EP3014714A1

EP3014714A1 - Fiber laser apparatus

Info

Publication number: EP3014714A1
Application number: EP15702262.5A
Authority: EP
Inventors: Vitalij Lissotschenko; Aleksei Mikhailov
Original assignee: Lilas GmbH
Current assignee: LILAS GMBH
Priority date: 2014-02-06
Filing date: 2015-02-02
Publication date: 2016-05-04
Also published as: CN105191024A; CA2937044A1; US20160344154A1; JP2017508308A; EA201691577A1; SG11201606286XA; AU2015215066A1; WO2015117920A1; PH12016501543A1; KR20160117153A

Abstract

Disclosed is a fiber laser apparatus comprising at least one optical fiber (1) which has a fiber core made of or comprising a laser-active material and which is wound in loops, and pumping means (15) for optically pumping the fiber core of the at least one optical fiber (1) with pumping light (9), said pumping means (15) being designed in such a way that the pumping light (9) enters the at least one optical fiber (1) laterally from the outside during operation of the fiber laser apparatus.

Description

"Fiber laser device"

The present invention relates to a fiber laser device according to the preamble of claim 1.

Definitions: In the propagation direction of the laser radiation means mean propagation direction of the laser radiation, especially if this is not a plane wave or at least partially divergent. By laser beam, light beam, sub-beam or beam is, unless expressly stated otherwise, not an idealized beam of geometric optics meant, but a real light beam, such as a laser beam, which has no infinitesimal small, but an extended beam cross-section. Light should not just be the electromagnetic radiation of the visible

But the entire spectral range of electromagnetic radiation from the VUV to the FIR encompassed by the optics.

A fiber laser device of the aforementioned type is known from the US

6,178,187 B1 known. In the fiber laser described therein, a fiber core is provided which is doped with laser-active rare earth ions. Furthermore, a cladding of the optical fiber having a rectangular cross section is used. Pump light is introduced into this shell into the end, which during its movement couples through the wound loops of the optical fiber into the fiber core and generates laser radiation in it. The jacket with the rectangular cross section ensures the different

Laser modes are generated in the fiber core, so that a

More effective yield of the pump light can be achieved.

As with correspondingly long optical fibers, the intensity of the

Pump light in areas that are affected by the pumped light End of the optical fiber are removed, is relatively small, results in no uniform pumping over the length of the optical fiber. Furthermore, the cross-sectional area of the shell is comparatively small, so that only comparatively small pump powers can be achieved.

The problem underlying the present invention is to provide a fiber laser device of the type mentioned, with the high output power can be achieved.

This is inventively achieved by a fiber laser device of the type mentioned above with the characterizing features of claim 1. The subclaims relate to preferred

Embodiments of the invention.

According to claim 1 it is provided that the pumping means are designed such that the pumping light during operation of the

Fiber laser device laterally from the outside enters the optical fiber. Due to the lateral application of pumping light, pumping light of high intensity can be introduced into the fiber core over the entire length of the optical fiber. On the other hand, with a suitable design of the pumping means, large pumping powers can also be coupled into the fiber core, so that a high-power fiber laser can be created.

The pumping means may in particular be designed such that several windings or loops of the looped wound optical fiber are pumped simultaneously during operation of the fiber laser device. As a result, the pumping means can very effectively distribute the pumping light over long sections, in particular the entire length, of the optical fiber. It may be provided that the pumping means comprise at least one, in particular a plurality of transmission means into which pumping light is introduced during operation of the fiber laser device and from which or in which the pumping light into the optical fiber

is coupled. It can, for example, by increasing the transmission means or by increasing the number of

Transmission means are increased coupled into the fiber core pump power.

It is possible that the plurality of transmission means are spaced apart, in particular over the circumference of the windings or loops of the loops wound up

Optical fiber are spaced apart. In this way, space can remain between the transmission means, the

can be used for example for an optimized winding of the optical fiber.

