JP2010103159A - Fiber laser oscillation device, and na conversion optical system for fiber laser - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fiber laser oscillation device which can be made compact furthermore, and to provide an NA conversion optical system for the fiber laser which makes the fiber laser oscillation device compact furthermore. <P>SOLUTION: An optical fiber F2 for fiber laser is wound circularly with such a diameter as the pumping light L1 can be confined inside. A pumping light source module 10 is arranged near the central part of the optical fiber for fiber laser thus wound, and the pumping light L1 is emitted to traverse the circle of the optical fiber for fiber laser. An NA conversion optical system 30 for the fiber laser is constituted of a selective reflection mirror 35 which reflects the pumping light L1 but transmits the laser light L2, a first lens 31 and a second lens 32, wherein the selective reflection mirror is arranged at a predetermined angle so that the traveling direction of the pumping light is tangent to the optical fiber for fiber laser which is wound circularly, and the first and second lenses are arranged between the selective reflection mirror and the end face of the optical fiber for fiber laser. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fiber laser oscillation apparatus and a fiber laser NA conversion optical system that obtains laser light generated by being incident on a fiber laser optical fiber and excited in the fiber laser optical fiber.

Conventionally, various fiber laser oscillations that use laser light, such as a semiconductor laser, as pumping light, enter the fiber laser optical fiber, take out the laser light generated in the fiber laser optical fiber, and use it for processing. A device has been proposed.
For example, in the prior art described in Patent Document 1, as shown in FIG. 4, the excitation light L1 emitted from the semiconductor laser 101 operated by the laser power source 102 and converted into parallel light by a condensing means (not shown) The light is transmitted through the dichroic mirror 301 and condensed by the lens 302, and is incident from one end face (on the connector F2A side) of the optical fiber F2 for fiber laser. Laser light generated in the fiber laser optical fiber F2 is emitted from one end face and the other end face of the fiber laser optical fiber F2. The laser light emitted from one end face (connector F2A side) is returned into the fiber laser optical fiber F2 by the dichroic mirror 301 that transmits the excitation light L1 and reflects the laser light L2. The optical fiber F2 for fiber laser is wound with a predetermined diameter capable of confining incident excitation light without leaking outside. The laser light emitted from the other end face (connector F2C side) is converted into parallel light by the lens 311 and then passes through a dichroic mirror 312 that reflects part of the laser light L2 and transmits the rest. The laser beams are taken out by branch mirrors 321, 322, and 323 (branch mirror 323 has a reflectivity of 100%) that branches a part or all of the laser light at a predetermined branch ratio. Each of the extracted laser beams L2 is collected by lenses 324, 325, and 326, respectively, is incident on each of the transmission optical fibers F3, and is used for laser processing or the like of the workpiece W. In FIG. 4, the description of the laser absorber that absorbs the laser beam L2 and the folding mirror that is disposed between the dichroic mirror 312 and the branch mirror 321 and reflects the laser beam L2 in the direction of the laser absorber is omitted. Yes.
JP 2007-190560 A

When the system described in Patent Document 1 shown in FIG. 4 is housed in a housing as shown in the example of FIG. 1A as a fiber laser oscillation device, the area for housing the excitation light source module 100 and the excitation light L1 are The area for accommodating the pumping light guide module 300 that guides the fiber laser optical fiber F2, the area for accommodating the wound fiber laser optical fiber F2, and the generated laser light L2 are guided to the transmission optical fiber F3. The area for accommodating the laser light guide module 310 to be used is necessary, and the fiber laser oscillation device becomes very large.
The present invention was devised in view of these points, and includes a fiber laser oscillation device that enables further miniaturization, and an NA conversion optical system for a fiber laser for further miniaturizing the fiber laser oscillation device. The issue is to provide.

