WO2021260010A1

WO2021260010A1 - Fibre coupler

Info

Publication number: WO2021260010A1
Application number: PCT/EP2021/067155
Authority: WO
Inventors: Andreas Rudolf
Original assignee: Precitec Gmbh & Co. Kg
Priority date: 2020-06-26
Filing date: 2021-06-23
Publication date: 2021-12-30
Also published as: CN115720637A; DE102020116895B4; DE102020116895A1

Abstract

The invention relates to a fibre coupler for securing a laser-light-guiding fibre to a laser machining head, comprising: a housing having an outlet opening arranged on an end side of the housing for letting laser light out of the fibre coupler, and a flange at least partially surrounding the outlet opening and with a contact surface for securing the fibre coupler to a laser machining head; and a laser-light-guiding fibre having a fibre end, wherein the fibre end is secured in the housing, in a region of the housing opposite the outlet opening, such that laser light exiting the fibre end is directed though the outlet opening.

Description

Fiber coupler

Technical area

The present invention relates to a fiber coupler for attaching a laser light guide fiber to a laser processing head.

background

In a laser processing system for processing a workpiece by means of a laser beam, the laser beam emerging from one end of a laser guide fiber is focused or bundled onto a workpiece to be processed with the help of beam guidance and focusing optics in order to locally heat the workpiece to the melting temperature. The processing can in particular include laser welding or laser cutting. The laser processing system comprises a laser processing head, in particular a laser welding head or laser cutting head. In order to lead the laser light from the laser source into the laser processing head, an optical fiber is generally used, also called optical fiber, optical fiber or optical fiber for short, in which the optical fiber is guided by total reflection.

The interface between the optical fiber and the laser processing head is of utmost importance for the most loss-free, precisely defined and easily reproducible coupling into the laser processing head, especially with high laser powers from 1 kW. There are numerous industry standards in the field of fiber plugs / sockets. Two standards in particular have established themselves for high-power lasers: QBH and D. As a rule, the interface between the optical fiber and the laser processing head is two-part and consists of a fiber connector integrated with the optical fiber and a fiber socket mounted on the laser processing head. The optical fiber typically ends in what is known as the fiber connector, which is inserted and locked along the length of the fiber socket attached to the processing head. The position of the fiber connector in the laser processing head system is defined by the fiber socket. This definition of position is a prerequisite for the optical guidance of the laser beam. In addition, the connection between the fiber connector and the fiber socket and the connection between the fiber socket and the laser processing head must ensure a hermetically sealed demarcation from the environment, also in order to to avoid the penetration of dirt particles into the optical beam path of the laser processing head.

A schematic representation of such a conventional interface between the optical fiber and the laser processing head is shown in FIG. 1: In a first step, a fiber bushing 3 is attached to a laser processing head 100, for example by means of screws 33. To align the fiber bushing 3 with respect to the optical axis of the laser processing head 100, an annular projection can be provided on one of the two components laser processing head 100 and fiber bushing 3 (also called centering collar) and a corresponding recess on the other of the two components. The fiber connector 2, in which one end of the optical fiber 1 is attached or integrated, is then inserted into the fiber socket 3 and locked therein after the fiber connector 2 has been aligned or centered. Since the centering takes place via cones or cylinders pressed into one another of the fiber connector and the fiber socket, a high degree of manufacturing and fitting accuracy of the two components is required. However, plugs and sockets are usually manufactured by different manufacturers, so that this accuracy can often not be sufficiently guaranteed. In addition, there is the problem of contact corrosion during movement or vibration.

The cylindrical or conical fiber connector is inserted into the narrow fiber socket, usually over a length of at least 40 mm, manually by a specialist who has to insert the connector smoothly and with high precision into the fiber socket attached to the laser processing head. Due to the tight mechanical tolerances, frictional contacts between plug and socket are unavoidable. This can result in metallic abrasion, which then gets onto the optical fiber end and / or the optics of the processing head - be it immediately or later when the head is moved. If the connected high-power laser is then switched on, this can lead to irreparable damage to the fiber end face and / or the optics, as the metal particles heat up strongly and burn themselves into the glass material.

