Laser system and method for operating a laser system

Abstract

Laser system (100), in particular semiconductor laser system, comprising a plurality of laser-active emitters (10), a resonator (50) for amplifying the laser beams (30) emitted by the emitters (10), and an output coupling element (24) for coupling out an output laser beam (36), wherein the resonator (50) is configured for phase coupling of the laser beams (30) and for wavelength coupling of the laser beams (30), wherein the resonator (50) has at least one first optical element (14) and at least one second optical element (16), wherein the at least one first optical element (14) is configured for phase coupling of the laser beams (30) and the at least one second optical element (16) is configured for wavelength coupling of the laser beams (30), wherein an aperture (22) is provided to select partial beams (60, 62, 64) for wavelength coupling in at least one second optical element (16), in particular wherein a selected partial beam (60, 62, 64) can be fed back via the output coupling element (24).

Description

State of the art

[0001] The invention relates to a laser system, in particular a semiconductor laser system, comprising a plurality of laser-active emitters, a resonator for the laser beams emitted by the emitters, as well as comprising an output coupling element for coupling out an output laser beam, and a method for operating a laser system.

[0002] Semiconductor-based laser systems have a structural limitation that limits their output power while maintaining good beam quality. Enlarging the structures leads to a reduction in beam quality, which is disadvantageous for many applications. However, the output power of such so-called broad-area diodes can be significantly increased. For pumping and illumination purposes, laser diodes are typically installed in linear or two-dimensional matrix-like arrangements, also called arrays, to increase the active radiation aperture and thus enable power scaling, although this typically results in a deterioration in beam quality.

[0003] There are several approaches to scaling the power of laser systems while maintaining good beam quality.

[0004] With wavelength coupling or spectral coupling of laser emitters, several laser fields with different wavelengths are typically superimposed using a dispersive element (dichroic mirror, grating, prism). The output power of these systems scales with the output power of the individual laser emitters in the laser system while simultaneously maintaining the beam quality of a single emitter. This method is used in lasers for material processing and pump light applications. Although it makes it possible to create systems close to the diffraction limit, systems are usually implemented with broad-area emitters or bars to achieve high output power. The resulting radiation has a wide frequency bandwidth, since each individual laser emitter requires its own laser frequency to enable spectral superposition.

[0005] In passive phase-coupling of laser emitters through self-assembly, lasers are driven to a common laser frequency by feedback of a split laser mode, whose wavelength matches the resonator lengths of the individual lasers involved. The resonator length must be a multiple of the wavelength. The laser frequency of the coupled system is adjusted through self-assembly, driven by gain and loss in the coupled system, similar to that in a single laser.

[0006] In active coherent phase-locking of laser emitters, individual laser fields of the same frequency (usually in a so-called master oscillator power amplifier (MOPA) or a master-slave configuration) are superimposed and their phases are independently controlled to enable constructive interference. Phase control and phase measurement can be achieved using various techniques, each with varying degrees of scalability.

[0007] DE 11 2014 004 244 B4 discloses systems and methods for beam wavelength stabilization and output beam combination in systems using so-called dense wavelength division multiplexing. A method is described for stabilizing the wavelength of the beams emitted by multiple laser emitters, the method comprising: directing the emitted beams to a first reflection diffraction element, directing a portion of the beams emitted by the first reflection diffraction element into a feedback branch as a feedback branch input, and directing a portion of the feedback branch input back through the feedback branch and into the multiple beam emitters.wherein, in directing a portion of the feedback branch input through the feedback branch, a portion of the feedback branch input is sequentially directed through a spatial filter system. Directing a portion of the feedback branch input through the feedback branch and back into the array of beam emitters comprises: directing the feedback branch input into a first arm of the feedback branch as the input to the first arm, directing the input to the first arm to a first highly reflective mirror, directing a reflection of the input to the first arm from the first highly reflective mirror to the first reflective diffraction grating as the output of the first arm, directing a reflection of the output of the first arm to a second highly reflective mirror of a second feedback arm as the input to the second arm, directing a reflection of the input to the second arm from the second highly reflective mirror to the first reflective diffraction grating as the output of the second arm,Directing a reflection of the output of the second arm into the first arm of the feedback branch as input to the first arm and directing a diffraction of the output of the first arm back into the array of beam emitters.