As means for solving the above-mentioned problems, the first invention of the present invention is a fiber laser oscillation device as described in claim 1.
The fiber laser oscillation device according to claim 1, when the excitation light is incident, emits the excited laser light from the end face, and emits the excitation light incident on the fiber laser optical fiber. A pumping light source module and the pumping light are collected and incident on the end face of the fiber laser optical fiber, and the laser beam emitted from the end face of the fiber laser optical fiber is focused on a preset laser focusing position. And a fiber laser NA conversion optical system.
The optical fiber for a fiber laser is wound in a circular shape with a diameter capable of confining incident excitation light inside, and an end surface thereof is directed in a direction of a tangent in contact with the circle, and the excitation light source module Is disposed near the center of the wound fiber laser optical fiber, emits the excitation light so as to cross the circle of the fiber laser optical fiber, and the fiber laser NA conversion optical system is And a selective reflection mirror that reflects the excitation light and transmits the laser light, a first lens, and a second lens.
The selective reflection mirror is disposed on an extension of the emission direction of the excitation light emitted from the excitation light source module, and the traveling direction of the excitation light reflected by the selective reflection mirror is wound in a circular shape. The fiber laser optical fiber is disposed at a predetermined angle so as to be in contact with the circle, and the end face of the fiber laser optical fiber faces the traveling direction of the excitation light reflected by the selective reflection mirror Are arranged as follows.
Further, between the selective reflection mirror and the end face of the fiber laser optical fiber, the first lens and the second lens transmit the excitation light reflected by the selective reflection mirror through the first lens. The laser light emitted from the end face of the fiber laser optical fiber is arranged so as to be transmitted through the second lens and condensed on the end face of the fiber laser optical fiber after being converted into parallel light. Is transmitted through the second lens and converted into parallel light, then transmitted through the first lens and the selective reflection mirror, and set at a position that becomes a focal length of the first lens. It is focused on.

According to a second aspect of the present invention, there is provided a fiber laser oscillation device as set forth in the second aspect.
The fiber laser oscillation device according to claim 2 emits an optical fiber for a fiber laser that emits the excited laser light from an end face when the excitation light is incident, and an excitation light that enters the optical fiber for the fiber laser. A pumping light source module and the pumping light are collected and incident on the end face of the fiber laser optical fiber, and the laser beam emitted from the end face of the fiber laser optical fiber is focused on a preset laser focusing position. And a fiber laser NA conversion optical system.
The optical fiber for a fiber laser is wound in a circular shape with a diameter capable of confining incident excitation light inside, and an end surface thereof is directed in a direction of a tangent in contact with the circle, and the excitation light source module Is disposed near the center of the wound fiber laser optical fiber, emits the excitation light so as to cross the circle of the fiber laser optical fiber, and the fiber laser NA conversion optical system is And a selective reflection mirror that reflects the excitation light and transmits the laser light, a first lens, a second lens, and a third lens.
The selective reflection mirror is disposed on an extension of the emission direction of the excitation light emitted from the excitation light source module, and the traveling direction of the excitation light reflected by the selective reflection mirror is wound in a circular shape. The fiber laser optical fiber is disposed at a predetermined angle so as to be in contact with the circle, and the end face of the fiber laser optical fiber faces the traveling direction of the excitation light reflected by the selective reflection mirror Are arranged as follows.
Further, the first lens is disposed between the excitation light source module and the selective reflection mirror so as to convert the excitation light emitted from the excitation light source into parallel light, and the selective reflection mirror and the selective reflection mirror Between the end face of the fiber laser optical fiber, the second lens causes the parallel excitation light reflected by the selective reflection mirror to pass through the second lens and collect on the end face of the fiber laser optical fiber. It is arranged so as to be emitted, and is on an extension of the emission direction of the laser beam emitted from the fiber laser optical fiber and at a position after the laser beam has passed through the second lens and the selective reflection mirror. The third lens is disposed, and the laser beam emitted from the end face of the fiber laser optical fiber passes through the second lens and is converted into parallel light, and then the selective reaction is performed. Is transmitted through the mirror and the third lens, it is focused on the set the laser light converging position to the position where the focal length of the third lens.