The termination of the fiber connector is typically formed by a protective glass 4, which protects the end of the optical fiber and in particular the end surface or exit surface of the optical fiber target. The protective glass is embedded in a metal sleeve with a thread and is screwed onto the fiber plug. As a result of the screwing on, metallic abrasion can in turn arise, which then reaches the optical fiber end and / or the optics of the processing head, with the same consequences as described above. Another disadvantage of the conventional connection between optical fiber and laser processing head is that, as soon as the plug has been inserted into the socket, the protective glass can no longer be inspected, since it is completely surrounded by the fiber socket and laser processing head. To inspect the protective glass, the fiber connector must first be removed from the fiber socket. This process - just like the subsequent plugging process - is again associated with the risk of abrasion.

In practice, some of the laser radiation is absorbed on surfaces. In order to ensure stable operation of the system, the fiber plug 2 and the fiber socket 3 are each provided with their own cooling circuit WK for cooling with external water. Another cooling circuit WK must also be provided for a diaphragm 5 in the laser processing head 100. This not only increases the installation space of the individual components, but also the risk of leakage in the area of the external water connections.

In Fig. 1, the functions of the various areas of the fiber socket 3 and the fiber connector 2 are marked with arrows. The arrows A here mark an area of the fiber socket 3, which is used for centering or alignment with respect to the laser processing head 100, and an area of the fiber connector 2, which is used for centering or alignment with respect to the fiber socket 3. The arrows B mark an area of the fiber bushing 3, which is used for sealing with respect to the laser processing head 100, and an area of the fiber plug 2, which is used for sealing with respect to the fiber bushing 3. The arrow C marks an area of the fiber connector 2 which provides electrical contacts for a safety circuit. The arrow D marks an area of the fiber connector 2, which is used to fasten conditions to the fiber socket 3.

From EP 1 562 058 A1 a plug connection for a laser light guide cable connector is known which comprises a plug, a socket and an actuating element for releasing or locking the connection. Summary of the invention

It is an object of the present invention to provide a fiber coupler for attaching a laser optical fiber to a laser processing head, which enables a play-free, firm and reproducible connection of the laser optical fiber with the laser processing head, through which a laser beam is coupled into the laser processing head with the lowest possible loss of power and quality can be. It is also an object of the present invention to provide a fiber coupler for attaching a laser optical fiber to a laser processing head, which enables a reliable and tight connection of the laser optical fiber with the laser processing head in a simple and compact manner.

The tasks are solved by the subject matter of the independent claim. Features of advantageous configurations are set out in the subclaims.

The present invention is based on the idea of providing a fiber coupler which can connect a laser optical fiber directly to the laser processing head. So there is no need for a further connection element. A plugging process or a connecting process with strong mechanical friction can thus be dispensed with and the risk of dirt particles entering the optical path of the laser processing head can be reduced.

According to one embodiment, a fiber coupler for attaching a laser light guide fiber to a laser processing head comprises: a laser light guide fiber with a fiber end as well as a housing with an exit opening for an exit of laser light from the fiber coupler and a flange at least partially surrounding the exit opening with a contact surface for attaching the Fiber coupler on a laser processing head. The fiber end is fastened or integrated in a region of the housing opposite the exit opening in such a way that laser light emerging from the fiber end falls through the exit opening. The outlet opening and / or the contact surface can be arranged on an end face of the housing or of the fiber coupler. The end face can also be referred to as the end face of the housing or the fiber coupler in the direction of laser beam propagation. According to the invention, a connection between an optical fiber and a laser processing head can be made with only one element, instead of two as before. Thus, only one assembly process, ie only one centering process and one fastening process, is not necessary and the number of potential leaks is reduced. Due to the better accessibility, a visual inspection of the head is simplified as long as the fiber coupler is not yet mounted. This enables simpler, faster and safer handling, in particular installation or assembly, by specialist personnel. In addition, there is no need to plug a fiber connector into a socket, so that the risk of contamination due to abrasion or contact corrosion is greatly reduced. This increases the long-term stability of the overall system and reduces the overall complexity, which also leads to cost savings.

The fiber end of the laser optical fiber is integrated in the housing, i.e. firmly connected to the housing. The laser optical fiber can have a so-called fiber end block at the fiber end. In other words, the fiber end can be designed as a fiber end block. An end face or end face of the fiber end block then serves as a light exit face for laser light from the laser optical fiber. The fiber end block can be a cylinder, for example made of quartz glass or of the same material as the laser optical fiber itself, which is fused onto the laser optical fiber or spliced to the fiber end. In this case the fiber end block can be fixed, e.g. glued, in the housing. An optical axis of the fiber end can lead through the center point of the light exit surface of the fiber end or the fiber end block and / or be perpendicular to the light exit surface.