[0008] US 6,192,062 B1 describes an external resonator laser source having an external free-space cavity comprising a laser array, an optical element, a dispersive element, and a partially reflective element. The laser array comprises at least two optical amplification elements, each of the at least two optical amplification elements generating optical radiation having a unique wavelength. The optical element has a focal plane and is positioned to substantially align the focal plane with the at least two optical amplification elements and to collect the generated optical radiation. The dispersive element is positioned substantially in the focal plane of the optical element. The partially reflective element is positioned to collect radiation from the dispersive element.The partially reflecting element and the gain elements together form the free-space laser resonator, which defines at least the first and second wavelengths. Disclosure of the invention

[0009] An object of the invention is to provide a laser system, in particular a semiconductor laser system, which enables scaling of the power with good beam quality.

[0010] A further task is to provide a corresponding method for operating a laser system.

[0011] The objects are achieved by the features of the independent claims. Advantageous embodiments and advantages of the invention emerge from the further claims, the description, and the drawings.

[0012] The invention relates to a laser system, in particular a semiconductor laser system, comprising a plurality of laser-active emitters, a resonator for amplifying the laser beams emitted by the emitters, and an output coupling element for outputting an output laser beam. The resonator is designed for phase coupling of the laser beams and wavelength coupling of the laser beams.

[0013] The resonator has at least one first optical element and at least one second optical element, wherein the at least one first optical element is designed for the phase coupling of the laser beams and the at least one second optical element is designed for the wavelength coupling of the laser beams.

[0014] A diaphragm is provided to select partial beams for wavelength coupling in at least one second optical element.

[0015] The laser beams from the emitters are coupled via a common resonator arm, which is split between the individual emitters both spectrally via the second optical element for wavelength coupling and phase-coherently via the first optical element for phase coupling. The back of emitters, for example, designed as individual components, and the output coupling element form individual resonators for the partial beams generated by the individual emitters.

[0016] The wavelength coupling can be conveniently selected to enable the densest possible spectral coupling and to ensure that a high proportion of the power falls into the first order of the grating reflection in order to enable efficient coupling.

[0017] The phase coupling can be expediently selected such that a substantially homogeneous splitting into N partial beams emitted by emitters is achieved, where N represents the number of phase-coupled partial beams. N can be, for example, at least 10, preferably at least 50, and most preferably at least 100.

[0018] Since an aperture is provided to select partial beams for wavelength coupling in at least one second optical element, a selected partial beam can advantageously be fed back via the output coupling element.

[0019] By feeding back the selected superimposed partial beam through the output coupling element, the common mode can be selected in a simple and reliable manner with coherent phase superposition in a self-organized manner.

[0020] The functions of phase coupling and wavelength coupling can thus be conveniently distributed between the two optical elements. Diffractive optical elements, in either reflective or transmissive versions, can advantageously be used as optical elements.

[0021] The aperture enables efficient masking of partial beams of the phase-coupled laser radiation in a simple and reproducible manner.

[0022] A substantially homogeneous splitting is defined as a splitting that exhibits a deviation of approximately 10%, in particular less than 5%, from a uniform angular distribution of the partial beams. By selectively masking the partial beams of the phase superposition and the feedback of the selected superposed partial beam through the output coupling element at the resonator output, the common mode with coherent phase superposition is selected in a self-organized manner. The resonator lengths of the individual partial beams can be appropriately selected to keep the frequency separation of the common modes small and to always maintain enough common modes of the phase coupling in a desired wavelength splitting of the second optical element of the wavelength coupling.

[0023] For a more compact design, the two optical elements can be installed rotated by 90°, so that the wavelength splitting and the phase splitting take place in two planes rotated by 90°.

[0024] Wavelength coupling, also known as spectral coupling, is limited by the minimum frequency separation between the individual superimposed beams. The selection of a suitable wavelength for the optical components and the required spectral limitation for the application define a maximum frequency range of the coupled radiation. The spectral width of the individual beams and the minimum frequency separation between the individual beams thus represent a maximum upper limit for the number of beams that can be coupled.

[0025] Passive phase coupling is limited by inherent phase fluctuations within the individual emitters. Depending on the severity of these phase fluctuations, anywhere from 10 to 100 emitters can be coupled. Further scaling is currently not possible or only possible at the expense of coupling efficiency.