According to a third aspect of the present invention, there is provided a fiber laser oscillation device as set forth in the third aspect.
The fiber laser oscillation device according to claim 3 is the fiber laser oscillation device according to claim 1, wherein the laser focusing position is selected in a path between the selective reflection mirror and the laser focusing position. A third lens that is brought close to the reflection mirror is provided.

According to a fourth aspect of the present invention, there is provided a fiber laser oscillation device as set forth in the fourth aspect.
The fiber laser oscillation device according to claim 4 is the fiber laser oscillation device according to any one of claims 1 to 3, and further reflects the laser light so that the laser focusing position is in an arbitrary direction. A laser reflection mirror for conversion is provided, and the laser reflection mirror is disposed on an extension of the emission direction of the laser light emitted from the fiber laser optical fiber and at a position after passing through the selective reflection mirror.

According to a fifth aspect of the present invention, there is provided a fiber laser NA conversion optical system according to the fifth aspect.
The fiber laser NA conversion optical system according to claim 5, wherein the pumping light emitted from the pumping light source module is incident on an end face of the fiber laser optical fiber and pumped by the pumping light. This is a fiber laser NA conversion optical system that condenses laser light emitted from an optical fiber at a preset laser condensing position.
The NA conversion optical system for fiber laser reflects the excitation light emitted from the excitation light source module and traveling in the first direction, and changes the traveling direction of the excitation light in a second direction different from the first direction. A selective reflection mirror that transmits laser light emitted in the third direction opposite to the second direction from the end face of the fiber laser optical fiber disposed on the extension in the second direction; and the selective reflection mirror; A first lens disposed between an end face of the optical fiber for the fiber laser and converting the excitation light reflected by the selective reflection mirror into parallel light; and the first lens and the optical fiber for the fiber laser. A second lens disposed between the end face and condensing the excitation light converted into the parallel light and entering the end face of the fiber laser optical fiber, the second lens, Laser light emitted from the end face of the optical fiber for fiber laser is converted into parallel light, and the first lens is a laser set on the extension in the third direction by converting the laser light converted into the parallel light. Condensed at the condensing position.

The sixth aspect of the present invention is a fiber laser NA conversion optical system according to the sixth aspect.
7. The fiber laser NA conversion optical system according to claim 6, wherein the pumping light emitted from the pumping light source module is incident on an end face of the fiber laser optical fiber and pumped by the pumping light. This is a fiber laser NA conversion optical system that condenses laser light emitted from an optical fiber at a preset laser condensing position.
The NA conversion optical system for fiber laser reflects the excitation light emitted from the excitation light source module and traveling in the first direction, and changes the traveling direction of the excitation light in a second direction different from the first direction. A selective reflection mirror that transmits laser light emitted in the third direction opposite to the second direction from the end face of the fiber laser optical fiber disposed on the extension in the second direction; and the excitation light source module; Between the selective reflection mirror and a first lens that converts the excitation light emitted from the excitation light source module into parallel light, and between the selective reflection mirror and the end face of the fiber laser optical fiber. The pumping light that is arranged and converted into the parallel light is collected and incident on the end face of the optical fiber for the fiber laser and the end face of the optical fiber for the fiber laser. The second lens for converting the emitted laser light into parallel light, and the laser light emitted from the optical fiber for fiber laser on the extension in the third direction passed through the second lens and the selective reflection mirror. A third lens disposed at a later position and condensing the laser light at a laser condensing position set on the extension in the third direction.

  According to the fiber laser oscillation device of claim 1, the fiber laser oscillation device is configured by housing the excitation light source module, the wound fiber laser optical fiber, and the fiber laser NA conversion optical system in the casing. In this case, since the area for accommodating the excitation light source module and the area for accommodating the wound fiber laser optical fiber can be overlapped, the size can be further reduced.

