Abstract: The invention relates to an optical waveguide with at least one core region (1) extending along the longitudinal extent of the optical waveguide, and with a first jacket (2) which, viewed in the cross section of the optical waveguide, surrounds the core region (1). The invention further relates to an optical arrangement with such an optical waveguide, and to a method for producing the optical waveguide. The object of the invention is to make available an optical waveguide for high-performance operation, which is improved in relation to the prior art in terms of mode instability. The invention achieves this object by virtue of the fact that the optical waveguide consists of crystalline material at least in the core region (1).

Abstract: The invention relates to an optical array comprising a splitting element (1) which splits an input beam (E) into at least two partial beams (T1, T2, T3, T4), at least one optical element (V1, V2, V3, V4, MV) through which at least one of the partial beams (T1, T2, T3, T4) propagates, and at least one combining element (4) which spatially superimposes the partial beams (T1, T2, T3, T4) in one output beam (A). The object of the invention is to provide an optical array which is improved over the prior art and which permits effective and simple splitting of the input light beam, in particular a laser beam with pulsed or continuous emission. The invention achieves this object in that the splitting element (1) and/or the combining element (4) each have a partially reflective element (2, 2?) which reflects the radiation of the input beam (E) or of the output beam (A) two or more times, wherein the partially reflective element (2, 2?) has zones (a, b, c, d) of different reflectivity.

Abstract: The invention relates to an apparatus (1) for producing short synchronous radiation pulses at different wavelengths, particularly to an optically parametric oscillator, comprising at least one pump radiation source (2), preferably a pump laser, for outputting radiation at a pump wavelength, and a resonator (3) having a wavelength-dependent effective resonator length, wherein the resonator (3) has a non-linear wavelength converter (4) for producing radiation at a first and a second wavelength; a dispersive element (5) having a strong wavelength-dependent delay characteristic; and a coupling-out element (6) for at least partially coupling-out the radiation from the resonator (3). In addition, the invention relates to a method for producing short radiation pulses by means of an apparatus (1), particularly an optically parametric oscillator.

Abstract: The invention relates to an optical amplifier arrangement for amplifying ultra-short pulsed laser radiation comprising a mode-locked laser (1) and two or more optical amplifiers (3) arranged downstream of the laser (1) in the propagation direction of the laser radiation. Optical amplifier arrangements of this type are known in the prior art. Here the intention is to present an alternative to the known amplifier arrangements. The invention proposes arranging between the laser (1) and the optical amplifiers (3) at least one splitting element (2) which splits the pulsed laser radiation between a plurality of amplifier channels (4), wherein each amplifier channel (4) has at least one optical amplifier (3), and wherein at least one common combination element (5) is disposed downstream of the amplifier channels (4) and coherently superimposes the pulsed laser radiation amplified in the amplifier channels (4).

Abstract: The invention relates to an apparatus for generating azimuthally or radially polarized radiation by means of an optical waveguide (1), wherein the optical waveguide (1) has a structure which is suitable for conducting azimuthally or radially polarized modes (5, 7). The invention proposes that the azimuthally or radially polarized modes (5, 7) in the optical waveguide (1) have different effective refractive indices and, within the optical waveguide (1), a narrow-band grating (2) is arranged, in particular a fiber Bragg grating (2) which is designed such that the spectral distance between two azimuthally or radially polarized resonant modes (5, 7) is equal to or greater than the associated spectral bandwidth.

Abstract: The invention relates to an optical fiber as an optical waveguide for the single-mode operation. The present invention proposes a fiber having a microstructure, by which the propagation of modes of a higher order are selectively suppressed in the optical waveguide. At the same time, the propagation of transversal modes of a higher order is dampened more strongly than the propagation of the fundamental modes of the optical waveguide.

Abstract: The invention relates to an optical fiber as an optical waveguide for the single-mode operation. The present invention proposes a fiber having a microstructure, by which the propagation of modes of a higher order are selectively suppressed in the optical waveguide. At the same time, the propagation of transversal modes of a higher order is dampened more strongly than the propagation of the fundamental modes of the optical waveguide.

Abstract: The invention relates to a method and corresponding devices for reducing mode instability in an optical waveguide (1), a light signal becoming unstable in the optical waveguide (1) beyond an output power threshold and energy being transformed from a basic mode into higher order modes. The invention proposes a reduction in temperature variation (2) along the optical waveguide (1) and/or a reduction in changes in the optical waveguide (1) that are caused by spatial temperature variation as a result of mode interference.

Abstract: The invention relates to an optical fiber as an optical waveguide for the single-mode operation. The present invention proposes a fiber having a microstructure, by which the propagation of modes of a higher order are selectively suppressed in the optical waveguide. At the same time, the propagation of transversal modes of a higher order is dampened more strongly than the propagation of the fundamental modes of the optical waveguide.

Abstract: The invention relates to a double-sheath fiber having a core region (1) and a sheath region, the sheath region having an inner region (2) and an outer region (3), which comprises a refractive index that is lower with respect to that of the inner region (2) and the core region (1), wherein the outer region (3) surrounds the inner region (2). The invention proposes an internal structure (4) of the inner region (2) which effects a spatial overlap of modes of higher order with the core region (1), which is lower than the spatial overlap of a fundamental mode with the core region (1).