[0026] Optical elements suitable for wavelength coupling and / or phase coupling have surface structures on the order of magnitude of the wavelength used. Such optical elements are described, for example, in an article by H. Dammann and K. Görtler, Opt. Comm. Vol. 3(5), 1971.

[0027] The proposed combination of passive phase coupling and wavelength coupling of the laser beams, however, enables further power scaling by scaling the number of coupled emitters. The limitations of passive phase coupling and spectral wavelength coupling are reduced by the proposed combination of the two techniques, enabling scaling by several times the number of components.

[0028] While prior art approaches involving active phase coupling of laser diodes are technically scalable to multiple individual emitters, this approach is technically very complex because each individual beam requires phase control. The laser system according to the invention avoids this.

[0029] The coupling of multiple emitters without active control thus represents a significant reduction in complexity and technical effort. This enables a significantly less complex design than actively coupled systems. The proposed laser system combines the advantages of wavelength-coupled and passively phase-coupled systems, eliminating the need for additional active elements, such as those for phase measurement or phase control. Thus, the laser system is technically less complex than actively coupled systems.

[0030] The combination of passive phase coupling and wavelength coupling enables further scaling of the number of coupled emitters. This allows the number of emitters that can be coupled to be significantly increased. This reduces the scalability limitations of wavelength and passive phase coupling.

[0031] The achieved scalability allows for advantageous coupling of high-quality beam sources, thus creating high-power sources with good beam quality. High-power sources with wavelength coupling are usually limited by the beam quality of the individual emitters, which can be unfavorable due to the poor scalability of the coupling. Typical beam qualities of "good" emitters that are to be scaled to high power by coupling, or existing high-power emitters, can be achieved with M 2 =1 and 1 µm wavelength are 0.3 mm*mrad and are known to result from the focus size w0 (1 / e-radius) and half the divergence angle θ of the radiation. M 2 represents the diffraction index that characterizes the laser beam.

[0032] The laser system according to the invention can comprise semiconductor laser emitters, which can have a variety of emitter structures. For example, the emitters of the laser system can consist of a plurality of semiconductor diodes on or in a substrate, be designed as diode bars, or as tapered lasers.

[0033] In a diode bar, also called a bar structure, individual emitters are combined on a strip-shaped chip. Several such bars can be combined to form a stack (bar stack).

[0034] A tapered laser is formed from a laterally single-mode ridge waveguide section and a trapezoidal section in which the laser radiation is amplified.

[0035] According to an advantageous embodiment of the laser system, the resonator can be split and, in particular, can have at least one first resonator arm and an adjoining second resonator arm between the plurality of emitters and the output coupling element. Advantageously, the first resonator arm can comprise the phase-coupling region with the first optical element between the emitters and the second optical element, while the second resonator arm comprises the wavelength-coupling region between the second optical element and the output coupling element.

[0036] According to an advantageous embodiment of the laser system, the second resonator arm can be terminated on the output side by the output coupling element. In particular, when used as intended, the second resonator arm can have both a phase-locked and a wavelength-locked laser beam.

[0037] According to an advantageous embodiment of the laser system, the second resonator arm can be terminated on the output side by the output coupling element. In particular, the second resonator arm can be formed between the output coupling element and the at least one second optical element.

[0038] According to an advantageous embodiment of the laser system, the resonator can comprise a resonator arm with individual resonators between the plurality of emitters and the output coupling element. The respective path between the rear side of one of the emitters and the output coupling element forms the individual resonator of the respective emitter.

[0039] According to an advantageous embodiment of the laser system, the individual resonators can have different resonator lengths. The resonator lengths of the individual resonators can be expediently selected to be different in order to keep the frequency separation of the common modes small and always maintain a sufficient number of common modes of phase coupling in a desired wavelength split of the second optical element of the wavelength coupling. Nevertheless, the wavelength coupling can expediently be selected to enable the densest possible spectral wavelength coupling and a high proportion of the power falls into the first order of a grating reflection of the second optical element. This enables efficient coupling.

[0040] According to an advantageous embodiment of the laser system, the at least one second optical element can be configured such that at least 50% of the laser power lies in a first order of grating reflection, preferably at least 70%, and most preferably at least 90% of the laser power lies in a first order of grating reflection. The wavelength coupling can thus be expediently selected to enable the densest possible spectral wavelength coupling and a high proportion of the power falls into the first order of grating reflection to enable efficient coupling.