  According to the fiber laser oscillation device of claim 2, as in the case of claim 1, the pumping light source module, the wound fiber laser optical fiber, and the fiber laser NA conversion optical system are disposed in the casing. In the case where the fiber laser oscillation device is configured in the same manner, the area for accommodating the pumping light source module and the area for accommodating the wound fiber laser optical fiber can be overlapped, so that the size can be further reduced.

  According to the fiber laser oscillation device of claim 3, for example, the incident end face of the transmission optical fiber that guides the laser beam to the processing portion of the workpiece by the laser beam being incident is disposed at the laser condensing position, for example. In this case, since the laser focusing position is brought close to the selective reflection mirror, the fiber laser oscillation device can be further downsized.

  According to the fiber laser oscillation device of claim 4, the laser condensing position can be set without being limited to the emission direction of the laser beam emitted from the end face of the fiber laser optical fiber. It is convenient to make the device more compact.

  Further, according to the NA conversion optical system for a fiber laser described in claim 5, it is possible to realize the fiber laser oscillation device described in claim 1, which can be further miniaturized.

  Further, according to the NA conversion optical system for a fiber laser described in claim 6, it is possible to realize the fiber laser oscillation device described in claim 2, which can be further downsized.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a fiber laser oscillation device 1 of the present invention, FIG. 1 (A) shows an example of an external appearance (perspective view), and FIG. 1 (B) shows an internal structure (plan view). Example).

[First Embodiment (FIGS. 1 and 2)]
As shown in the example of FIG. 1A, the fiber laser oscillation device 1 described in the first embodiment is provided with an operation state display means H, various operation switches SW, etc. on the front panel. From the rear side, a transmission optical fiber F3 to which the generated laser light is guided is attached. The transmission optical fiber F3 can be attached to and detached from a laser condensing position to be described later, and may be omitted from the fiber laser oscillation device 1.
Note that the fiber laser oscillation device 1 shown in FIG. 1A has a structure described below, so that the fiber laser oscillation device 1 is further miniaturized and can be accommodated in a rack of a general specified size.

Next, the internal structure of the fiber laser oscillation device 1 will be described with reference to FIG.
The housing of the fiber laser oscillation device 1 has a pump light source module 10 that emits pump light L1 incident on the fiber laser optical fiber F2, and a core portion doped with a rare earth element such as Yb (ytterbium). A fiber laser optical fiber F2 that generates laser light when excited by the incident excitation light, a fiber laser NA conversion optical system 30 composed of a mirror, a lens, and the like, a power source 40, a control device 50, and the like. Contained.
For example, the excitation light source module 10 guides each laser beam emitted from each light emitting portion of the semiconductor laser array LD from one end surface of the excitation light optical fiber F1, and uses the other end surface of the excitation light optical fiber F1. Laser light used as excitation light L1 is emitted from the bundled binding part F1A.

The optical fiber F2 for a fiber laser is wound in a circular shape with a diameter capable of confining the excitation light L1 incident from one end face (the end face on the connector F2A side in the example of FIG. 1B). Thus, the one end face is directed in the direction of a tangent line that is in contact with the circle wound in a circular shape. The other end face of the fiber laser optical fiber F2 is provided with laser reflecting means F2B that reflects the laser light that is excited and emitted from the other end face and returns it to the fiber laser optical fiber F2. . Thereby, the laser beam L2 excited in the fiber laser optical fiber F2 is emitted from one end face on the connector F2A side.
The excitation light source module 10 is arranged near the center of the wound fiber laser optical fiber F2 (such as above or below the center of the fiber laser optical fiber F2) and wound in a circular shape. The excitation light L1 is emitted so as to cross the circle of the fiber laser optical fiber F2.

