WO2022149358A1

WO2022149358A1 - Laser device, underwater optical wireless communication device, and laser machining device

Info

Publication number: WO2022149358A1
Application number: PCT/JP2021/042518
Authority: WO
Inventors: 隼規坂本
Original assignee: 株式会社島津製作所
Priority date: 2021-01-06
Filing date: 2021-11-19
Publication date: 2022-07-14
Also published as: JPWO2022149358A1

Abstract

One fiber (7) has a part which becomes one end. At least two fibers (13) have parts which respectively become other ends. A fiber combiner (8) connects a part opposite to the part of the fiber (7) which becomes one end and parts opposite to the parts of the fibers (13) which become the respective other ends. The fiber combiner (8) is configured such that cores of the fibers (13) are arrayed so as to fit into a core of the fiber (7) having a polygonal cross-sectional shape, and the core of the fiber (7) and the cores of the fibers (13) are fusion-spliced.

Description

Laser equipment, underwater optical wireless communication equipment and laser processing equipment

This disclosure relates to a laser device, an underwater optical wireless communication device, and a laser processing device.

Conventionally, a laser device that emits a laser beam from a laser light source via a fiber is known. As a fiber used in such a laser device, Patent Document 1 describes a rectangular fiber having a mode scramble effect fused and connected to a non-rectangular fiber. In Patent Document 1, it is possible to obtain a laser beam having a more uniform beam profile than a non-rectangular fiber. Further, Patent Document 2 describes a plurality of fibers bundled at a tapered portion and coupled to one fiber. Patent Document 2 proposes a method of constructing a fiber combiner using polygonal fibers and suppressing heat generation at the combiner coupling portion.

A fiber combiner is an optical component manufactured by bundling a plurality of fibers, melting and stretching them, and fusing them with one fiber. Laser light input to a plurality of fibers can be emitted from one fiber, and is utilized in applications such as efficiently collecting light sources for clad excitation of a fiber laser. Further, in the fiber combiner, laser light input in the opposite direction, that is, one fiber, can be emitted from a plurality of fibers.

Japanese Unexamined Patent Publication No. 2009-198680 Japanese Patent Application Laid-Open No. 2015-040992

At this time, the beam profile of the laser beam emitted from the fiber has a correlation with the beam profile of the laser beam incident on the fiber. That is, the laser light incident from a high NA (numerical aperture) having a large incident angle has a high NA component at the time of fiber exit, and the laser light incident from a low NA having a small incident angle has a low NA component at the time of fiber exit. Tend. As the laser beam propagates through the fiber, this tendency is alleviated and homogenized. However, when a sufficient fiber length cannot be secured or when the fiber core diameter is large, it tends to be difficult to make them uniform.

In a fiber-coupled laser device that combines each laser beam emitted from a plurality of laser light sources into one fiber, the incident NA of the laser beam is limited by the distance between the emission points between the laser light sources. When the fibers of this laser device are connected to a junction such as a fiber combiner and branched by multiple fibers, the output of each fiber varies and is not uniformed thereafter, resulting in emission from each fiber. There is a problem that the output of the laser beam to be generated varies.

The present disclosure has been made in view of the actual circumstances, and one purpose of the present disclosure is to provide a laser device capable of suppressing variations in the output of laser light emitted from a plurality of fibers.

A laser device according to an aspect of the present disclosure includes a plurality of laser light sources, an optical transmission unit, and one or more condensing optical elements. The plurality of laser light sources emit laser light. The optical transmission unit receives the laser light emitted from the plurality of laser light sources from one end and emits the laser light from the other end. The one or more condensing optical elements condense the laser light emitted from the plurality of laser light sources and make it incident on one end of the optical transmission unit. The optical transmission unit includes a first fiber, a second fiber, and a junction. The first fiber has a portion that is one and is one end. The second fiber has two or more portions that are the ends of the other. The junction connects a portion opposite to one end of the first fiber and a portion opposite to the other end of the plurality of second fibers. The joints are arranged so that the cores of the plurality of second fibers are contained in the cores of the first fiber having a polygonal cross-sectional shape, and the cores of the first fiber and the cores of the plurality of second fibers are fused. It is connected.

The underwater optical wireless communication device according to another aspect of the present disclosure includes a laser device. The underwater optical wireless communication device is used underwater and transmits a signal by a laser beam to perform communication.

A laser processing device according to another aspect of the present disclosure includes a laser device. The laser processing device simultaneously emits laser light in a plurality of directions to perform laser welding.

According to the present disclosure, it is possible to suppress variations in the output of laser light emitted from the side of a plurality of fibers. As a result, the laser beam is made uniform, which is useful for a device that emits the laser beam in multiple directions. For example, in an underwater optical communication device, in order to reduce a non-communicable area, a laser light source capable of radiating a laser beam having a uniform power and beam profile in the entire underwater space is desired. The wireless communication device can efficiently fill the space. In a laser processing apparatus, for example, it is possible to irradiate a circumference having a uniform beam profile and a laser beam having a laser beam power at intervals of 120 degrees, which is useful for welding cylindrical parts and the like.