[0041] According to an advantageous embodiment of the laser system, the at least one first optical element can be designed such that a substantially homogeneous splitting into at least a number N of partial beams takes place, wherein N is at least 5, preferably at least 20, very particularly preferably at least 50.

[0042] By selectively masking out partial beams of the phase superposition, which is advantageously possible due to the large number of partial beams, and by feeding back the selected superimposed partial beam through the output coupling element, the common mode with coherent phase superposition can be selected in a self-organized manner.

[0043] According to an advantageous embodiment of the laser system, the at least one second optical element can be designed such that a substantially homogeneous splitting into at least a number M of partial beams takes place, where M is at least 5, preferably at least 50, most preferably at least 100. The number of partial beams can expediently be selected such that the densest possible spectral wavelength coupling is enabled.

[0044] According to an advantageous embodiment of the laser system, an optically active plane of the at least one first optical element and an optically active plane of the at least one second optical element can be arranged offset by 90° from each other. For a more compact design, the two optical elements can, for example, be installed rotated by 90°, so that the wavelength splitting and the phase splitting occur in two planes rotated by 90°.

[0045] According to an advantageous design of the laser system, the plurality of laser-active emitters can be arranged in a linear arrangement. Such arrangements are commonly referred to as arrays. By integrating the individual emitters into a compact array, the highest possible packing density of the laser system can be achieved, which is particularly advantageous for pumping or illumination purposes.

[0046] According to an advantageous embodiment of the laser system, the plurality of laser-active emitters can be arranged in the form of a bar structure, in particular in the form of a stacked bar structure. By integrating the individual emitters in the form of a bar structure, in particular in the form of a stacked bar structure, the highest possible packing density of the laser system can be achieved, which is particularly advantageous for pumping or illumination purposes.

[0047] According to an advantageous embodiment of the laser system, the plurality of laser-active emitters can be arranged in an integrated solid-state component. By integrating the emitters into a single integrated solid-state component, the highest possible packing density of the laser system can be achieved, which is particularly advantageous for pumping or illumination purposes.

[0048] According to an advantageous embodiment of the laser system, the at least one first optical element and / or the at least one second optical element can comprise at least one of a dichroic mirror and / or a grating and / or a prism. Such optical elements can be advantageously used for the inventive functions of phase coupling and / or wavelength coupling.

[0049] According to a further aspect of the invention, a method for operating a laser system according to the invention is proposed, in which a plurality of laser-active emitters emit laser beams that are amplified in a resonator and coupled out by an output coupling element, wherein the resonator effects phase coupling of the laser beams and wavelength coupling of the laser beams. The laser beams are amplified in at least one resonator arm to form a phase-coupled and wavelength-coupled laser beam, wherein partial beams for wavelength coupling are selected in at least one second optical element via an aperture. In particular, a selected partial beam can be fed back via the output coupling element.

[0050] The combination of passive phase coupling and wavelength coupling of the laser beams enables further scaling of the power by scaling the number of coupled emitters. The limitations of passive phase coupling and spectral coupling are reduced by combining the techniques, enabling scaling by several times the number of components.

[0051] By combining spectral and passive coupling, scalability can be significantly increased. The limitations of passive coupling and wavelength coupling are thus circumvented. The combination of passive coupling and wavelength coupling further enables scaling of the number of coupled emitters. This allows the number of coupled elements to be significantly increased. This reduces the limitations of wavelength and passive coupling scalability.

[0052] Due to the high scalability, beam sources with high beam quality can be advantageously coupled, thus creating a high-power source with good beam quality. High-power sources with wavelength coupling are usually limited by the beam quality of the emitters, which can be degraded due to the poor scalability of phase coupling. Typical beam qualities of "good" emitters that are to be scaled to high power by coupling, or existing high-power emitters, can be achieved at M 2 =1 and 1 µm wavelength is 0.3 mm*mrad and results from the focus size w0 (1 / e-radius) and half the divergence angle θ of the radiation. M 2 represents the diffraction index that characterizes the laser beam.