As shown in FIG. 2, the fiber laser NA conversion optical system 30 includes a selective reflection mirror 35 that reflects the excitation light L1 and transmits the laser light L2 emitted from the fiber laser optical fiber F2, and a first lens 31. A second lens 32, a third lens 33, and a laser reflecting mirror 36 that reflects the laser light L2 in the direction of the laser focusing position P. In the first embodiment shown in FIGS. 1 and 2, the third lens 33 and the laser reflecting mirror 36 may be omitted.
The selective reflection mirror 35 is, for example, a dichroic mirror that reflects light having the wavelength of the excitation light L1 and transmits light having the wavelength of the laser light L2, and is configured to transmit the excitation light L1 emitted from the binding portion F1A of the excitation light source module 10. The traveling direction of the excitation light L1 reflected by the selective reflection mirror 35 is arranged on the extension of the emission direction (corresponding to the first direction), and the fiber laser optical fiber F2 wound in a circular shape has the above-described direction. It is set at a predetermined angle so as to be in contact with the circle.
One end face of the fiber laser optical fiber F2 (the end face on the connector F2A side) is disposed so as to face the traveling direction (corresponding to the second direction) of the excitation light L1 reflected by the selective reflection mirror 35.

  Between the selective reflection mirror 35 and one end face of the fiber laser optical fiber F2, the excitation light L1 reflected by the selective reflection mirror 35 passes through the first lens 31 and is converted into parallel light. The first lens 31 and the second lens 32 are disposed so as to pass through the two lenses and be condensed on one end face of the fiber laser optical fiber F2. That is, the focal length of the first lens 31 is the distance from the first lens 31 to the selective reflection mirror 35 (the distance of the optical axis), and the distance from the selective reflection mirror 35 to the emission position of the excitation light source module 10 (of the optical axis). Distance). The focal length of the second lens 32 is the distance (the distance of the optical axis) from the second lens 32 to one end face of the fiber laser optical fiber F2.

The laser light L2 emitted from one end face of the fiber laser optical fiber F2 is transmitted through the second lens 32 and converted into parallel light, and then transmitted through the first lens 31 and the selective reflection mirror 35. The laser light L2 is condensed at the position of the focal length of the first lens 31 on the extension of the emission direction (corresponding to the third direction). In the example of FIGS. 1B and 2, the laser reflection mirror 36 that reflects the laser light L <b> 2 is disposed on the extension of the emission direction of the laser light L <b> 2, and the laser light L <b> 2 is directed in the direction of the laser focusing position P. The direction of travel has been changed. Further, laser focusing is performed in the path between the selective reflection mirror 35 and the laser focusing position P (between the selective reflection mirror 35 and the laser reflecting mirror 36 or between the laser reflecting mirror 36 and the laser focusing position P). A third lens 33 that moves the position P closer to the selective reflection mirror 35 is disposed. At the laser condensing position P, one end face of the transmission optical fiber F3 is disposed. F3A is a connector for fixing the position of the end face of the transmission optical fiber F3 to the laser condensing position P.
Since the laser reflection mirror 36 can set the direction and position of the laser condensing position P without being limited to the emission direction of the laser light L2, it is convenient for further downsizing the fiber laser oscillation device.
Further, since the laser condensing position P is brought close to the selective reflection mirror 35 by the third lens 33, the fiber laser oscillation device 1 can be further downsized.

● [Second Embodiment (FIG. 3)]
Next, a second embodiment of the fiber laser oscillator 1 and the fiber laser NA conversion optical system 30 will be described with reference to FIG. In the second embodiment, the configuration of the fiber laser NA conversion optical system 30 is different from that of the first embodiment, and the configuration and arrangement of the excitation light source module 10 and the fiber laser optical fiber F2 are the same. Therefore, this difference will be described.

