core 30a is the ratio of the major axis to the minor axis of the condensed beam. It is preferable that they are substantially equal.

The multimode optical fiber 30 may be any of a step index type optical fiber, a graded index type optical fiber, and a composite type optical fiber. For example, a step index type optical fiber manufactured by Mitsubishi Cable Industries, Ltd. can be used. In the present embodiment, the multimode optical fiber 30 is a step index type optical fiber and has a cladding diameter a = 60 μm.
m, core major axis b = 25 μm, core minor axis c = 15 μm, N
A = 0.2.

As shown in FIG. 3, FIG. 4 and FIG.
The optical elements constituting the above-described combined laser light source are accommodated in a box-shaped package 40 having an upper opening, thereby constituting a laser module. The package 40 includes a package lid 41 manufactured so as to close the opening thereof, and a sealing gas is introduced after the deaeration process, so that the package 40
By closing the opening with the package lid 41, the combined laser light source is hermetically sealed in a closed space (sealing space) formed by the package 40 and the package lid 41.

A base plate 42 is fixed to the bottom surface of the package 40. On the top surface of the base plate 42, the heat block 10, a condensing lens holder 45 for holding the condensing lens 20, and multimode light are provided. A fiber holder 46 that holds the incident end of the fiber 30 is attached. Further, a collimator lens holder 44 is attached to the side surface of the heat block 10, and the collimator lenses 11 to 17 are held.

The exit end of the multimode optical fiber 30 is drawn out of the package through an opening formed in the wall surface of the package 40. In addition, an opening is formed in the lateral wall surface of the package 40, and wiring 4 for supplying a driving current to the GaN-based semiconductor lasers LD1 to LD7 through the opening.
7 is pulled out of the package.

In FIG. 4, in order to avoid complication of the drawing, only the GaN semiconductor laser LD 7 among the plurality of GaN semiconductor lasers is numbered, and only the collimator lens 17 among the plurality of collimator lenses. It is numbered.

FIG. 5 shows the collimator lenses 11-17.
The front shape of the attachment part is shown. Each of the collimator lenses 11 to 17 is formed in a shape obtained by cutting a region including the optical axis of a circular lens having an aspherical surface into a long and narrow plane. This elongated collimator lens can be formed, for example, by molding resin or optical glass. Collimator lens 1
1 to 17 are GaN-based semiconductor lasers LD1 to LD1 in the length direction.
The light emitting points of the LD 7 are closely arranged in the light emitting point arrangement direction so as to be orthogonal to the light emitting point arrangement direction (left and right direction in FIG. 5).

On the other hand, GaN semiconductor lasers LD1 to LD.
7 includes an active layer having a light emission width of 1 μm, and each has a divergence angle of, for example, 10 in a direction parallel to and perpendicular to the active layer.
Lasers that emit laser beams B1 to B7 in the state of ° and 30 °, respectively, are used. These GaN-based semiconductor lasers LD1 to LD7 are arranged so that the light emitting points are arranged in a line in a direction parallel to the active layer.

Therefore, the laser beams B1 to B7 emitted from the respective light emitting points are spread with the direction in which the divergence angle is large coincides with the length direction with respect to the elongated collimator lenses 11 to 17 as described above. Incident light enters in a state in which the direction with a small angle coincides with the width direction (direction perpendicular to the length direction). That is, the collimator lenses 11 to 17 have a width of 1.1 mm and a length of 4.6 mm, and the horizontal and vertical beam diameters of the laser beams B1 to B7 incident thereon are 0.9 mm and 2. 6 mm. Also,
Each of the collimator lenses 11 to 17 has a focal length f ₁ =
3mm, NA = 0.6, Lens arrangement pitch = 1.25m
m.

The condensing lens 20 is obtained by cutting a region including the optical axis of a circular lens having an aspherical surface into an elongated shape in a parallel plane, and extending in the direction in which the collimator lenses 11 to 17 are arranged, that is, in the horizontal direction and perpendicular thereto. It is formed in a short shape. The condenser lens 20 has a focal length f ₂ = 23 m.
m, NA = 0.2. This condensing lens 20 is also formed by molding resin or optical glass, for example.

Next, the operation of the combined laser light source will be described.

Laser beams B1, B2, emitted from each of the GaN-based semiconductor lasers LD1 to LD7 in a divergent light state.
Each of B3, B4, B5, B6, and B7 is collimated by the corresponding collimator lenses 11-17.
The collimated laser beams B <b> 1 to B <b> 7 are collected by the condenser lens 20 and converge on the incident end face of the core 30 a of the multimode optical fiber 30.