A region of the housing in which the fiber end is fastened and the flange or the contact surface are preferably formed in one piece. As a result, stability can be increased and play or freedom of movement in the assembled state of the fiber coupler can be reduced.

The contact surface can extend perpendicular to a laser beam propagation direction and / or perpendicular to an optical axis of the fiber end and / or parallel to a light exit surface of the fiber end. The fiber coupler can be connected flush with the laser processing head via the contact surface. The contact surface preferably forms one End face of the fiber coupler in the direction of laser beam propagation and / or along an optical axis of the fiber end. The contact surface can lie on an end face of the fiber coupler or form an end face of the fiber coupler. The contact surface can be essentially flat or planar. The contact surface is preferably designed in such a way that the fiber coupler can be connected flush with the laser processing head. In other words, no other part of the fiber coupler extends further in the direction of laser beam propagation than the contact surface of the flange. The contact surface can be designed in accordance with a coupling surface of the laser processing head in order to close flush with it. This means that the fiber coupler is not plugged in or inserted. The contact surface can therefore be designed as an essentially flush end surface of the fiber coupler perpendicular to the optical axis of the fiber end or perpendicular to the direction of laser beam propagation.

The contact surface and the outlet opening are preferably in one plane. In other words, the contact surface and the outlet opening can be arranged at the same height along an optical axis of the fiber end and / or in the direction of laser beam propagation. This means that the outlet opening can be formed in the contact surface. The contact surface can surround the outlet opening. In particular, the contact surface can adjoin the outlet opening. The contact surface and the outlet opening can be arranged perpendicular to an optical axis of the fiber end and / or to the direction of laser beam propagation. The exit opening and the fiber end, in particular a light exit surface of the fiber end, are spaced apart from one another in the direction of laser beam propagation or along the optical axis of the fiber end. In other words, the fiber end, in particular a light exit surface of the fiber end, is arranged in the housing or in the interior of the housing.

The flange, in particular the contact surface, can be provided with fastening means in order to fasten the fiber coupler to the laser processing head. The fastening means can include, for example, a hole or a threaded hole for a screw, or also a threaded hole with a screw, a latch, a bolt and the like. The fastening means of the fiber coupler are preferably designed corresponding to fastening means of the Laserbear processing head. The fastening means are preferably on an outer edge of the flange arranged. The flange can extend outwardly from the housing, preferably radially. The outlet opening can be completely surrounded by the flange and / or by the contact surface. In other words, the flange and / or the contact surface can be designed in an annular manner or surround the outlet opening in an annular manner. Alternatively, the flange may comprise one or more projections extending radially outward from the housing. An outer circumference of the flange, or a cross section of the flange in a plane perpendicular to the direction of laser beam propagation, can be circular or rectangular. The flange can extend perpendicular to a laser beam propagation direction and / or perpendicular to an optical axis of the fiber end and / or parallel to a light exit surface of the fiber end. The outlet opening is preferably circular.

The housing can have an interior space adjoining the outlet opening. The interior space is therefore preferably open to the outside of the fiber coupler through the outlet opening. The fiber end can protrude into the interior or be arranged in the interior. The fiber end can be spaced from a side wall of the interior space. The side wall of the interior can denote a wall which delimits or surrounds the interior, in particular in the radial direction or in a direction perpendicular to the laser beam propagation direction. The side wall of the interior can in particular be a wall which extends in the direction of laser beam propagation. The interior space can be cylindrical in essence union.

Preferably, at least two of the following elements are arranged coaxially: the outlet opening, the interior space, the fiber end, the fiber end block, the flange, and the contact surface.