It is a figure which shows the laser apparatus which concerns on 1st Embodiment. It is a figure which shows the laser housing. It is a figure which shows LD. It is a figure which shows the output state of the underwater optical wireless communication device. It is a figure which shows the output state of the underwater optical wireless communication device. It is a figure which shows an example of a fiber combiner. It is a figure which shows the state which arranged a plurality of LDs. It is a figure which shows the incident angle and the laser beam intensity. It is a figure which shows the sectional view of the fiber. It is a figure which shows the sectional view of the fiber. It is a figure which shows the sectional view of the fiber. It is a figure which shows the sectional view of the fiber. It is a figure which shows the sectional view of the fiber. It is a figure which shows the sectional view of the fiber. It is a figure which shows the sectional view of the fiber. It is a figure which shows the laser housing which concerns on 2nd Embodiment. It is a figure which shows the fiber which concerns on 4th Embodiment. It is a figure which shows the output state of the laser processing apparatus which concerns on 5th Embodiment. It is a figure which shows the output state of the laser processing apparatus which concerns on 5th Embodiment. It is a figure which shows the laser housing which concerns on the modification.

Hereinafter, each embodiment will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals and the description thereof will not be repeated.

[First Embodiment]
Hereinafter, the underwater optical wireless communication device 51 and the laser device 50 according to the first embodiment will be described. In the first embodiment, the underwater optical wireless communication device 51 is configured to include the laser device 50.

FIG. 1 is a diagram showing a laser device 50 according to the first embodiment. FIG. 2 is a diagram showing a laser housing 100. FIG. 3 is a diagram showing LD40. 4A and 4B are diagrams showing an output state of the underwater optical wireless communication device 51.

As shown in FIG. 1, the laser device 50 includes a laser housing 100 and an optical transmission unit 30.
The optical transmission unit 30 includes a fiber 7, a plurality of fibers 13, and a fiber combiner 8 as a junction. In the present embodiment, the laser light emitted from the laser housing 100 is emitted as a plurality of laser beams 11 via the optical transmission unit 30.

As shown in FIG. 2, the laser housing 100 includes a plurality of high-power laser diodes (hereinafter, simply referred to as “LD”) 40 and one or more condensing optical elements as a laser light source. Each of the plurality of LD40s emits a laser beam.

In the present embodiment, one or more condensing optical elements are composed of a collimating lens 2, a beam expander 5, and a condensing lens 6. With these condensing optical elements, the laser light emitted from the plurality of LD40s is condensed and incident on one end of the optical transmission unit 30 (left side in the figure).

The multiple LD40s have LD chips contained in a Φ9.0 package and have high heat dissipation performance. As shown in FIG. 3, the LD40 is housed in the holder 1a. The collimating lens 2 is housed in the holder 2a. By finely adjusting the positions of the LD40 and the collimated lens 2, collimated light having a desired beam profile can be obtained. The positional relationship between the plurality of LD40s and the collimating lens 2 is fixed by YAG laser welding between the holder 1a and the holder 2a via the connecting pipe 3.

Returning to FIG. 2, the collimated plurality of laser beams 4 reduce the beam diameter by the beam expander 5. Next, the plurality of laser beams 4 are focused on the end face of the fiber 7 by the condenser lens 6 and coupled to the fiber core.

The laser housing 100 is composed of a plurality of LD40s and one or more condensing optical elements (collimating lens 2, beam expander 5, condensing lens 6). That is, the laser device 50 includes a plurality of LD40s, one or more condensing optical elements, and an optical transmission unit 30.

Returning to FIG. 1, the optical transmission unit 30 incidents the laser light emitted from the plurality of LD40s from one end and emits the laser light from the other end. Here, in FIG. 1, "one end" refers to the left end of the optical transmission unit 30 (the left end of the fiber 7), and the other end is the right end of the optical transmission unit 30. Refers to a portion (the right end of the fiber 13).

The fiber 7 has a portion that is one and becomes one end (left end). The plurality of fibers 13 have a portion that is two or more and becomes the other end portion (right end portion).

The fiber combiner 8 has a portion opposite to one end of the fiber 7 (the right end of the fiber 7) and a portion opposite the other end of the plurality of fibers 13 (fiber). Connect with the left end of 13).

Specifically, the fiber 7 is connected to the plurality of fibers 10 inside the fiber combiner 8 via the fusion splicer 9. The fiber 7 has a length of, for example, about 30 m. The fiber combiner 8 has a plurality of fibers 10 combined into one end by heating with a burner or the like.