[0053] The emitters are coupled via the common resonator arm, which is distributed between the emitters both spectrally via the second optical element for wavelength coupling and phase-coherently via the first optical element for phase coupling. The back of the emitters and the output coupling element each form individual resonators for the individual emitters.

[0054] According to an advantageous embodiment of the method, a substantially homogeneous splitting into at least a number N of partial beams can take place at at least one first optical element, where N is at least 5, preferably at least 20, and most preferably at least 50. The phase coupling can expediently be selected such that a substantially homogeneous splitting into N partial beams is achieved, where N represents the number of phase-coupled partial beams. By selectively blocking partial beams of the phase superposition and the feedback of the selected superposed partial beam by the output coupling element, the common mode with coherent phase superposition is selected in a self-organized manner.

[0055] According to an advantageous embodiment of the method, a substantially homogeneous splitting into at least a number M of partial beams can be carried out on at least one second optical element, where M is at least 5, preferably at least 50, very particularly preferably at least 100. The number of possible partial beams can expediently be selected such that the densest possible spectral wavelength coupling is enabled.

[0056] According to an advantageous embodiment of the method, a proportion of the first-order laser power of the grating reflection at the at least one second optical element can be at least 50%, preferably at least 70%, particularly preferably at least 90%. The wavelength coupling can thus be expediently selected to enable the densest possible spectral coupling and a high proportion of the power falls into the first order of the grating reflection to enable efficient coupling.

[0057] According to an advantageous embodiment of the method, the phase coupling of the laser beams can take place in the at least one first optical element of the resonator and the wavelength coupling of the laser beams can take place in the at least one second optical element. The functions of phase coupling and wavelength coupling can thus be expediently distributed between the two optical elements. Diffractive, but also transmissive optical elements can advantageously be used as optical elements. The individual emitters are coupled via the common resonator arm, which is distributed between the emitters both spectrally via the second optical element of the wavelength coupling and phase-coherently via the first optical element of the phase coupling. drawing

[0058] Further advantages will become apparent from the following description of the drawings. The figure illustrates an embodiment of the invention. The figure, the description, and the claims contain numerous features in combination. Those skilled in the art will also expediently consider the features individually and combine them into useful further combinations.

[0059] The single figure shows an example: Fig. 1 a schematic representation of a laser system according to an embodiment of the invention. Embodiment of the invention

[0060] The figure shows only an example and is not to be understood as limiting.

[0061] The directional terminology used below, including terms such as "left," "right," "top," "bottom," "before," "behind," "after," and the like, is intended solely to enhance understanding of the figures and is in no way intended to limit the scope of the invention. The components and elements depicted, as well as their design and use, may vary according to the considerations of a person skilled in the art and may be adapted to specific applications.

[0062] Fig. 1 shows a schematic representation of a laser system 100 according to an embodiment of the invention with first and second optical elements 14, 16.

[0063] The laser system 100, which can be designed in particular as a semiconductor laser system, comprises a plurality of laser-active emitters 10, a resonator 50 for amplifying the laser beams 30 emitted by the emitters 10, and an output coupling element 24 for outputting an output laser beam 36. The resonator 50 is designed for phase coupling of the laser beams 30 and for wavelength coupling of the laser beams 30. The emitters 10 are arranged linearly in individual arrays 40, 42, 44. The plurality of laser-active emitters 10 can expediently be arranged in an integrated solid-state component in order to achieve the most compact design possible.

[0064] The resonator 50, which is common to the laser beams 30 of the emitters 10, has a first optical element 14 and a common second optical element 16 for each array 40, 42, 44, wherein the respective first optical element 14 is designed for phase coupling of the laser beams 30 and the second optical element 16 is designed for wavelength coupling of the laser beams 30. The laser beams 30 of each emitter 10 are imaged onto the respective first optical element 14 by means of an imaging optics 12 assigned to a respective array 40, 42, 44. The respective first optical element 14 and / or the second optical element 16 can be designed, for example, as a dichroic mirror and / or a grating and / or a prism.

[0065] The resonator 50 is split and, in particular, has at least one first resonator arm 52 and an adjoining second resonator arm 54 between the plurality of emitters 10 and the output coupling element 24. The first resonator arm 52 extends from the emitters 10 to the second optical element 16. The second resonator arm 54 is formed between the output coupling element 24 and the one second optical element 16 and is terminated on the output side by the output coupling element 24. In particular, when used as intended, the second resonator arm 54 has a laser beam 34 that is both phase-coupled and wavelength-coupled.