It can be provided that the at least one

Transfer means a recess for the passage of the

Optical fiber has. This can be at least one

Transmission means surrounding the optical fiber at part lengths. If the spaces between the material of the transmission means in the region of the recesses and the optical fiber are as small as possible, the pump light can be comparatively undisturbed by the

Coupling transmission medium in the optical fiber. This coupling is improved in that in a preferred embodiment of the fiber laser device, the refractive index of the at least one transmission means substantially equal to the refractive index of the optical fiber, in particular substantially equal to

Refractive index of the fiber core, is. There is the possibility that several recesses are provided. It can be provided that the at least one

Transfer means, in particular that each of the transfer means consists of two parts, preferably of two halves, or comprises two parts, preferably two halves. The two parts can be corresponding recesses for the

Passage of the optical fiber have. Such a design makes it possible to construct a fiber laser device according to the invention relatively simply because only the two parts around the

Optical fiber laid around and connected to each other,

For example, glued together, must be.

There is a possibility that the at least one

Transmission means is designed such that during the

Operation of the fiber laser device coupled pump light

at least one reflection, preferably a plurality of reflections, in which at least one transmission means experiences, whereby the

Pumping efficiency is increased. This will do that in the

Transmission means coupled pump light used more effectively.

As a pump light source, a semiconductor laser or a plurality of semiconductor lasers, such as a laser diode bar or a stack of laser diode bars may be used. The laser light of this semiconductor laser or semiconductor laser can with

collimated suitable optics and in the at least one

Transfer means are introduced.

The fiber core may for example consist of glass, preferably of quartz glass. The fiber core may be doped with rare earth lasing ions such as ytterbium, neodymium or erbium ions. For example, in doping with ytterbium ions of

Fiber laser with a pump wavelength of 975 nm and a

Output wavelength of 1060 nm are operated.

It can be provided that one end of the fiber core

highly reflective, such as approximately 100% reflective, is formed and that the other end of the fiber core to

Coupling of the laser beam is used. This other end can then have a lower reflectivity for the outcoupled

Have laser light.

It is possible that the fiber laser device is designed such that during operation of the fiber laser device, the pump light at an angle in the at least one

Transmission medium is coupled. This angle ensures multiple reflections of the pump light in the at least one transmission means, which increases the pumping efficiency. As a result, the pumping light coupled into the transmission means is utilized more effectively. This angle and the divergence of the pump beam together should ensure that the beam is the zone of the at least one optical fiber or the beam of

Optical fibers or the loops of the at least one optical fiber in the at least one transmission means meets.

It can be provided that the inner diameter of the at least one recess in the at least one transmission means substantially corresponds to the outer diameter of the Lichtleitleitfaser, preferably that the inner diameter of the at least one recess less than 50 μιτι, in particular less than 30 μιτι, for example between 10 μιτι and 20 μιτι larger than the

Outer diameter of the optical fiber is. By the way in this way very small space between the optical fiber and the Transmission means, the pumping light comparatively unhindered or without additional reflections or refractions of the transmission medium into the optical fiber enter.

It may alternatively or additionally be provided that the

Inner diameter of the at least one recess in the

at least one transmission means substantially the

Outer diameter of the optical fiber or bundle of

Optical fibers or the plurality of loops of the optical fiber corresponds. Due to the very small gap between the optical fiber and the transmission means in this way, the pump light can enter the optical fiber comparatively unhindered or without additional reflections or refractions from the transmission medium.

It can be provided that the at least one

Transmission means has an area, in particular a window or an entrance surface, for the entry of the pumping light, this area being significantly smaller than the at least one highly reflecting area.

It can be provided that for the ratio q = di_ / dü between the diameter di_ of the at least one optical fiber or the bundle of optical fibers or the loops of the at least one optical fiber in the at least one transmission means and the diameter do of the at least one transmission means:

0.01 <q <1.0, in particular 0.05 <q <0.5, for example q = 0.1. There is the possibility that q is also less than 0.01.

By such a measure can be achieved that in

Inside the transmission means the pumping light impinges as often as possible on the optical fiber. This increases the pumping efficiency. There is the possibility that the fiber laser device comprises one or more optical fibers.