If draw stress is applied during melt heating, the core and clad of the plurality of fibers 10 can be tapered. Flatten the end of the fiber thinned on the taper. In this way, it is possible to fuse this with the right end of the fiber 7. The plurality of fibers 10 may be used as the fiber combiner 8.

A part of the laser beam leaks at the fusion part of the fiber combiner 8 due to the fusion loss. When a high-power laser beam is input to the fiber combiner 8, there is a risk of damage due to heat generation. Therefore, the fiber combiner 8 is housed in a metal package. Efficient heat dissipation can be achieved by fixing the metal package to the heat sink.

The laser light propagated to the plurality of fibers 10 is emitted as the laser light 11 from the plurality of fibers 10. By adjusting the emission direction of the plurality of fibers 10, the laser beam 11 can be emitted in any direction.

The cross section of the fiber 7 is as shown in the fiber cross section 7b. The cross section of the plurality of fibers 10 is as shown in the plurality of fiber cross sections 10b. These cross sections will be described later with reference to FIGS. 8A to 8G.

As shown in FIG. 4A, the underwater optical wireless communication device 51 includes a laser device 50. The underwater optical wireless communication device 51 is used underwater and transmits a signal by a laser beam to perform communication.

The underwater optical wireless communication device 51 is a mobile body that moves underwater. The underwater optical wireless communication device 51 communicates with, for example, an optical communication device fixed in the sea. The underwater optical wireless communication device 51 includes an AUV (Autonomous Underwater Vehicle).

For example, when the underwater optical wireless communication device 51 receives the communication light emitted from the optical communication device, optical communication is performed between the optical communication device and the underwater optical wireless communication device 51, and the underwater optical wireless communication device 51 is performed. By receiving the communication light emitted from the optical communication device, the optical communication device can perform optical communication between the underwater optical wireless communication device 51 and the optical communication device.

Electromagnetic waves have a large amount of attenuation in water and a short propagation distance. Therefore, for wireless communication underwater, sound waves with a long propagation distance are generally used. On the other hand, among electromagnetic waves, visible light has a relatively small amount of attenuation in water. Therefore, by receiving the digitally modulated light emitted from one device by the photodiode or photomultiplier tube built in the other device, wireless communication is performed between the two devices.

The end of the fiber 13 is cleaved and smoothed. Then, as shown in FIG. 4B, the emission angles of the fibers 13 are adjusted and arranged.

In this way, visible laser light can be emitted in multiple directions. In this example, it is composed of three fibers 13, and emits

laser beams

41, 42, and 43, respectively. The communicable distance is L, and communication is possible within the emission range of the illustrated

laser beams

41, 42, and 43.

In this way, since the laser light can be emitted in all directions, communication can be performed with the position adjustment of the transmitter and the receiver minimized as long as the visible light is not attenuated. That is, since the emission range of the laser beam is wide, the degree of freedom in the position of the receiver with respect to the transmitter is high.

FIG. 5 is a diagram showing an example of a fiber combiner. In the present embodiment, as shown in FIG. 1, an example in which one laser beam is divided into a plurality of laser beams is shown. However, the present invention is not limited to this, and a plurality of laser beams may be aggregated into one laser beam. In this case, the one corresponding to the fiber 7 corresponds to the plurality of fibers 14, and the one corresponding to the plurality of fibers 13 corresponds to the fiber 17. Further, the fiber combiner 8 may be something like the fiber combiner 16.

In the example of FIG. 1, the diameter of the plurality of fibers 10 was configured to be constant. On the other hand, in the example of FIG. 5, the diameter of the plurality of fibers 15 is configured to become smaller as it approaches the fiber 17. The fibers of the fiber combiner are bundled, melted, stretched, adjusted to an outer diameter or core diameter close to the fiber to be connected, and then fused.

FIG. 6 is a diagram showing a state in which a plurality of LD40s are arranged. As shown in FIG. 6, in the present embodiment, the LD module 20 in which nine LD40s (LD40a to LD40i) are arranged is configured. In the LD module 20, the LD 40s are arranged in a tile shape with an interval D of 3 × 3. Specifically, LD40a, LD40b, LD40c are arranged from the left in the upper part, LD40d, LD40e, LD40f are arranged from the left in the middle part, and LD40g, LD40h, LD40i are arranged from the left in the lower part.

Since the LD40 inside the laser housing 100 is housed in a Φ9.0 package and is housed in the holder 1a, there is a lower limit to the arrangement interval depending on the dimensions of the holder 1a.

In this example, the LD40s are arranged in a tile shape having a spacing D1 of 3 × 3, and the optical axis of the central LD40e and the optical axis of the fiber 7 are aligned with each other. At this time, the distances from the central LD40e to the four LD40s (LD40b, d, f, h) adjacent to each other in the vertical and horizontal directions are approximately D1. Further, the distance to four LD40s (LD40a, c, g, i) adjacent in the diagonal direction is approximately 2 ^1/2 × D1 (= D2).