In the housing of the fiber coupler, ie in the interior of the housing, a protective glass cap can be fastened to surround the fiber end. The protective glass cap can comprise a protective glass and a holder, for example a sleeve, in particular a metal sleeve. The protective glass cap can be fastened in the housing in such a way that the protective glass is arranged parallel to a light exit surface of the laser optical fiber. Thus, the laser beam can pass through the protective glass cap unhindered, but is at the same time in front Dirt particles and damage protected. In another embodiment, an interchangeable cassette with a protective glass can be provided between the outlet opening and the fiber end. The interchangeable cassette can be accessed from an outside of the housing. For example, the interchangeable cassette can be provided perpendicular to the direction of laser beam propagation or to the optical axis of the fiber end so that it can be accessed, in particular pushed in and pulled out, in the housing. As a result, the protective glass can easily be replaced without having to remove the fiber coupler from the laser processing head. This means that the protective glass can also be checked and replaced after installation.

Between the outlet opening and the fiber end, a diaphragm is preferably provided to absorb unwanted edge radiation. The edge radiation does not even penetrate through the diaphragm into the processing head, but is absorbed at the earliest possible point in time. A corresponding aperture in the processing head can therefore be omitted. The diaphragm can be designed to limit a diameter of the laser beam emerging from the fiber coupler. The screen can be integrated in the fiber coupler or in the housing of the fiber coupler. In other words, the diaphragm can be arranged in the interior of the housing in front of the outlet opening. The panel can also be arranged in an interchangeable cassette that can be pushed into and pulled out of the housing.

Furthermore, at least one sensor can be provided in the housing or in the interior of the housing. The at least one sensor can be arranged adjacent to the fiber end or between the outlet opening and the fiber end. The at least one sensor, for example for temperature or scattered light detection, can be provided adjacent to the diaphragm or between the diaphragm and the outlet opening. The at least one sensor can also be arranged on the outlet opening or in the outlet opening. The sensor can be fastened in the housing or arranged to be exchangeable. The sensor can be arranged, for example, in an interchangeable cassette that can be pushed into and pulled out of the housing. The interchangeable cassette is preferably in the form of a frame with an opening for the laser beam to pass through. The sensor can be a thermal sensor or an optical sensor. The sensor can be set up to detect at least one parameter for the fiber end and / or a protective glass and / or a screen. The sensor can for example be a temperature sensor or a scattered light sensor. The signal transmission can take place to the laser processing head and / or to a higher-level control unit of the laser processing device. The signal transmission can be electrical or optical, or wired or wireless.

The housing can have a cooling circuit, e.g. a cooling circuit with a water connection for cooling with water. The cooling circuit can be set up to cool the housing, a protective glass arranged in the housing, and / or a screen arranged in the housing. Due to the reduced number of cooling circuits, costs and the risk of leakage can be reduced.

The flange or the contact surface can have at least one sealing element for sealing between the fiber coupler and the laser processing head and / or a receptacle for such a sealing element. The sealing element can comprise a sealing ring or an O-ring. The receptacle can be a groove for receiving a sealing element. The sealing element or the receptacle preferably surround the outlet opening. The you telement or the receptacle can be arranged directly adjacent or adjacent to the outlet opening on the contact surface of the flange.

The flange or the contact surface can have at least one alignment element for aligning the fiber coupler on the laser processing head. For example, the contact surface can comprise a centering groove or a centering recess. Alternatively, a centering collar or centering collar or a centering projection or a centering nose can be formed on the contact surface. Alternatively, the flange or the contact surface can have dowel pins or bores. A coupling surface of the laser processing head can have a corresponding alignment element that corresponds to the alignment element on the contact surface, for example corresponding holes for the dowel pins attached to the contact surface or dowel pins corresponding to the holes formed in the contact surface. This makes it easier to center the optical axis of the fiber coupler or the fiber end with respect to the laser processing head, that is to say with respect to an optical axis of the laser processing head. The fiber coupler can be designed for coupling or importing a high-power laser beam. In other words, the laser beam can have a power of 1 kW or more. A safety circuit is required in the field of high-power lasers. The laser beam is only generated by a laser source when the safety circuit is closed. The flange or the contact surface can therefore comprise at least one electrical contact or at least one interface for a safety circuit. This makes it possible to quickly determine whether the fiber coupler is correctly mounted on the laser processing head.

The flange or the contact surface can have at least one interface for a sensor provided in the fiber coupler to the laser processing head and / or to a higher-level control unit of the laser processing device.