Other features and advantages of the present invention will become more apparent from the following description

Embodiments with reference to the accompanying

Illustrations. Show:

Fig. 1 is a plan view of a first embodiment of a

fiber laser device according to the invention;

Fig. 2 is an enlarged, schematic section according to the

Arrows A, B in Fig. 1;

Fig. 3 is a plan view of a second embodiment of a

fiber laser device according to the invention;

4 shows an enlarged, schematic section according to the

Arrows A, B in Fig.3;

5 shows a detailed view of the second embodiment according to FIG.

3;

Fig. 6 is a plan view of a third embodiment of a

fiber laser device according to the invention;

Fig. 7 is a detail view of a fourth embodiment of a

fiber laser device according to the invention;

Fig. 8 is a plan view of a fifth embodiment of a

fiber laser device according to the invention;

9 is an enlarged, schematic section according to the

Arrows A, B in Fig.8; 10 is a detailed view of a sixth embodiment of a fiber laser device according to the invention;

Fig. 11 is a schematic, perspective view of a seventh

Embodiment of an inventive

Fiber laser device;

FIG. 12 is a plan view of the embodiment of FIG. 11; FIG.

Fig. 13 is a schematic detail view of the embodiment

as shown in FIG. 11;

14 is a detail according to the arrow XIV in Fig. 13, the structure of an optical fiber of an inventive

Fiber laser device illustrates;

15 is a perspective view of a transmission means of the seventh embodiment of a fiber laser device according to the invention with running through the transmission means loops of the optical fiber.

16 shows a schematic side view of a transmission means of the seventh embodiment of a fiber laser device according to the invention with loops of the optical fiber running through the transmission means and with schematically indicated pumping means.

In the figures, identical or functionally identical parts are provided with the same reference numerals.

The illustrated in Fig. 1 and Fig. 2 embodiment of a fiber laser device according to the invention comprises an optical fiber 1, in a plurality of loops 2 or windings is wound up. The loops 2 run in such a way that they are arranged densely packed as shown in Figure 2, wherein the dense packing of the individual loops 2 of the optical fiber 1 a in the

Has substantially circular outline with a diameter di_.

In Fig.2 19 loops 2 are indicated. It is quite possible to provide fewer loops or more loops.

The optical fiber has a fiber core 4 and a fiber core

surrounding sheath 5 (see Fig. 14). In the usual way, the jacket 5 has a slightly lower refractive index than that

Fiber core 4, so that light can be guided in the fiber core 4 by total reflection. For example, the refractive index difference of cladding 5 and fiber core 4 may be 0.003 for NA = 0.1.

The fiber core 4 consists of a laser-active material or comprises a laser-active material. For example, the fiber core 4 is made of glass doped with rare earth ions such as ytterbium, neodymium or erbium ions. The glass may be quartz glass. In this case, the jacket 5 made of glass, in particular also consist of quartz glass.

The fiber core 4 may have a diameter of a few μιτι (single mode) up to 1000 μιτι and more (for example, 100 μιτι). The jacket 5 usually has a smaller thickness than that

Fiber core on (for example, 10 μιτι the coat and 100 μιτι the fiber core). The thickness of the shell should be as small as possible for technological reasons.

The two ends 6, 7 of the optical fiber are in the range of

Fiber core 4 provided with a coating so that For example, the left in Fig. 1 end 6 is highly reflective, for example, 99.8%. Furthermore, the right in Fig. 1 end 7 of the optical fiber 1 can serve as a decoupler and a smaller

Have reflectance. However, it may well also be provided that both ends 6, 7 of the optical fiber 1 are designed such that laser radiation can be coupled out of them.

The depicted embodiments of the invention

Fiber laser apparatus further comprise two transmission means 8, can be coupled through the in Fig. 1 schematically indicated pumping light 9 in the optical fiber 1. It exists, however

certainly also the possibility of more or less means of transmission

8 provide.