From this, each of the collimated plurality of laser beams 4 has one central component, four components D1 away from the center, and a component 2 ^1/2 × D1 (= D2) away from the center in the condenser lens 6. There will be four. Therefore, the distance from the center of the condenser lens 6 is concentrated on the components of 0, D1, 2, ^1/2 D1. Due to such circumstances, the plurality of laser beams 4 incident on the fiber 7 are concentrated on a part of NA (numerical aperture).

FIG. 7 is a diagram showing an incident angle and a laser beam intensity. As described above, as a result of the distance from the center of the condenser lens 6 being concentrated on the components of 0, D1, ^{2 1/2} D1, the relationship between the incident angle and the laser beam intensity is as shown in FIG. The distribution is such that the type + center becomes a little stronger. The light intensity in the central portion is increased by the central LD40e, and the donut-shaped light intensity is increased by the eight LD40s around the LD40e.

As described above, in the LD module 20, the laser light intensity varies due to the restriction of the arrangement of the plurality of LD40s in the product design. Further, even if there is only one LD40, the intensity distribution will be a mountain-shaped distribution with a strong central intensity, and the laser beam intensity will also vary.

Generally, the incident NA of the laser beam incident on the fiber has a correlation with the emitted NA. Therefore, the laser beam intensity with respect to the emission angle from the fiber has a far field pattern that reflects the incident NA.

When the fiber 7 and the one port side of the fiber combiner 8 were fused and connected, the intensity of the laser light emitted from the multiple port sides of the fiber combiner 8 was observed to vary. This is because the modes inside the fiber are not uniform.

Hereinafter, we propose a method of making the mode inside the fiber 7 uniform to reduce the intensity variation of the laser light emitted from the plurality of ports of the fiber combiner 8.

As described with reference to FIG. 1, the cross section of the fiber 7 is as shown in the fiber cross section 7b. The cross section of the plurality of fibers 10 is as shown in the plurality of fiber cross sections 10b.

As described above, the fiber has a polygonal core cross-sectional structure, and the fiber combiner 8 and the fiber 7 using the fiber having a circular core cross-sectional structure are fused and connected.

The fiber combiner 8 is arranged so that the cores of the plurality of fibers 13 are accommodated in the cores of the fiber 7 having a polygonal cross section, and the cores of the fiber 7 and the cores of the plurality of fibers 13 are fused and connected. be. Further, the cross-sectional area of the core of the fiber 7 is larger than the cross-sectional area of any one of the plurality of fibers 13. Hereinafter, a specific description will be given.

8A to 8G are views showing a cross-sectional view of the fiber. As shown in FIG. 8A, in this example, in the fiber cross section 7a of the fiber 7, the cross section shape of the core 71a is circular. As shown in FIG. 8B, in this example, in the fiber cross section 7b of the fiber 7, the cross section shape of the core 71b is rectangular. As shown in FIG. 8C, in this example, in the fiber cross section 7c of the fiber 7, the cross section shape of the core 71c is a hexagon.

As shown in FIG. 8D, in this example, in the plurality of fiber cross sections 10a of the plurality of fibers 10, there are seven cores 101a, and the cross-sectional shape thereof is circular. Further, in the fiber combiner 8, seven cores 101a are arranged so as to fit in the core 71a of the fiber 7. Specifically, when the fusion connection is performed, the seven cores 101a are contained in the circle of the cores 71a. In the present embodiment, the core diameter of the plurality of fibers 10 and the core diameter of the plurality of fibers 13 are the same. When the ones of FIGS. 8A and 8D are used, the fiber combiner 8 is arranged so that the cores of the plurality of fibers 13 are contained in the cores 71a of the fiber 7, and the cores 71a of the fiber 7 and the cores of the plurality of fibers 13 are arranged. Will be fused and connected. By doing so, the intensity of the laser beam does not vary at the fused and connected portions.

As shown in FIG. 8E, in this example, in the plurality of fiber cross sections 10b of the plurality of fibers 10, there are nine cores 101b, and the cross section shape thereof is circular. Further, in the fiber combiner 8, nine cores 101b are arranged so as to fit in the core 71b of the fiber 7. Specifically, when the fusion connection is performed, the nine cores 101b are contained in the rectangle of the core 71b. In the present embodiment, the core diameter of the plurality of fibers 10 and the core diameter of the plurality of fibers 13 are the same. When the ones of FIGS. 8B and 8E are used, the fiber combiner 8 is arranged so that the cores of the plurality of fibers 13 are contained in the cores 71b of the fiber 7, and the cores 71b of the fiber 7 and the cores of the plurality of fibers 13 are arranged. Will be fused and connected. By doing so, the intensity of the laser beam does not vary at the fused and connected portions.