[0066] The first resonator arm 52 comprises individual resonators 56, which are formed between the plurality of emitters 10 and the decoupling element 24.

[0067] The respective first optical element 14 is designed such that a substantially homogeneous splitting into at least a number N of partial beams 32 takes place, where N can be at least 5, preferably at least 20, most preferably at least 50. In the Fig. In the embodiment shown in Figure 1, each array 40, 42, 44 of emitters has a number N=5 of individual emitters.

[0068] A diaphragm 22 is provided downstream of the first optical element 14 to select partial beams 32 as phase-coupled partial beams 60, 62, 64 for wavelength coupling in at least one second optical element 16. A selected partial beam 60, 62, 64 can be fed back via the output coupling element 24.

[0069] In the illustrated laser system 100, the second optical element 16 is configured for a number M=3 at selected partial beams 60, 62, 64.

[0070] The plurality of laser-active emitters 10 of the laser system 100 emits laser beams 30, which are amplified in the resonator 50 and coupled out by the output coupling element 24, wherein the resonator 50 effects phase coupling of the laser beams 30 and wavelength coupling of the laser beams 30. At the respective first optical element 14, a substantially homogeneous splitting into at least the number N of partial beams 32 takes place. Partial beams 32 are selected via the apertures 22, and the selected partial beam 60, 62, 64 is imaged onto the second optical element 16. The phase coupling of the laser beams 30 takes place in the respective first optical element 14 of the resonator 50, and the wavelength coupling of the laser beams 30 takes place in the second optical element 16.The laser beams 30 are amplified in the resonator arm 54 to a phase-coupled and wavelength-coupled laser beam 34 and coupled out via the coupling element 24 in an outcoupling laser beam 36.

[0071] The one second optical element 16 is designed such that a proportion of at least 50% of the laser power lies in a first order of grating reflection, preferably of at least 70%, very particularly preferably of at least 90% of the laser power lies in a first order of grating reflection.

[0072] The coupling of the laser beams 30 of the emitters 10 thus occurs via the common resonator arm 52, which is distributed between the emitters 10 both spectrally via the second optical element 16 of the wavelength coupling and phase-coherently via the first optical element 14 of the phase coupling. The rear side 26 of the emitters 10 and the output coupling element 24 form the individual resonators 56 of the emitters 10. The wavelength coupling can be expediently selected to enable the densest possible spectral coupling and a high proportion of the power falls into the first order of the grating reflection to enable efficient coupling.

[0073] The phase coupling can be expediently selected such that a substantially homogeneous splitting into the N partial beams 32 is achieved. By selectively masking partial beams 32 of the phase superposition and the feedback of the selected superposed partial beam 60, 62, 64 by the output coupling element 24, the common mode with coherent phase superposition is selected in a self-organized manner. The resonator lengths of the individual resonators 56 can be expediently selected differently in order to keep the frequency spacing of the common modes small and to always obtain enough common modes of the phase coupling in a desired wavelength splitting of the second optical element 16 of the wavelength coupling. For a more compact design, the two optical elements 14, 16 can, for example, be installed rotated by 90°, so that the wavelength splitting and the phase splitting take place in two planes rotated by 90°. Reference symbol 10 emitters 12 Imaging optics 14 Phase coupling element 16 wavelength coupling element 22 aperture 24 decoupling element 26 Back of emitter 30 laser beams 32 partial beams 34 coupled laser beam 36 Output laser beam 40 arrays 42 arrays 44 arrays 50 resonators 52 Resonator arm 54 Resonator arm 56 single resonators 60 partial beams 62 partial beams 64 partial beams 100 laser system