As shown in FIG. 3, the fiber laser NA conversion optical system 30 in the second embodiment reflects the excitation light L1 and transmits the laser light L2 emitted from the fiber laser optical fiber F2. 35, a first lens 31, a second lens 32, a third lens 33, and a laser reflecting mirror 36 that reflects the laser light L2 in the direction of the laser focusing position P. In the second embodiment shown in FIG. 3, the laser reflecting mirror 36 may be omitted.
As in the first embodiment, the selective reflection mirror 35 is a dichroic mirror that reflects light having the wavelength of the excitation light L1 and transmits light having the wavelength of the laser light L2, for example, and binding the excitation light source module 10 together. The excitation light L1 emitted from the portion F1A is arranged on the extension of the emission direction (corresponding to the first direction), and the traveling direction of the excitation light L1 reflected by the selective reflection mirror 35 is circularly wound. The fiber laser optical fiber F2 is arranged at a predetermined angle so as to contact the circle.
One end surface of the fiber laser optical fiber F2 (the end surface on the connector F2A side) is the traveling direction of the excitation light L1 reflected by the selective reflection mirror 35 (corresponding to the second direction), as in the first embodiment. It is arranged to face each other.

Between the binding portion F1A of the excitation light source module 10 and the selective reflection mirror 35, a first lens 31 that converts the excitation light L1 emitted from the binding portion F1A (emission portion) into parallel light is disposed.
Between the selective reflection mirror 35 and one end face of the fiber laser optical fiber F2, the parallel excitation light L1 reflected by the selective reflection mirror 35 is collected on one end face of the fiber laser optical fiber F2. The second lens 32 is disposed so as to be illuminated. That is, the focal length of the first lens 31 is the distance from the binding part F1A to the first lens 31 (the distance of the optical axis). The focal length of the second lens 32 is the distance (the distance of the optical axis) from the second lens 32 to one end face of the fiber laser optical fiber F2.

Then, the laser light L2 emitted from one end face of the fiber laser optical fiber F2 passes through the second lens 32 and is converted into parallel light, and then passes through the selective reflection mirror 35 to emit the laser light L2. The laser beam L2 passes through the second lens 32 and the third lens 33 disposed at a position after passing through the selective reflection mirror 35 on the extension of the direction (corresponding to the third direction), and the third lens 33 It is condensed at the position of the focal length. In the example of FIG. 3, the laser reflection mirror 36 that reflects the laser beam L2 is disposed on the extension of the emission direction of the laser beam L2, and the traveling direction of the laser beam L2 is changed in the direction of the laser focusing position P. ing. Further, a third lens is disposed in the path between the selective reflection mirror 35 and the laser condensing position P (between the selective reflection mirror 35 and the laser reflecting mirror 36 or between the laser reflecting mirror 36 and the laser condensing position P). 33 should just be arrange | positioned. At the laser condensing position P, one end face of the transmission optical fiber F3 is disposed. F3A is a connector for fixing the position of the end face of the transmission optical fiber F3 to the laser condensing position P.
Since the laser reflection mirror 36 can set the direction and position of the laser condensing position P without being limited to the emission direction of the laser light L2, it is convenient for further downsizing the fiber laser oscillation device.

As described above, the fiber laser oscillation device 1 described in the present embodiment provides a plurality of functions to the first lens 31 (first embodiment) and the second lens 32 (first and second embodiments). By providing (collimation of excitation light, condensing of excitation light, collimation of laser light, condensing of laser light), a fiber laser of excitation light with a smaller number of parts compared to the conventional configuration shown in FIG. The optical fiber F2 can be coupled, and the laser light L2 can be coupled to the transmission optical fiber F3, so that the fiber laser oscillation device 1 can be configured more compactly.
In addition, since the excitation light source module 10 can be arranged in the vicinity of the center of the wound fiber laser optical fiber F2 so as to be vertically stacked, the volume ratio is high and the fiber laser oscillation device 1 is configured more compactly. can do.
Moreover, since the excitation light source module 10 and the fiber laser NA conversion optical system 30 can be replaced for each module, the maintainability is excellent.
The fiber laser oscillation device 1 is composed of two upper and lower layers, the excitation light source module 10 and the fiber laser NA conversion optical system 30 are arranged on one layer, and the optical fiber F2 for fiber laser is arranged on the other layer. As a result, the replacement of the optical fiber F2 for fiber laser becomes easy, and the maintainability is excellent.