The laser beams B1 to B7 condensed as described above by the condenser lens 20 enter the core 30a of the multimode optical fiber 30, propagate through the optical fiber, and become one laser beam B. The light is combined and emitted from the multimode optical fiber 30. In each laser module, when the coupling efficiency of the laser beams B1 to B7 to the multimode optical fiber 30 is 0.9 and the outputs of the GaN-based semiconductor lasers LD1 to LD7 are 100 mW, the output is 630 mW (= 100 mW × 0 .9 × 7) combined laser beam B can be obtained.

The condensing beam by the condensing lens 20 has an elliptical shape in which the beam cross section has a major axis = 16.5 μm and a minor axis = 10 μm. Therefore, when this focused beam is to be coupled to a circular multimode optical fiber having a core cross section of 15 μm in diameter, a part of the focused beam is kicked. Multimode optical fiber 3 used in the present embodiment
In the case of 0, the minor axis c of the core 30a is 15 μm, but the major axis b is 25 μm, so that the condensed beam can be efficiently combined. Also, GaN-based semiconductor lasers LD1 to LD1
The mounting tolerance of the LD 7 and the condenser lens 20 can be expanded.

The laser module described above is
As shown in FIG. 6, the output end portions of the multimode optical fiber 30 are arranged in a one-dimensional array, and are sandwiched and fixed between two support plates 65 having a flat surface. A fiber array light source that emits an ultraviolet laser beam B from each of them can be configured. For example, by arranging 16 multimode optical fibers 30 that emit a combined laser beam with an output of 630 mW, a high output of about 10 W can be realized. The light density is also 5W /
mm {= 10 W / (125 μm × 16)}. Further, the energy efficiency can be as high as about 20%, which is equivalent to the light emission efficiency of the GaN-based semiconductor laser.

The multimode optical fibers 30 are arranged so that the major axis direction of the ellipse is substantially parallel to the arrangement direction of the multimode optical fibers 30. From this fiber array light source, high-power laser beams are emitted in a line-aligned state, and each multimode optical fiber 30 is arranged so that the major axis of the ellipse of the core section faces the arrangement direction of the emission end. Therefore, the beam diameter in the direction orthogonal to the arrangement direction of the emission ends of the fiber array light source can be reduced. Therefore, even when applied to a light source of an exposure apparatus, a deep depth of focus can be obtained.

As described above, in the combined laser light source according to the present embodiment, the core cross section of the optical fiber to which the condensed beam is coupled is the major axis direction that is the same laser array direction as the beam cross section of the condensed beam. Since the elliptical shape is used, it is possible to increase the output and the brightness of the combined laser light source without reducing the number of laser beams to be condensed. Further, the laser beam emitted from each of the plurality of semiconductor lasers is condensed and coupled to an optical fiber, and can be easily manufactured.

Also, a fiber array light source using this combined laser light source can be easily manufactured with high output and is low in cost.

(Second Embodiment) A combined laser light source according to a second embodiment is a multi-light source having a plurality of light emitting points instead of combining laser beams from a plurality of chip-shaped semiconductor lasers. A laser beam from each light emitting point of the cavity laser is multiplexed. As shown in FIG. 7, the combined laser light source includes a multi-cavity laser 110 having a plurality of (for example, three) light emitting points 110a, 1
The multi-mode optical fiber 30 and a lens 20 as an optical system for allowing the laser beams B respectively emitted from the plurality of light emitting points 110a to enter the core 30a of the multi-mode optical fiber 30 are configured. The same components as those of the combined laser light source according to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

The multicavity laser 110 can be composed of, for example, a GaN laser diode having an oscillation wavelength of 405 nm. Further, the number of light emitting points is not limited to three.

In the above configuration, each of the laser beams B emitted from each of the plurality of light emitting points 110 a of the multicavity laser 110 is collected by the condenser lens 20 and enters the core 30 a of the multimode optical fiber 30. . The laser light incident on the core 30a propagates through the optical fiber, is combined into one, and is emitted.

A plurality of light emitting points 110a of the multi-cavity laser 110 are arranged in parallel within a width substantially equal to the core long diameter (25 μm) of the multi-mode optical fiber 30, and
By using a convex lens having a focal length substantially equal to the core diameter of the multimode optical fiber 30 or a rod lens that collimates the emitted beam from the multicavity laser 110 only in a plane perpendicular to the active layer as the condenser lens 20. , Laser beam B multimode optical fiber 30
The coupling efficiency to can be increased.

Since the core cross section of the multimode optical fiber 30 has an elliptical shape, a plurality of light emitting points 110a are within a width substantially equal to the major axis of the multimode optical fiber 30.
In the multi-cavity laser 110 in which the plurality of light emitting points 110a are arranged side by side, the pitch between the plurality of light emitting points 110a becomes relatively large. And re-stabilization is possible. And a high output is obtained. For example, a combined laser beam B having an output of about 300 mW can be obtained by using the multi-cavity laser 110 whose output from each light emitting point 110a is 100 mW.