According to a further aspect, a laser processing device is specified, comprising a laser processing head with a coupling surface to which a fiber coupler according to one of the embodiments described herein is attached, and a coupling opening for coupling the laser beam into the laser processing head, wherein the contact surface of the fiber coupler is in contact with the coupling surface and the exit opening of the fiber coupler is opposite the coupling opening. The coupling surface is preferably a part of an outer surface of the laser processing head. The laser processing head can furthermore comprise an optical beam path. The optical beam path can run in a so-called optical space in a housing of the laser processing head. The laser processing device can comprise a laser source, in particular a high-power laser source. The laser source can be set up to generate a laser beam of at least 1 kW.

Brief description of the drawings

The invention is described in detail below with reference to figures.

Fig. 1 shows a connection between optical fiber and laser processing head with fiber plug and fiber socket according to the prior art; 2 shows a fiber coupler in accordance with embodiments of the present invention;

3 shows a laser processing device with a fiber coupler according to embodiments of the present invention; and

4 shows a laser processing device with a fiber coupler according to further embodiments of the present invention.

Detailed description of the embodiments

Unless otherwise noted, the same reference numerals are used below for identical and identically acting elements.

Fig. 2 shows a fiber coupler for attaching a laser optical fiber (hereinafter optical fiber) to a laser processing head according to an embodiment of the present invention. The fiber coupler comprises a housing 20 in which an optical fiber 10 is integrated. A fiber end 11 of the optical fiber 10 opens into an interior 24 of the housing 20. The interior 24 is open to an outside of the housing 20 through an exit opening 21 so that laser light emerging from the fiber end 11 can exit the fiber coupler through the exit opening 21. The fiber end 11 can, as shown in the figures, be designed as a fiber end block. For example, a quartz block can be spliced to one end of the laser optical fiber 10. However, the present invention is not limited to this. The fiber end 11 can thus also comprise an end of a laser optical fiber 10 which does not have a fiber end block.

The housing 20 has a flange 25 for attachment to a laser processing head which adjoins the outlet opening 21. The flange 25 is preferably designed to protrude radially outward. In the embodiment shown in FIG. 2, the flange 25 is designed to be annular or to completely surround the outlet opening 21. An outer circumference of the flange, ie in the radial direction or in a plane perpendicular to the optical axis of the fiber end 11 or perpendicular to the laser beam propagation direction, can be circular or rectangular, in particular square. As an alternative to an annular design, the flange 25 can also comprise several projections that extend from the housing se 20, preferably radially, protrude outward. A surface of the flange 25 adjoining the outlet opening 21 serves as a contact surface 26 which is in contact with the laser processing head in the assembled state of the fiber coupler. The flange 25 also has fastening means 22 for fastening the fiber coupler to the laser processing head, which are designed as through holes in FIG. 2 in order to carry out a screw or a bolt. The housing 20 can also have a cooling circuit WK for water cooling.

A cap 40 with a protective glass 44, which surrounds the fiber end 11, is optionally provided in the housing 20. The cap 40 is removably fastened in the interior 24 of the housing 20, for example by means of a thread or a plug-in or bayonet connection. In this way, the protective glass 40 can be replaced in the event of contamination or damage.

The fiber coupler according to the present invention thus has, with the contact surface 26, a substantially flush end surface perpendicular to the optical axis of the fibers of FIG. 11, which is provided with fastening means. In this way, the fiber coupler can be attached to a laser processing head in a stable and simple manner without a plugging process or any other mechanical fastening process associated with abrasion.

3 shows a laser processing device with a laser processing head 100, to which the fiber coupler according to an embodiment of the present invention is attached by means of attachment means 23, such as screws or bolts. In the assembled state of the fiber coupler, the contact surface 26 of the flange 25 and a coupling surface of the laser processing head lie against one another. The exit opening 21 of the fiber coupler is aligned with a coupling opening of the laser processing head in such a way that the laser beam emerging through the exit opening 21 is coupled or introduced through the coupling opening into the beam path of the laser processing head. In the optical space or in the optical beam path of the laser processing head 100, an interchangeable cassette 110 with a protective glass 111 is arranged at the beginning, ie adjacent to the coupling opening, in order to seal the optical space or the optical beam path and protect it from incoming dirt. Furthermore, a screen 5 can be provided in order to To absorb edge rays of an incident laser beam in a targeted manner. In order to prevent the screen from heating up due to the absorption of radiation, a cooling circuit can be provided (arrow next to screen 5).