  The fiber laser oscillator 1 and the fiber laser NA conversion optical system 30 of the present invention are not limited to the appearance and configuration described in the present embodiment, and various modifications and additions are possible without departing from the scope of the present invention. Can be deleted.

It is a figure explaining the external appearance and internal structure in one Embodiment of the fiber laser oscillation apparatus 1 of this invention. It is a figure explaining 1st Embodiment in the structure of NA conversion optical system 30 for fiber lasers. It is a figure explaining 2nd Embodiment in the structure of NA conversion optical system 30 for fiber lasers. It is a figure explaining the example of the structure of the conventional fiber laser oscillation apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fiber laser oscillator 10 Excitation light source module 30 NA conversion optical system for fiber lasers 31 1st lens 32 2nd lens 33 3rd lens 35 Selective reflection mirror 36 Laser reflection mirror LD Semiconductor laser array F1 Optical fiber for excitation light F2 Fiber laser Optical fiber F3 Transmission optical fiber F1A Bundling part F2A, F3A Connector P Laser focusing position

Claims (6)

An optical fiber for a fiber laser that emits the excited laser light from the end face when the excitation light is incident;
An excitation light source module that emits excitation light incident on the optical fiber for the fiber laser;
A fiber laser NA that condenses the excitation light and enters the end face of the fiber laser optical fiber, and condenses the laser light emitted from the end face of the fiber laser optical fiber at a preset laser condensing position. In a fiber laser oscillation device comprising a conversion optical system,
The optical fiber for the fiber laser is wound in a circular shape with a diameter capable of confining incident excitation light inside, and an end surface is directed in a direction of a tangent that is in contact with the circle,
The excitation light source module is disposed near the center of the wound fiber laser optical fiber, and emits the excitation light so as to cross the circle of the fiber laser optical fiber.
The NA conversion optical system for a fiber laser includes a selective reflection mirror that reflects the excitation light and transmits the laser light, a first lens, and a second lens,
The selective reflection mirror is disposed on an extension of the emission direction of the excitation light emitted from the excitation light source module, and the traveling direction of the excitation light reflected by the selective reflection mirror is wound in a circular shape. It is arranged at a predetermined angle so as to be in contact with the circle in the fiber laser optical fiber,
The end face of the optical fiber for the fiber laser is arranged so as to face the traveling direction of the excitation light reflected by the selective reflection mirror,
Between the selective reflection mirror and the end face of the optical fiber for the fiber laser, the first lens and the second lens transmit the parallel reflected excitation light reflected by the selective reflection mirror through the first lens. After being converted into light, the second lens is disposed so as to be condensed on the end face of the fiber laser optical fiber,
Laser light emitted from the end face of the fiber laser optical fiber passes through the second lens and is converted into parallel light, and then passes through the first lens and the selective reflection mirror. Focused on the laser focusing position set at the position to be the focal length,
Fiber laser oscillator. An optical fiber for a fiber laser that emits the excited laser light from the end face when the excitation light is incident;
An excitation light source module that emits excitation light incident on the optical fiber for the fiber laser;
A fiber laser NA that condenses the excitation light and enters the end face of the fiber laser optical fiber, and condenses the laser light emitted from the end face of the fiber laser optical fiber at a preset laser condensing position. In a fiber laser oscillation device comprising a conversion optical system,
The optical fiber for the fiber laser is wound in a circular shape with a diameter capable of confining incident excitation light inside, and an end surface is directed in a direction of a tangent that is in contact with the circle,
The excitation light source module is disposed near the center of the wound fiber laser optical fiber, and emits the excitation light so as to cross the circle of the fiber laser optical fiber.
The NA conversion optical system for a fiber laser includes a selective reflection mirror that reflects the excitation light and transmits the laser light, a first lens, a second lens, and a third lens,
The selective reflection mirror is disposed on an extension of the emission direction of the excitation light emitted from the excitation light source module, and the traveling direction of the excitation light reflected by the selective reflection mirror is wound in a circular shape. It is arranged at a predetermined angle so as to be in contact with the circle in the fiber laser optical fiber,