In the illustrated embodiment, each of the

Transmission means 8 from one side with pumping light 9 acted upon. For this purpose, each of the transmission means 8 a window 22 or an entrance surface through which the pumping light 9 in the

Transmission means 8 can occur.

There is quite a possibility of pumping from two directions

9 to enter the transmission means 8, as indicated in Figure 7. In this case, two windows are 22 or

Entry surfaces on opposite sides of the

Transmission means 8 arranged.

The transmission means 8 are spaced apart in the circumferential direction of the loops 2. The loops run 2 of the

Light guide 1 in the embodiments according to FIGS. 1 to 7 in the area of the transmission means 8 each linear, whereas they have a curvature 25 in the circumferential direction between the transmission means 8 (see Fig. 1). The transmission means 8 may each consist of two parts, which correspond in particular to each other and are designed as identical or mirror-inverted halves of the respective transmission means 8. However, there is a possibility that the parts are different from each other, for example, one of the parts being thicker, higher or wider than the other of the parts.

Furthermore, it is also possible to form the transmission means 8 in one piece.

Each of the transmission means is cylindrically shaped, wherein the lateral surface except for the window 22 and the

Entry surface is designed to be highly reflective, for example, by a highly reflective coating 23. The window 22nd

or the entry surface can be in particular in the axial direction over the entire length of the transmission means. 8

extend. The task of the transmission means 8 is the

Ensuring high pumping power in the zone where the optical fiber is located. The dimension of the transmission means 8 in the circumferential direction must be several times (1 to 10 times or even larger) greater than the diameter di_ of the at least one optical fiber 1 or the bundle of optical fibers 1 or more loops 2 of the at least one optical fiber 1. The length of the

Transmission means 8 in the axial direction corresponds to the entire length of the pumping beam and can vary in a wide range of a few mm and more. For example, the length of the

Transmission means 8 in the axial direction 100 mm in the case of pumping with several rows arranged

Laser diode bars.

Each of the transfer means 8 may be formed as a substrate of a transparent material such as quartz, and have the same refractive index as the optical fiber 1, in particular as the fiber core 4 or the cladding 5 of the optical fiber 1.

The transmission means 8 may comprise a closed hollow cylindrical receptacle 14 in which the loops 2 of the optical fiber 1 are arranged (see FIG. 10). In this case, the inner diameter of the receptacle 14 to the diameter di_ the dense packing of the individual loops 2 of the optical fiber 1 substantially

correspond. The sealed package is not necessarily located in the center of the receptacle 14. The transmission means 8 need not necessarily have a circular cross-section. To the

For example, the transmission means 8 can be elliptical

Have cross-section, in which the bundle of optical fibers is in a focal point of the ellipse, while the pumping light is focused on this or the second focal point. Even if the cross section of the transfer means 8 is circular, the bundle need not necessarily be centered, but may be spaced apart from the center, with the pumping light being focused on the bundle or on the center of the circle.

Alternatively, it is possible to use as a transmission means a hollow cylinder in the middle of the dense packing of the individual loops 2 of the optical fiber 1 extends. The inner surface is highly reflective except for a window 22nd

In the two-part design of the transmission means 8, the two parts may each have on the side facing the other part a recess which extends in the circumferential direction of the light guide 1 and in particular a semi-hollow cylindrical shape

having. The recesses of the parts complement each other to the closed hollow cylindrical recess 14 which surrounds the loops 2 of the optical fiber 1. In Fig. 1 Punnpnnittel 15 are indicated schematically. These can be one semiconductor laser or several as the pump light source

Semiconductor lasers, such as a laser diode bar or a stack of laser diode bars include. The pump light 9 serving as laser light of this semiconductor laser or this

Semiconductor laser can be collimated with suitable optics and coupled into the at least one transmission means 8. Because of the elongated window 22, the pumping light 9 should be a

have line-shaped intensity distribution, which extends in the axial direction of the transmission means 8. Ideally, the intensity distribution at the entrance to the transmission means 8 in the transverse direction of a line to a width corresponding to the width of the window 22, in particular, for example, about 100 μιτι. Furthermore, the intensity distribution ideally when entering the transmission means 8 in the line longitudinal direction has a length which corresponds to the length of the transmission means 8, in particular therefore for example about 100 mm.