In order to simplify the alignment of the fiber coupler on the laser processing head 100 or the centering of an optical axis of the fiber end 11 of the optical fiber 10 with respect to the optical beam path of the laser processing head 100, the flange 25, in particular the contact surface 26, can be provided with an alignment element 27. As shown in FIG. 3, the fiber coupler and laser processing head are almost flush with one another, with the exception of the alignment element which is designed as a centering collar and is typically a few millimeters in height. The centering collar can be located either on the fiber coupler or on the laser processing head. In the embodiment of FIG. 3, the alignment element 27 is a groove or recess formed in the contact surface 25. A corre sponding alignment element is formed on a coupling surface of the laser processing head 100, in Fig. 3 as a projection or collar.

4 shows a fiber coupler according to a further embodiment of the present invention, which is attached to a laser processing head 100. As shown in FIG. 4, a fiber coupler according to embodiments of the present invention can have an exchangeable cassette 400 with a protective glass 44 which is provided in the housing 20 in an exchangeable manner. The protective glass 44 is arranged between the fiber end 11 and the outlet opening 21 of the housing 20 in order to protect the fiber end 11 from contamination and damage. The interchangeable cassette 400 can be moved into and out of the housing 20 in a direction perpendicular to the direction of laser beam propagation or perpendicular to the optical axis of the fibers of FIG. In this way, an exchange or an inspection of the protective glass 44 is possible without dismantling the fiber coupler from the laser processing head.

Furthermore, a screen 50 for absorbing edge radiation of the laser beam can be arranged in the housing between the fiber end 11 and the outlet opening 21, for example between the protective glass 44 and the fiber end 11 or between the protective glass 44 and the outlet opening. Since the screen 50 heats up strongly due to the absorption of radiation, For example, the housing 20 of the fiber coupler can be provided with a cooling circuit WK which is set up to cool the screen 50 and / or the exchangeable cassette 400.

The fiber coupler can also comprise at least one sensor 60, for example a sensor for detecting a temperature or scattered light in the interior 25 of the housing or from a side wall of the interior 25. The sensor 60 can in particular be set up to parameters such as scattered light intensity or temperature of a protective glass 44 or from the fiber end 11. The sensor 60 can be permanently integrated in the housing 20, or it can be removed, e.g. be provided in an exchangeable cassette. The sensor 60 can be connected to an interface 61 on the contact surface 26 in order to transmit signals to the laser processing head 100. Alternatively, signals from the sensor 60 can be sent to a higher-level control unit of the laser processing device.

At least one sealing element (not shown) can also be arranged on the contact surface 26 in order to seal a connection between the fiber coupler and the laser processing head, the sealing element can comprise a sealing ring or O-ring which is arranged concentrically with the outlet opening 21 and surrounds the same . Furthermore, at least one electrical contact (not shown) for a safety circuit can be provided on the contact surface 26 of the fiber coupler. Alternatively, the safety circuit can be implemented using an external cable between the fiber coupler and the laser processing head.

The contact surface can therefore have at least one of the following elements, in the following preferred order from the inside to the outside:

1. Exit opening 21 for the laser beam,

2. Alignment element 27 for centering to the optical axis, e.g. centering collar or groove,

3. Sealing element, e.g. O-ring (not shown),

4. Electrical contacts for a high-power laser safety circuit (not shown),

5. Sensor interface 61 for the transmission of signals from a sensor 60 arranged in the fiber coupler to the laser processing head 100, and

6. Fastening means for mechanical locking, eg screws. The order is of course not mandatory. In particular, the radial positions of the electrical contacts for the safety circuit and the sensor interface 61 can be interchanged. The safety circuit is used to monitor the intact connection between the fiber coupler and the laser processing head in order to prevent danger from escaping or free laser radiation. The laser source, in particular a high-power laser source, is usually switched off immediately when the safety circuit is interrupted.

According to the present invention, a fiber coupler for connecting a laser light guide fiber is specified with a laser processing head, which enables a flush connection with the laser processing head. In this way, plugging processes that cause abrasion can be avoided and the risk of contamination for an optical space of the laser processing head and for a fiber end of the laser optical fiber can be reduced. In addition, the assembly of the fiber coupler, in particular a centering process, is simpler, faster and safer. The connection between the laser optical fiber and the laser processing head by the fiber coupler according to the invention is furthermore almost free of play, so that a precise, stable and firm connection is ensured. Overall, the fiber coupler according to the invention is more cost-effective to manufacture and maintain than a conventional fiber connection with a fiber socket and a fiber connector.