As shown in FIG. 8F, in this example, in the plurality of fiber cross sections 10c of the plurality of fibers 10, there are 13 cores 101c, and the cross section shape thereof is circular. Further, in the

fiber combiner

8, 13 cores 101c are arranged so as to fit in the core 71c of the fiber 7.

As shown in FIG. 8G, in this example, in the plurality of fiber cross sections 10d of the plurality of fibers 10, there are 19 cores 101d, and the cross section shape thereof is circular. Further, in the fiber combiner 8, 19 cores 101c are arranged so as to fit in the core 71a of the fiber 7. The cross-sectional shape of the plurality of fibers 10 is not limited to a circular shape, but may be a polygonal shape.

Here, in comparison between FIGS. 8A and 8D, the diameter of the core 71a of the fiber 7 is 400 μm, the diameter of the core 101a of the plurality of fibers 10 is 105 μm, and the diameter of the core of the fiber 13 is 105 μm. That is, the diameter (cross-sectional area) of the core 71a of the fiber 7 is larger than the diameter (cross-sectional area) of the core of the fiber 13.

When the fiber combiner is configured as shown in FIG. 5, for example, the diameter of the core 71a of the fiber 7 is set to 200 μm, the diameter of the core 101a of the plurality of fibers 10 is changed to 50 to 105 μm, and the fiber 13 is used. The diameter of the core can be 105 μm. In an underwater optical communication device as in the present embodiment, in order to maintain the water pressure performance, the larger the fiber diameter, the higher the manufacturing cost of the fiber. Therefore, it is desirable to make the fiber diameter as small as possible.

Similarly, in the comparison between FIGS. 8B and 8E, the cross-sectional area of the core 71b of the fiber 7 is larger than the cross-sectional area of the core of the fiber 13. Also, in comparison between FIGS. 8C and 8F, the cross-sectional area of the core 71c of the fiber 7 is larger than the cross-sectional area of the core of the fiber 13.

When the core cross-sectional structure of the fiber 7 is polygonal, the fiber 7 has a mode scramble effect. Therefore, the laser beam emitted from the fiber 7 is more likely to be uniformized as compared with the case where the core cross-sectional structure of the fiber 7 is circular.

Therefore, in the present embodiment, the optical transmission unit 30 is configured by the combination of FIGS. 8B and 8E. 8A to 8G illustrate that the core cross-sectional structure of the fiber 7 is rectangular or hexagonal, but any fiber having a mode scramble effect may be used.

As described above, the fiber 7 having a polygonal cross-sectional shape having a mode scramble effect is used, and the fiber combiner 8 is set so that the cores of the plurality of fibers 13 are contained in the core of the fiber 7 having a polygonal cross-sectional shape. Since they are arranged, it is possible to suppress variations in the output of the laser beam emitted from the plurality of fiber sides of the fiber combiner 8. This makes it possible to emit a laser beam having a uniform beam profile in multiple directions, which is useful for a device that emits laser light in multiple directions.

In the underwater optical communication device, in order to reduce the communication impossible area, a laser light source capable of radiating a laser beam having a uniform power and beam profile in the entire underwater space is desired. The device can efficiently fill the space. As described above, in the present embodiment, it is possible to suppress the variation in the output of the plurality of emitted laser beams for the device that divides and uses one laser beam into a plurality of parts.

[Second Embodiment]
Next, the laser apparatus 50 according to the second embodiment will be described. In the second embodiment, a configuration will be described in which the mode inside the fiber 7 is made uniform to further reduce the intensity variation of the laser beam emitted from the plurality of ports of the fiber combiner 8.

In the first embodiment described with reference to FIGS. 1 to 8G, in the laser apparatus 50, the laser housing 100 has a plurality of LD40s, and one or more condensing optical elements (collimating lens 2, beam expander 5, and condensing). It was equipped with a lens 6).

In the laser apparatus 50 according to the second embodiment, the laser housing 100 further includes a diffractive optical element 12. Other configurations are the same as those of the first embodiment, and the underwater optical wireless communication device 51 includes the laser device 50 according to the second embodiment.

In the first embodiment, the cross section of the fiber 7 is defined as the fiber cross section 7b, and the cross section of the plurality of fibers 10 is described as the plurality of fiber cross sections 10b. It may be a combination of a fiber cross section 7c and a plurality of fiber cross sections 10c, or may be another combination.

FIG. 9 is a diagram showing a laser housing according to the second embodiment. In this example, as shown in FIG. 9, the diffractive optical element 12 is arranged between the beam expander 5 and the condenser lens 6.

In the second embodiment, a two-dimensional transmission type diffractive optical element (diffraction) designed as a homogenizer in which the intensity distribution becomes uniform at the time of laser focusing when the designated condenser lens 6 is used before being incident on the condenser lens 6. An optical element 12) is arranged.