The fiber laser device is designed such that during operation of the fiber laser device, the pumping light 9 in radial

Direction of the transmission means 8 enters this (see Figure 2). The deviation from the entrance slot is thus ideally a = 0 °. The reflective coatings 23 and the aforementioned angle α cause, through the window 22 and the

Entry surface entered pumping light 9 is repeatedly reflected in the interior of the transmission means 8 back and forth. In this way, the pumping light 9 penetrates the loops 2 of the optical waveguide 1 very frequently, so that the individual loops 2 of the optical waveguide 1 and in particular the fiber core 4 are very effectively acted upon by the pumping light 9. It can be seen that in particular the ratio q = di_ / dü between the diameter di_ of the at least one optical fiber 1 or the bundle of optical fibers 1 or the loops 2 of the

at least one optical fiber 1 in the at least one

Transmission means 8 and the diameter do of the at least one transmission means 8 is essential for the effectiveness of the fiber laser (see Fig.2). It may be appropriate that the ratio is greater than 0.01 and less than 1.0, preferably less than 0.5, for example equal to 0.1.

For example, the diameter di_ of the at least one

Lichtleitleitfaser 1 or the bundle of optical fibers 1 or the loops 2 of the at least one optical fiber 1 is about 1 mm to 2 mm. Furthermore, the diameter do of the at least one transmission means 8 may be about 8 mm.

In the embodiment of Figure 3 to Figure 5 are three

different optical fibers 1, 1 ', 1 "into a bundle of

Optical fibers or loops 2, 2 ', 2 "of optical fibers combined, resulting in three serving as an output ends 7, 7', 7" of the optical fibers.

More or less than three optical fibers 1, 1 ', 1 "can be combined into a bundle.

In the embodiment according to FIG. 6, four transmission means 8 are provided.

In the embodiment according to FIGS. 8 and 9, the

Loops 2 of the optical fiber 1 formed circular, so that there are no linear sections. Therefore, a single one

circulating torusformiges transmission means 8 is provided. Also in Figure 8 schematically individual pumping means 15 are indicated. It In this case, more pumping means 15 can be provided than are shown.

The seventh embodiment of a fiber laser device according to the invention shown in FIGS. 11 to 16 comprises a

Optical fiber 1, in a plurality of loops 2 or

Windings is wound on a coil-like holder 3. The loops 2 in this case run on the holder 3 such that they each have a constant spacing in the axial direction of the holder 3

or in the vertical direction in Fig. 11 spaced from each other are arranged one above the other.

In FIG. 11 and FIG. 16, nine loops 2 are indicated, whereas in FIG. 13 and FIG. 15 seven loops 2 are indicated. It is quite possible to provide fewer loops, such as two or three or four loops or even more loops, such as 10 or 11 or 12 or more loops.

The optical fiber 1 has a fiber core 4 and a fiber core

Fiber core 4, so that light can be guided in the fiber core 4 by total reflection. For example, the refractive index difference of cladding 5 and fiber core 4 may be on the order of about 0.003.

The fiber core 4 consists of a laser-active material or comprises a laser-active material. For example, the fiber core 4 is made of glass doped with rare earth ions such as ytterbium, neodymium or erbium ions. The glass may be quartz glass. In this case, the jacket 5 made of glass, in particular also consist of quartz glass. The two ends 6, 7 of the optical fiber 1 are in the range of

Fiber core 4 provided with a coating so that

For example, the right in Fig. 11 end 6 is highly reflective, for example in the range between 99% and 100%. Furthermore, the left in Fig. 11 end 7 of the optical fiber 1 serve as an output coupler and have a lower reflectance. However, it may well also be provided that both ends 6, 7 of the

Optical fiber 1 are designed such that from you laser radiation can be decoupled.