The end face of the optical fiber for the fiber laser is arranged so as to face the traveling direction of the excitation light reflected by the selective reflection mirror,
Between the excitation light source module and the selective reflection mirror, the first lens is arranged to convert the excitation light emitted from the excitation light source into parallel light,
Between the selective reflection mirror and the end face of the fiber laser optical fiber, the second lens transmits parallel light excitation light reflected by the selective reflection mirror through the second lens. It is arranged to be focused on the end face of the optical fiber,
The third lens is disposed on the extension of the emission direction of the laser light emitted from the fiber laser optical fiber and at a position after the laser light has passed through the second lens and the selective reflection mirror,
Laser light emitted from the end face of the fiber laser optical fiber passes through the second lens and is converted into parallel light, and then passes through the selective reflection mirror and the third lens. Focused on the laser focusing position set at the position to be the focal length,
Fiber laser oscillator. The fiber laser oscillation device according to claim 1,
A third lens is provided in the path between the selective reflection mirror and the laser condensing position to bring the laser condensing position closer to the selective reflection mirror.
Fiber laser oscillator. The fiber laser oscillation device according to any one of claims 1 to 3,
Furthermore, a laser reflecting mirror that reflects the laser beam and converts the laser focusing position into an arbitrary direction is provided,
The laser reflection mirror is disposed on an extension of the emission direction of the laser light emitted from the fiber laser optical fiber and at a position after passing through the selective reflection mirror,
Fiber laser oscillator. The pumping light emitted from the pumping light source module is incident on the end face of the fiber laser optical fiber, and the laser beam emitted from the fiber laser optical fiber pumped by the pumping light is set in a pre-set laser beam. A fiber laser NA conversion optical system that focuses light at a position,
The excitation light emitted from the excitation light source module and traveling in the first direction is reflected to change the traveling direction of the excitation light in a second direction different from the first direction, and on the extension of the second direction. A selective reflection mirror that transmits laser light emitted in the third direction opposite to the second direction from the end face of the optical fiber for the fiber laser disposed;
A first lens that is disposed between the selective reflection mirror and an end face of the fiber laser optical fiber and converts the excitation light reflected by the selective reflection mirror into parallel light;
A second lens disposed between the first lens and the end face of the fiber laser optical fiber, condensing the excitation light converted into the parallel light and entering the end face of the fiber laser optical fiber; With
The second lens converts the laser light emitted from the end face of the fiber laser optical fiber into parallel light,
The first lens condenses the laser light converted into the parallel light at a laser condensing position set on the extension in the third direction;
NA conversion optical system for fiber laser. The pumping light emitted from the pumping light source module is incident on the end face of the fiber laser optical fiber, and the laser beam emitted from the fiber laser optical fiber pumped by the pumping light is set in a pre-set laser beam. A fiber laser NA conversion optical system that focuses light at a position,
The excitation light emitted from the excitation light source module and traveling in the first direction is reflected to change the traveling direction of the excitation light in a second direction different from the first direction, and on the extension of the second direction. A selective reflection mirror that transmits laser light emitted in the third direction opposite to the second direction from the end face of the optical fiber for the fiber laser disposed;
A first lens that is disposed between the excitation light source module and the selective reflection mirror and converts the excitation light emitted from the excitation light source module into parallel light;
The fiber laser is disposed between the selective reflection mirror and the end face of the fiber laser optical fiber, condenses the excitation light converted into the parallel light, and enters the end face of the fiber laser optical fiber. A second lens for converting laser light emitted from the end face of the optical fiber into parallel light;
On the extension in the third direction, the laser beam emitted from the fiber laser optical fiber is disposed at a position after passing through the second lens and the selective reflection mirror, and on the extension in the third direction. A third lens for condensing the laser light at a set laser condensing position,
NA conversion optical system for fiber laser.

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