It should be noted that the first laser light source is used to
Similarly to the embodiment, a laser module or a fiber array light source device in which the emission end portion of the optical fiber 30 is pulled out from the casing can be configured.

In this case, the condensed beam by the condenser lens 20 has a condensed beam diameter of major axis = 25 μm and minor axis = 1.
It has an elliptical shape of 0 μm. Therefore, when this focused beam is to be coupled to a circular multimode optical fiber having a core cross section of 15 μm in diameter, a part of the focused beam is kicked. As described above, the multimode optical fiber 30 used in the present embodiment has a core 30a having a short diameter c of 15 μm, but has a long diameter b of 25 μm, so that the condensed beam can be efficiently combined.

As described above, the combined laser light source according to the present embodiment collects laser beams from a plurality of emission points of a single multicavity laser and couples them to an optical fiber. As in the first embodiment, since the core cross section of the optical fiber has an elliptical shape, it is possible to increase the output and the brightness of the combined laser light source without reducing the number of converging laser beams. it can. Moreover, it has a very simple configuration and is easy to manufacture.

In the first and second embodiments, the clad diameter = 60 μm, the core long diameter = 25 μm, and the core short diameter = 1.
Although the example using the multi-mode optical fiber 30 of 5 μm and NA = 0.2 has been described, the cross-sectional shape of the optical fiber is not limited to this. Alternatively, a multimode optical fiber having a large clad diameter, which is coaxially coupled with an optical fiber having a length of 1 to 30 cm and a small clad diameter, may be used at the tip of the laser light emission side. For example, cladding diameter =
125 μm, core major axis = 25 μm, core minor axis = 15 μm
The incident side end face of the optical fiber with clad diameter = 60 μm, core long diameter = 25 μm, core short diameter = 15 μm, NA = 0.2 was fused to the output side end face of the multimode optical fiber with m and NA = 0.2. An optical fiber can be used.

[0051]

According to the present invention, there is provided a combined laser light source that can be easily manufactured and can achieve high output and high brightness.
In addition, a high-power and low-cost fiber array light source is provided.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration of a combined laser light source according to a first embodiment.

FIG. 2 is a diagram showing a configuration of a multimode optical fiber.

FIG. 3 is a plan view showing a configuration of a laser module.

4 is a side view showing the configuration of the laser module shown in FIG. 3. FIG.

5 is a partial side view showing the configuration of the laser module shown in FIG. 3. FIG.

6 is a perspective view of a fiber array light source using a plurality of laser modules shown in FIG. 3. FIG.

FIG. 7 is a plan view showing a configuration of a combined laser light source according to a second embodiment.

[Explanation of symbols]

10 Heat block 11-17 Collimator lens 20 Condensing lens 30 Multimode optical fiber 30a core 40 packages 41 Package lid LD1-LD7 GaN semiconductor laser 110 Multicavity laser 110a luminous point

Continued front page    F-term (reference) 2H037 AA04 BA03 BA32 CA12 CA20                       CA21 DA03 DA04 DA05 DA06                       DA16                 5F073 AA89 AB02 AB04 AB27 AB28                       BA09 CA02 EA24 EA29 FA07                       FA08 FA23 FA30

Claims (5)

[Claims] 1. A plurality of semiconductor lasers arranged in a predetermined direction, an elliptical or oval core cross section on the incident side, and arranged such that a major axis of the elliptical or oval faces the predetermined direction A combined laser comprising: an optical fiber; and a condensing optical system that condenses a laser beam emitted from each of the plurality of semiconductor lasers and couples the condensed beam to an incident end of the optical fiber. light source. 2. The combined laser light source according to claim 1, wherein the semiconductor laser is a multicavity laser having a plurality of light emitting points arranged in a predetermined direction. 3. A single multi-cavity laser having a plurality of light emitting points arranged in a predetermined direction, an elliptical or oval core cross section on the incident side, and the major axis of the elliptical or oval is A single optical fiber arranged to face a predetermined direction, and a condensing optics for condensing the laser beam emitted from each of the plurality of light emitting points and coupling the condensed beam to the incident end of the optical fiber And a combined laser light source comprising: 4. The ratio of the major axis to the minor axis of the ellipse or ellipse is
2. The ratio of the major axis to the minor axis of the focused beam is approximately equal to claim 1.
4. The combined laser light source according to any one of items 1 to 3. 5. A plurality of the combined laser light sources according to claim 1, wherein each of the emission ends of the optical fiber is arranged in a direction in which the major axis of the ellipse or oval is the emission end. Fiber array light sources arranged in an array so as to face.