The depicted embodiments of the invention

Fiber laser devices further comprise a plurality of

Transmission means 8, can be coupled by the pump light 9 schematically indicated in Fig. 11 in the optical fiber 1. In the illustrated embodiments, six transmission means 8 are provided. However, there is also the possibility of providing more or less transmission means 8.

The transmission means 8 are spaced from each other in the circumferential direction of the holder 3. The loops run 2 of the

Light guide 1 in the area of the transmission means 8 each linear, whereas in the area between the transmission means 8, they have a curvature 25 in the circumferential direction (see Fig. 12).

It can be seen from FIGS. 13 and 15 that the transmission means 8 each consist of two parts 10, 11, which in particular correspond to each other and are designed as identical or mirror-inverted halves of the respective transmission means 8. However, there is a possibility that the parts 10, 11 from each other

are different, for example, one of the parts 10, 11 is thicker, higher or wider than the other of the parts 10, 11. Furthermore, they can also be characterized by other properties such as the arrangement in the following even more described reflective

Differentiate coatings.

Each of the parts 10, 11 has on its side facing the other part 10, 11 a plurality of recesses 12, 13 which extend in the circumferential direction of the light guide 1 and

in particular, have a semi-hollow cylindrical shape. In each case at the same height of the parts 10, 11 of the transmission means. 8

arranged recesses 12, 13 of the parts 10, 11 are complementary to a closed hollow cylindrical recess 14 which surrounds one of the loops 2 of the optical fiber 1. The loops 2 of the optical fibers 1 thus extend in the area of the transmission means 8 in the interior of this transmission means 8 (see FIG. 15).

The recesses 12, 13 are in particular designed so that their inner diameter comparatively exactly corresponds to the outer diameter of the optical fiber 1. In particular, the deviation of the inner diameter of the recesses 12, 13 of the

Outer diameter of the optical fiber 1 less than 50 μιτι,

in particular less than 30 μιτι, for example, between 10 μιτι and 20 μιτι. The parts 10, 11 of the transmission means 8 may have the same refractive index as the optical fiber 1, in particular as the

Fiber core 4 or the jacket 5 of the optical fiber 1 have.

For example, the parts 10, 11 of the transmission means 8 made of glass, in particular made of quartz glass.

In the holder 3, in each case in the region of the transmission means 8, a recess 14 is provided inwards, in which a part 10 of the transmission means 8 is arranged (see FIGS. 11 and 12). In this way it is achieved that the optical fiber 1 extends without radial displacement of the area between the transmission means 8 in the respective transmission means 8 in (see Fig. 12). In Fig. 16 Punnpnnittel 15 are indicated schematically. These can be one semiconductor laser or several as the pump light source

Semiconductor laser can be collimated with suitable optics and coupled into the at least one transmission means 8.

The illustrated in Fig. 15 and Fig. 16 embodiment of a

Transmission means 8 has a flat, cuboid shape. The transmission means 8 has two lateral end faces 16, 17 for the entry and exit of the loops 2 of the optical fiber 1. Furthermore, the transmission means 8 has a top end 18, 19 which is upper in FIGS. 15 and 16 and a lower end 18, 19 in FIGS. 15 and 16. Furthermore, the transmission means 8 has a front side 20 in FIG. 15 and a flat side 21 in FIG. 15.

The upper end side 18 in FIGS. 15 and 16 is provided with a reflective coating 23, with the exception of a small section serving as the entrance surface 22 for the pumping light 9. The lower end face 19 in FIGS. 15 and 16 is completely provided with a reflective coating 24.

It is entirely possible, in addition to the upper and lower end faces 18, 19 in FIGS. 15 and 16, to have further sides, such as the right and left end faces 16, 17 in FIGS. 15 and 16, or those in FIG. 15 and Fig. 16 front and rear planar sides 20, 21 to be provided with reflective coatings.