Claims

[1] Laser system (100), in particular semiconductor laser system, comprising a plurality of laser-active emitters (10), a resonator (50) for amplifying the laser beams (30) emitted by the emitters (10), and a coupling-out element (24) for coupling out an output laser beam (36), wherein the resonator (50) is designed for phase coupling of the laser beams (30) and for wavelength coupling of the laser beams (30), wherein the resonator (50) has at least one first optical element (14) and at least one second optical element (16), wherein the at least one first optical element (14) is designed for the phase coupling of the laser beams (30) and the at least one second optical element (16) is designed for the wavelength coupling of the laser beams (30), wherein a diaphragm (22) is provided to select partial beams (60, 62, 64) for the wavelength coupling in the at least one second optical element (16), in particular wherein a selected partial beam (60, 62, 64) can be fed back via the coupling-out element (24). [2] Laser system according to claim 1, wherein the resonator (50) is divided and in particular has at least one first resonator arm (52) and an adjoining second resonator arm (54) between the plurality of emitters (10) and the coupling-out element (24). [3] Laser system according to claim 2, wherein the second resonator arm (54) is closed on the output side by the coupling-out element (24), in particular wherein, when used as intended, the second resonator arm (54) has a laser beam (34) that is both phase-coupled and wavelength-coupled. [4] Laser system according to claim 2 or 3, wherein the second resonator arm (54) is closed on the output side by the coupling-out element (24), in particular wherein the second resonator arm (54) is formed between the coupling-out element (24) and the at least one second optical element (16). [5] Laser system according to one of the preceding claims, wherein the resonator (50) comprises a resonator arm (52) with individual resonators (56) between the plurality of emitters (10) and the coupling-out element (24), in particular wherein the individual resonators (56) have different resonator lengths. [6] Laser system according to one of the preceding claims, wherein the at least one second optical element (16) is designed such that a proportion of at least 50% of the laser power lies in a first order of grating reflection, preferably of at least 70%, very particularly preferably of at least 90% of the laser power lies in a first order of grating reflection. [7] Laser system according to one of the preceding claims, wherein the at least one first optical element (14) is designed such that a substantially homogeneous splitting into at least a number N of partial beams (32) takes place, wherein N is at least 5, preferably at least 20, most preferably at least 50. [8] Laser system according to one of the preceding claims, wherein the at least one second optical element (16) is designed such that a substantially homogeneous splitting into at least a number M of partial beams (60, 62, 64) takes place, wherein M is at least 5, preferably at least 50, most preferably at least 100. [9] Laser system according to one of the preceding claims, wherein an optically active plane of the at least one first optical element (14) and an optically active plane of the at least one second optical element (16) are arranged offset by 90° from one another. [10] Laser system according to one of the preceding claims, wherein the plurality of laser-active emitters (10) is arranged in the form of a linear arrangement (40, 42, 44), in particular wherein the plurality of laser-active emitters (10) is arranged in the form of a bar structure, in particular in the form of a stacked bar structure. [11] Laser system according to one of the preceding claims, wherein the plurality of laser-active emitters (10) are arranged in an integrated solid-state component. [12] Laser system according to one of the preceding claims, wherein the at least one first optical element (14) and / or the at least one second optical element (16) comprises at least one of a dichroic mirror and / or a grating and / or a prism. [13] Method for operating a laser system (100) according to one of the preceding claims, wherein a plurality of laser-active emitters (10) emit laser beams (30) which are amplified in a resonator (50) and coupled out by a coupling-out element (24), wherein the resonator (50) effects a phase coupling of the laser beams (30) and a wavelength coupling of the laser beams (30), wherein the laser beams (30) are amplified in at least one resonator arm (54) to form a phase-coupled and wavelength-coupled laser beam (34), wherein partial beams (60, 62, 64) for wavelength coupling in at least one second optical element (16) are selected via a diaphragm (22), in particular wherein a selected partial beam (60, 62, 64) is fed back via the decoupling element (24). [14] Method according to claim 13, wherein at least one first optical element (14) is subjected to a substantially homogeneous splitting into at least a number N of partial beams (32), wherein N is at least 5, preferably at least 20, most preferably at least 50. [15] Method according to one of claims 13 or 14, wherein a substantially homogeneous splitting into at least a number M of partial beams (60, 62, 64) takes place at at least one second optical element (16), wherein M is at least 5, preferably at least 50, most preferably at least 100. [16] Method according to one of claims 13 to 15, wherein a proportion of the first-order laser power of the grating reflection at the at least one second optical element (16) is at least 50%, preferably at least 70%, particularly preferably at least 90%. [17] Method according to one of claims 13 to 16, wherein the phase coupling of the laser beams (30) takes place in the at least one first optical element (14) of the resonator (50) and the wavelength coupling of the laser beams (30) takes place in the at least one second optical element (16).

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