List of reference symbols:

1 laser optical fiber

2 fiber connectors

3 fiber socket

4 protective glass

5 aperture

33 fasteners

100 laser processing head

A centering on the optical axis

B seal

C Electrical contacts for safety circuit

D Mechanical lock

WK water cooling

10 laser optical fiber

11 fiber end

20 housing

21 outlet opening

22 fasteners

23 fasteners

24 interior

25 flange

26 contact area

27 alignment element

40 protective glass cap

44 protective glass

110 interchangeable cassette

111 protective glass

50 aperture

400 interchangeable cassette

60 sensor

61 Sensor interface

Claims

Expectations

A fiber coupler for fastening a laser optical fiber (10) to a laser processing head (100), comprising: a housing (20) with an exit opening (21) for an exit of laser light from the fiber coupler and a flange at least partially surrounding the exit opening (21) ( 25) with a contact surface (26) for attaching the fiber coupler to the laser processing head (100); and a laser optical fiber (10) with a fiber end (11), the fiber end (11) being fastened in the housing (20) in an area of the housing (20) opposite the outlet opening (21) so that from the fiber end (11) directing emerging laser light through the exit opening (21).

2. Fiber coupler according to claim 1, wherein a region of the housing (20) in which the fiber end (11) is attached and the flange (25) are formed in one piece.

3. Fiber coupler according to one of the preceding claims, wherein the contact surface (26) extends perpendicular to a laser beam propagation direction and / or perpendicular to an optical axis of the fiber end (11) and / or parallel to a light exit surface of the fiber end (11).

4. Fiber coupler according to one of the preceding claims, wherein the contact surface (26) in the laser beam propagation direction and / or along an optical axis of the fiber end (11) forms an end surface of the fiber coupler.

5. Fiber coupler according to one of the preceding claims, wherein the contact surface (26) and the outlet opening (21) lie in one plane and / or wherein the contact surface (26) and the outlet opening (21) adjoin one another.

6. Fiber coupler according to one of the preceding claims, wherein the flange (25) is provided with fastening means (22, 23) in order to fasten the fiber coupler to the laser processing head (100).

7. Fiber coupler according to one of the preceding claims, wherein the flange (25) extends radially outward from the outlet opening (21) and / or wherein the outlet opening (21) is circular.

8. Fiber coupler according to one of the preceding claims, wherein the housing (20) has an interior space (24) adjoining the outlet opening (21) and into which the fiber end (11) projects.

9. Fiber coupler according to claim 8, wherein in the interior (24) of the housing (20) a cap (40) with a protective glass (44) can be fastened so that it surrounds the fiber end (11).

10. Fiber coupler according to one of the preceding claims, wherein an interchangeable cassette (400) with a protective glass (40) is provided between the Austrittsöff voltage (21) and the fiber end (11).

11. Fiber coupler according to one of the preceding claims, wherein at least one thermal or optical sensor (60) is provided in the housing.

12. Fiber coupler according to one of the preceding claims, wherein between the Austrittsöff voltage (21) and the fiber end (11) a diaphragm (50) is provided for absorbing edge radiation of the laser beam.

13. Fiber coupler according to one of the preceding claims, wherein the housing (20) has a cooling circuit (WK) for cooling the housing (20).

14. Fiber coupler according to one of the preceding claims, wherein the flange (25) has at least one of the following elements:

- At least one sealing element for sealing between the fiber coupler and the laser processing head;

- At least one alignment element (27) for aligning the fiber coupler on the Laserbearbei processing head;

- At least one electrical contact for a safety circuit; and

- At least one interface (61) for a sensor (60) provided in the fiber coupler to the laser processing head.

15. A laser processing device, comprising: a laser processing head having a coupling surface and a coupling opening for coupling the laser beam into the laser processing head; and a fiber coupler according to one of the preceding claims, wherein the fiber coupler is attached to the laser processing head such that the contact surface of the fiber coupler is in contact with the coupling surface of the laser processing head and the exit opening of the fiber coupler is opposite the coupling opening of the laser processing head.