The fiber laser device is designed such that during operation of the fiber laser device, the pumping light 9 under a

Angle a, for example, at an angle a between 5 ° and 10 ° is coupled to the solder on the entrance surface 22 into the at least one transmission means 8. The reflective ones

Coatings 23, 24 and the aforementioned angle .alpha. Cause the pumping light 9, which has entered through the entry surface 22, to be located several times in the interior of the transmission means 8 between the lower end 18 in FIGS. 15 and 16 and the upper end side 18 in FIGS. 15 and 16. 19 is reflected back and forth. In this way, the pumping light 9 penetrates the loops 2 of the light guide 1 several times.

15 shows that the light bundle of the pumping light 9 impinging on the entry surface 22 covers the entire depth of the entry surface 22 in the radial direction of the holder 3 or in the direction extending in the plane of the drawing of FIGS. 15 and 16. Due to the substantially same refractive index of the transmission means 8 and the optical fiber 1, the

Pumplicht 9 in the interior of the transmission means 8 spread relatively unhindered, so that the individual loops 2 of the optical fiber 1 and in particular the fiber core 4 are very effectively acted upon by the pumping light 9.

Claims

claims:

A fiber laser device comprising an optical fiber (1) with a fiber core (4) consisting of a laser-active material or comprising a laser-active material, wherein the optical fiber (1) is wound up like a loop,

Pump means (15) for the optical pumping of the fiber core (4) with pumping light (9), characterized in that the pumping means (15) are designed such that the pumping light (9) during the operation of the fiber laser device laterally from the outside into the optical fiber ( 1) occurs.

Fiber laser device according to claim 1, characterized

in that the pumping means (15) comprise at least one transmission means (8) into which pumping light (9) is introduced during operation of the fiber laser device and from which or in which the pumping light (9) is coupled into the at least one optical fiber (1) , and wherein the at least one transmission means (8) or each of the transmission means (8) has a recess (14) or a cavity for the

Passage of a bundle of optical fibers (1) or

a plurality of loops (2) of the at least one optical fiber (1) or have.

Fiber laser device according to one of claims 1 or 2, characterized in that the pumping means (15) are designed such that during operation of the

Fiber laser device several windings or loops (2) the loop-like wound optical fiber (1) are pumped simultaneously.

4. Fiber laser device according to one of claims 1 to 3,

characterized in that the pump means (15)

at least one, in particular a plurality of transmission means (8), in which during operation of the

Fiber laser device pump light (9) is coupled and from which the pumping light (9) is coupled into the optical fiber (1).

5. Fiber laser device according to one of claims 1 to 4,

characterized in that the plurality

Transmission means (8) are spaced apart, in particular over the circumference of the windings or loops (2) of the loop-like wound optical fiber (1) are spaced apart.

6. Fiber laser device according to one of claims 1 to 5,

characterized in that the at least one

Transfer means (8) at least one, preferably a plurality of recesses (12, 13) for the passage of the

Optical fiber (1).

7. Fiber laser device according to one of claims 1 to 6,

characterized in that the at least one

Transmission means (8) has a recess (14) or a cavity for the passage of the Lichtleitleitfaser (1) or a bundle of optical fibers (1) or more loops (2) of the optical fiber (1).

8. Fiber laser device according to one of claims 1 to 7,

characterized in that the at least one Transmission means (8) surrounding the optical fiber (1) at part lengths.

9. Fiber laser device according to one of claims 1 to 8,

characterized in that the at least one

Transmission means (8) surrounds the bundle of optical fibers (1) or a plurality of loops (2) of the optical fiber (1) at partial lengths.

10. Fiber laser device according to one of claims 1 to 9,

characterized in that the refractive index of the at least one transmission means (8) is substantially equal to the refractive index of the optical fiber (1), in particular substantially equal to the refractive index of the fiber core (4).

11. Fiber laser device according to one of claims 1 to 10,

characterized in that the at least one

Transfer means (8) comprises a substrate or consists of a substrate through which the pumping light (9) passes.

12. Fiber laser device according to one of claims 1 to 11,

characterized in that the refractive index of the substrate of the at least one transmission means (8) is substantially equal to the refractive index of the optical fiber (1), in particular substantially equal to the refractive index of the fiber core (4).