When applied when the beam profile of the collimated laser light before the condenser lens 6 is, for example, the donut mode (beam intensity distribution 31), the beam profile is shaped into the collimated laser light having a top hat shape (beam intensity distribution 32). can do. Uniform laser light can be fiber-coupled.

In this way, the beam profile of the laser beam incident on one end of the optical transmission unit 30 is focused in the shape of a top hat. Specifically, the beam profile is shaped into a top hat shape by the beam homogenizer optical system.

In the present embodiment, the beam profile is shaped into a top hat shape by using the diffractive optical element 12 as described in FIG. The beam homogenizer optical system may be shaped into a top hat shape by using a DOE (Diffractive Optical Elements) beam shaper, or may be shaped into a top hat shape by using a fly-eye lens. It may be shaped into a top hat shape.

[Third Embodiment]
In the first embodiment and the second embodiment, the laser beam incident on the fiber 7 is configured to be incident on the fiber combiner 8 from the fiber 7 without going out of the fiber.

On the other hand, in the third embodiment, the fiber 7 is divided into two fibers. Then, the laser light is once emitted from the fiber 7 before being incident on the fiber combiner 8, and the emitted laser light is condensed by the condensing optical element and then incident on the fiber 7 again. Other configurations are the same as those of the first embodiment and the second embodiment.

For example, in the configuration of FIG. 1, the configuration is such that the middle of the path of the fiber 7 is divided. Then, a condensing optical element is arranged between the divided left fiber 7 and the right fiber 7.

As in the first embodiment, the condensing optical element may be composed of a plurality of condensing optical elements (collimating lens 2, beam expander 5, condensing lens 6, etc.), or one condensing optical element. It may be configured.

The laser light emitted from the laser housing 100 is incident on the fiber 7. After that, the laser light once emitted from the fiber 7 (left side) is condensed by the condensing optical element and is incident on the fiber 7 (right side) again. After that, the laser beam is incident on the fiber combiner 8 from the fiber 7. The cross-sectional shape of the fiber 7 divided into left and right may be a rectangular shape or a polygon such as the core 71b, or one may be a circular shape such as the core 71a.

[Fourth Embodiment]
In the first to third embodiments, the fiber 7 is arranged in a straight line or an arbitrary curve. On the other hand, in the fourth embodiment, the fiber 7 is configured to be bent a plurality of times in an S shape. Other configurations are the same as those of the first embodiment to the third embodiment.

FIG. 10 is a diagram showing a fiber according to a fourth embodiment. As shown in FIG. 10, the fiber 7 is bent so as to draw a curve of an angle θ with a radius of curvature R, and then, on the opposite side, the fiber 7 is bent so as to draw a curve of an angle θ with a radius of curvature R. The fiber 7 is bent in an S shape. By repeating this, the fiber 7 has a configuration in which the fiber 7 is bent a plurality of times in an S shape.

By bending the fiber 7 in this way, the higher-order mode can be converted into the radiation mode. At this time, the laser beam in the radiation mode hits the coating or the like arranged outside the fiber, is absorbed, and generates heat. Therefore, the periphery is covered with a metal housing to absorb the leaked laser beam. Clad mode In order to actively extract light, contacting an object with a refractive index higher than that of the clad with the clad increases the extraction efficiency. Even if the fiber is repeatedly bent in the S order, the extraction efficiency is improved.

[Fifth Embodiment]
In the first to fourth embodiments, the underwater optical wireless communication device 51 has been described as an example of the device provided with the laser device 50. However, the device provided with the laser device 50 is not limited to this. In the fifth embodiment, the laser processing device 52 will be illustrated and described as an example of the device including the laser device 50. Other configurations are the same as those of the first to fourth embodiments.

11A and 11B are diagrams showing the output state of the laser processing apparatus according to the fifth embodiment. As shown in FIGS. 11A and 11B, the laser processing device 52 includes a laser device 50 and a laser output unit 62. Although this figure is a schematic view, the laser processing apparatus 52 includes a laser apparatus 50 as shown in FIGS. 1 to 3, and is assumed to correspond to the plurality of fibers 13 in FIG. 1 and has 3 on the output side. It is equipped with a book fiber.

Then,

laser beams

63, 64, and 65 are emitted from each fiber, respectively. In this way, the laser processing device 52 simultaneously emits laser light in a plurality of directions to perform laser welding.

When fixing a cylindrical part in laser machining, for example, as shown in FIG. 6, a method of irradiating laser light at the same timing so as to be symmetrical at intervals of 120 degrees is known. At this time, the change during welding becomes large due to the variation in power. By using this method, it is possible to suppress variations in the outputs of the emitted

laser beams

63, 64, 65.

It should be noted that the output side is not limited to the one provided with three fibers, and a plurality of fibers may be arranged at equal intervals. However, if the number of lines is increased too much, the output per line will decrease, so it is necessary to divide the number so that laser processing can be performed.

As described above, the fiber 7 having a polygonal cross-sectional shape having a mode scramble effect is used, and the fiber combiner 8 is set so that the cores of the plurality of fibers 13 are contained in the core of the fiber 7 having a polygonal cross-sectional shape. Since they are arranged, it is possible to suppress variations in the output of the laser beam emitted from the plurality of fiber sides of the fiber combiner 8. This makes it possible to emit a laser beam having a uniform beam profile in multiple directions, which is useful for a device that emits laser light in multiple directions. In a laser processing apparatus, for example, it is possible to irradiate a circumference having a uniform beam profile and a laser beam having a laser beam power at intervals of 120 degrees, which is useful for welding cylindrical parts and the like.

[Modification example]
FIG. 12 is a diagram showing a laser housing according to a modified example. In the second embodiment, as shown in FIG. 9, the diffractive optical element 12 is arranged between the beam expander 5 and the condenser lens 6. However, the present invention is not limited to this, and the diffractive optical element 12 may be arranged between the condenser lens 6 and the fiber 7.

By arranging the two-dimensional transmission type diffraction grating (diffraction optical element 12) after the condenser lens 6, that is, in the middle of convergence, the beam profile at the time of focusing can be made uniform (beam intensity distribution 31). Is the beam intensity distribution 32). Alternatively, it can be realized by eliminating the condenser lens 6 and arranging a diffractive optical element designed to collect light when a collimated laser beam is incident.

[Aspect]
It will be understood by those skilled in the art that the above-described exemplary embodiments are specific examples of the following embodiments.

(1) The laser device according to one aspect includes a plurality of laser light sources, an optical transmission unit, and one or more condensing optical elements. The plurality of laser light sources emit laser light. The optical transmission unit receives the laser light emitted from the plurality of laser light sources from one end and emits the laser light from the other end. The one or more condensing optical elements condense the laser light emitted from the plurality of laser light sources and make it incident on one end of the optical transmission unit. The optical transmission unit includes a first fiber, a plurality of second fibers, and a junction. The first fiber has a portion that is one and is one end. The second fiber has two or more portions that are the ends of the other. The junction connects a portion of the first fiber opposite to one end of the first fiber and a portion of the plurality of second fibers opposite to the other end of the fiber. The joints are arranged so that the cores of the plurality of second fibers are contained in the cores of the first fiber having a polygonal cross-sectional shape, and the cores of the first fiber and the cores of the plurality of second fibers are fused. It is connected.

According to the laser apparatus according to the first item, the first fiber having a polygonal cross-sectional shape having a mode scramble effect is used, and the joint portion has a plurality of first fibers in the core of the first fiber having a polygonal cross-sectional shape. Since the cores of the two fibers are arranged so as to fit into each other, it is possible to suppress variations in the output of laser light emitted from a plurality of fiber sides of the fiber combiner (joint portion). As a result, the laser beam is made uniform, which is useful for a device that emits the laser beam in multiple directions. For example, in an underwater optical communication device, in order to reduce a non-communicable area, a laser light source capable of radiating a laser beam having a uniform power and beam profile in the entire underwater space is desired. The wireless communication device can efficiently fill the space. In a laser processing apparatus, for example, it is possible to irradiate a circumference having a uniform beam profile and a laser beam having a laser beam power at intervals of 120 degrees, which is useful for welding cylindrical parts and the like.

(Clause 2) In the laser apparatus according to paragraph 1, the cross-sectional area of the core of the first fiber is larger than the cross-sectional area of any one of the plurality of second fibers.

According to the laser device according to the second item, in a laser device to which a fiber combiner is applied to divide one laser light into a plurality of laser lights and emit the laser light, the laser light emitted from a plurality of fiber sides of the fiber combiner. The variation of the output of is suppressed.

(Clause 3) In the laser apparatus according to the first or second paragraph, the beam profile of the laser light incident on one end of the optical transmission unit is focused in the shape of a top hat.

According to the laser device according to the third item, since the intensity of the laser light incident on one end of the optical transmission unit is made uniform, the output of the laser light emitted from the plurality of fiber sides of the fiber combiner is made uniform. Variation can be suppressed.

(Clause 4) In the laser apparatus according to any one of the third paragraphs, the beam profile is shaped into a top hat shape by the beam homogenizer optical system.

According to the laser apparatus according to the fourth item, since the intensity of the laser light incident on one end of the optical transmission unit is made uniform, the output of the laser light emitted from the plurality of fiber sides of the fiber combiner is made uniform. Variation can be suppressed.

(Clause 5) In the laser device according to the third item, the beam profile is shaped into a top hat shape by using a diffractive optical element.

According to the laser apparatus according to the fifth item, since the intensity of the laser light incident on one end of the optical transmission unit is made uniform, the output of the laser light emitted from the plurality of fiber sides of the fiber combiner is made uniform. Variation can be suppressed.