Fiber laser device according to one of claims 1 to 12, characterized in that the at least one

Transmission means (8) is at least partially hollow, in particular at least partially has a hollow cylindrical shape.

14. Fiber laser device according to one of claims 1 to 13, characterized in that the at least one

Transmission means (8) is integrally formed.

15. Fiber laser device according to one of claims 1 to 14,

characterized in that the at least one

Transmission means (8), in particular that each of the

Transmission means (8), consists of two parts, preferably of two halves, or two parts, preferably two halves comprises.

16. Fiber laser device according to one of claims 1 to 15,

characterized in that the two parts have mutually corresponding recesses (12, 13) for the passage of the Lichtleitleitfaser (1).

17. Fiber laser device according to one of claims 1 to 16,

characterized in that the two parts have mutually corresponding recesses for the passage of the bundle of optical fibers (1) or more loops (2) of the optical fiber (1).

18. Fiber laser device according to one of claims 1 to 17,

characterized in that the at least one

Transmission means (8) is designed such that the coupled during operation of the fiber laser device pumping light (9) at least one reflection, preferably a plurality

Reflections in which at least one transmission means (8) experiences, whereby the pumping efficiency is increased.

19. Fiber laser device according to one of claims 1 to 18,

characterized in that the at least one

Transmission means (8) at least one highly reflective Area, in particular at least one area with a highly reflective coating (23).

20. Fiber laser device according to one of claims 1 to 19,

characterized in that the fiber laser device is designed such that during operation of the

Fiber laser device, the pumping light (9) at an angle (a) into the at least one transmission means (8) is coupled.

21. Fiber laser device according to one of claims 1 to 20,

characterized in that the at least one

Transmission means (8) has a region, in particular a window (22) or an entrance surface, for the entry of the pumping light (9), this region being significantly smaller than the

is at least one highly reflective area.

22. Fiber laser device according to one of claims 1 to 21,

characterized in that the inner diameter of the at least one recess (12, 13) in the at least one transmission means (8) substantially the

Outer diameter of the optical fiber (1) corresponds,

preferably that the inner diameter of the at least one recess (12, 13) less than 50 μιτι, in particular less than 30 μιτι, for example, between 10 μιτι and 20 μιτι greater than the outer diameter of the optical fiber (1).

23. Fiber laser device according to one of claims 1 to 22,

characterized in that the inner diameter of the at least one recess (14) in the at least one transmission means (8) is substantially equal to the outer diameter (di_) of the optical fiber (1) or the beam of Optical fibers (1) or the plurality of loops (2) of the

Optical fiber (1) corresponds.

24. Fiber laser device according to one of claims 1 to 23,

characterized in that for the ratio q = di_ / dü between the diameter (di_) of the optical fiber (1) or the bundle of optical fibers (1) or the loops (2) of the at least one optical fiber (1) in the at least one transmission means ( 8) and the diameter (du) of the at least one

Transmission means (8) applies:

0.01 <q <1.0, in particular 0.05 <q <0.5, for example q = 0.1.

25. Fiber laser device according to one of claims 1 to 24,

characterized in that the fiber laser device comprises one or more optical fibers (1, 1 ', 1 ").

26. Fiber laser device according to one of claims 1 to 25,

characterized in that the pump means (15)

at least one transmission means (8), into which during the operation of the fiber laser device pumping light (9) is introduced and from which or in which the pumping light (9) is coupled into the at least one optical fiber (1), wherein the at least one transmission means (8 ) the at least one optical fiber (1) or the bundle of optical fibers (1) or more loops (2) of the at least one optical fiber (1) surrounds at least at partial lengths, wherein the at least one transmission means (8) is cylindrically shaped and wherein the Fiber laser device is designed such that during operation of the fiber laser device, the pumping light (9) in the radial direction of the at least one cylindrical

Transmission means (8) or at an angle (a) less than 90 °, in particular less than 45 °, preferably less than 30 ° to the radial direction in the at least one transmission means (8) is coupled.