(Clause 6) In the laser apparatus according to any one of the items 1 to 5, laser light is emitted from the first fiber and the emitted laser light is condensed before being incident on the junction. The light is collected by an optical element and then incident again on the first fiber.

According to the analytical laser apparatus according to the sixth item, since the laser light is collected again by the condensing optical element, it is possible to suppress the variation in the output of the laser light emitted from the plurality of fiber sides of the fiber combiner.

(Clause 7) In the laser apparatus according to any one of the items 1 to 6, the first fiber is bent a plurality of times in an S shape.

According to the analytical laser apparatus according to the seventh item, since the higher-order mode can be converted into the radiation mode, the variation in the output of the laser light emitted from the plurality of fiber sides of the fiber combiner can be suppressed.

(Item 8) The underwater optical wireless communication device according to one aspect includes the laser device according to any one of items 1 to 7. The underwater optical wireless communication device is used underwater and transmits a signal by a laser beam to perform communication.

According to the underwater optical wireless communication device described in item 8, variation in the output of laser light emitted from a plurality of fiber sides of the fiber combiner (joint portion) can be suppressed. As a result, the laser beam is made uniform, which is useful for a device that emits the laser beam in multiple directions. In the underwater optical communication device, in order to reduce the communication impossible area, a laser light source capable of radiating a laser beam having a uniform power and beam profile in the entire underwater space is desired. The device can efficiently fill the space.

(Section 9) The laser processing apparatus according to one aspect includes the laser apparatus according to any one of paragraphs 1 to 7. The laser processing device simultaneously emits laser light in a plurality of directions to perform laser welding.

According to the laser processing apparatus described in Section 9, variations in the output of laser light emitted from a plurality of fiber sides of a fiber combiner (joint portion) can be suppressed. As a result, the laser beam is made uniform, which is useful for a device that emits the laser beam in multiple directions. In the laser processing apparatus, for example, it is possible to irradiate a circumference having a uniform beam profile and a laser beam having a laser beam power at intervals of 120 degrees, which is useful for welding cylindrical parts and the like.

The embodiments disclosed this time should be considered to be exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope of the claims.

1a, 2a holder, 2 collimating lens, 3 continuous pipe, 4 laser light, 5 beam expander, 6 condensing lens, 7 fiber, 7a, 7b, 7c fiber cross section, 8 fiber combiner, 9 fusion splicer, 10 multiple fibers, 10a, 10b, 10c, 10d Multiple fiber cross sections, 11 Multiple laser beams, 12 Diffraction optical elements, 13 fibers, 14, 17 fibers, 15 Multiple fibers, 16 Fiber combiners, 20 LD modules, 31, 32 Beam intensity distribution, 40 LD , 40a, 40b, 40c, 40d, 40e, 40f, 40g, 40h, 40i LD, 41, 42, 43 laser light, 50 laser device, 51 underwater optical wireless communication device, 52 laser processing device, 61 laser output unit, 63 , 64,65 laser beam, 71a, 71b, 71c core, 100 laser housing, 101a, 101b, 101c, 101d core. It was

Claims

Multiple laser light sources that emit laser light,
An optical transmission unit that incidents the laser light emitted from the plurality of laser light sources from one end and emits the laser light from the other end.
It comprises one or more condensing optical elements that condense the laser light emitted from the plurality of laser light sources and condense the laser light to be incident on the one end of the optical transmission unit.
The optical transmission unit is
A first fiber having a portion that is one end of the fiber,
A second fiber having two or more and having a portion to be the other end portion,
Includes a junction that connects a portion of the first fiber that is the opposite end of the one end and a portion of the second fiber that is opposite to the other end of the second fiber.
The joints are arranged so that the plurality of cores of the second fiber are contained in the core of the first fiber having a polygonal cross-sectional shape, and the core of the first fiber and the core of the plurality of second fibers are arranged. A laser device that is fused and connected to the core.
The laser device according to claim 1, wherein the cross-sectional area of the core of the first fiber is larger than the cross-sectional area of any one of the plurality of the second fibers.
The laser device according to claim 1 or 2, wherein the beam profile of the laser beam incident on the one end of the optical transmission unit is focused in the shape of a top hat.
The laser device according to claim 3, wherein the beam profile is shaped into the top hat shape by a beam homogenizer optical system.
The laser device according to claim 3, wherein the beam profile is shaped into the top hat shape by using a diffractive optical element.
1 The laser device according to any one of claims 5.
The laser device according to any one of claims 1 to 6, wherein the first fiber is bent a plurality of times in an S shape.
The laser apparatus according to any one of claims 1 to 7 is provided.
An underwater optical wireless communication device that is used in water and transmits a signal by the laser beam to perform communication.
The laser apparatus according to any one of claims 1 to 7 is provided.
A laser processing device that simultaneously emits the laser light in a plurality of directions for laser welding.