Abstract: The invention relates to an apparatus for generation of electromagnetic radiation, having a pump light source that emits an excitation radiation at a first wavelength, and having an optical waveguide that generates frequency-converted radiation at a second and a third wavelength, by means of degenerate wave mixing, from the excitation radiation of the pump light source.

Abstract: The invention relates to a laser device (1) for amplifying and/or transporting electromagnetic radiation, comprising a radiation source (2) for generating the electromagnetic radiation and an amplifier (4) for amplifying or a medium for transporting the generated electromagnetic radiation. In order to make available a device (1) for amplifying or transporting electromagnetic radiation that provides a very easy to implement possibility for reducing the influence of non-linear effects, the electromagnetic radiation propagating in the amplifier (4) or medium is largely non-linearly polarized.

Abstract: The invention relates to a method and corresponding devices for reducing mode instability in an optical waveguide (1), a light signal becoming unstable in the optical waveguide (1) beyond an output power threshold and energy being transformed from a basic mode into higher order modes. The invention proposes a reduction in temperature variation (2) along the optical waveguide (1) and/or a reduction in changes in the optical waveguide (1) that are caused by spatial temperature variation as a result of mode interference.

Abstract: The invention relates to a laser system with a passively Q-switched laser 1, a spectrally widening element 3, and a compression element 4. Laser systems of this kind are utilized for generating ultra-short laser pulses. Systems, mode-coupled solid-state lasers known from prior art allow for generating laser pulses in the sub-10 ps range only with complicated and alignment-sensitive free-beam arrangements. Therefore, it is the object of the present invention to create a laser system that generates pulse durations of less than 10 ps and which is simple and compact to produce at the same time. In order to achieve this object, the present invention proposes that the passively Q-switched laser 1 is provided with a longitudinally monomode output radiation which is spectrally widened by means of the spectrally widening element 3 by self-phase modulation and is temporally compressed by the compression element 4.

Abstract: The invention relates to a transverse mode filter in an optical waveguide (3). The aim of the invention is to produce a transverse mode filter that permits a monolithic construction of a laser in a multi-mode waveguide. To achieve this, according to the invention the filter comprises a Fabry-Perot cavity integrated into the optical waveguide (3) and comprising two reflective elements (5) situated at a distance from one another. In addition, the waveguide (3) is modified in the region of the Fabry-Perot cavity and/or in the region of the reflective elements (5) in relation to the remaining regions of the waveguide with respect to the effective refractive index of at least one mode of the waveguide.

Abstract: The present invention relates to a device (12) and to a method for amplifying light impulses (13). The device comprises a stretcher (15) stretching the light impulses over time, at least one amplifier (16) amplifying the stretched light impulses, and a compressor (17) compressing the stretched and amplified light impulses, wherein the amplifier (16) applies a non-linear phase generated by self-phase modulation to the stretched light impulses. In order to provide a device and a method for amplifying light impulses, by means of which light impulses having higher light impulse quality and light impulse peak power can be generated, the invention proposes that means for spectrally shaping the light impulses are disposed ahead of the amplifier (16) in the beam path, wherein the means for spectrally shaping the light impulses bring about a spectral trimming of the light impulses.

Abstract: The invention relates to an apparatus for generating azimuthally or radially polarized radiation by means of an optical waveguide (1), wherein the optical waveguide (1) has a structure which is suitable for conducting azimuthally or radially polarized modes (5, 7). The invention proposes that the azimuthally or radially polarized modes (5, 7) in the optical waveguide (1) have different effective refractive indices and, within the optical waveguide (1), a narrow-band grating (2) is arranged, in particular a fibre Bragg grating (2) which is designed such that the spectral distance between two azimuthally or radially polarized resonant modes (5, 7) is equal to or greater than the associated spectral bandwidth.

Abstract: The present invention relates to a device (1, 11) for amplifying light pulses (2, 12), the device comprised of a stretcher (4, 14) which temporally stretches the light pulses (2, 12), and comprised of at least one amplifier (5, 15) which amplifies the stretched light pulses (2, 12), and comprised of a compressor (6, 16) which recompresses the stretched and amplified light pulses (2, 12), the stretcher (4, 14) and the compressor (6, 16) being dispersive elements with essentially oppositely identical dispersion. To provide a device (1, 11) for amplifying light pulses (2, 12) which is of a compact setup and which can be flexibly applied, the present invention proposes that the dispersion of the amplifier (5, 15), the dispersion of further optical elements of the device (1) and/or a mismatch of dispersion of the stretcher (4, 14) and compressor (6, 16) are at least partly compensated by self-phase modulation of the light pulses (2, 12) and/or by at least one additional element (17) of variable dispersion.

Abstract: The invention relates to a double-sheath fiber having a core region (1) and a sheath region, the sheath region having an inner region (2) and an outer region (3), which comprises a refractive index that is lower with respect to that of the inner region (2) and the core region (1), wherein the outer region (3) surrounds the inner region (2). The invention proposes an internal structure (4) of the inner region (2) which effects a spatial overlap of modes of higher order with the core region (1), which is lower than the spatial overlap of a fundamental mode with the core region (1).

Abstract: The invention relates to a Q-switched laser comprised of a pump light source (1), an optical resonator accommodating a laser medium (6), and a passive Q-switch (5). It is the object of the present invention to provide an improved Q-switched laser which is of a simple and compact setup while having the least possible jitter of the repetition time. To achieve this target, the invention proposes that by means of a beam splitter (8) part of the light coupled out of the optical resonator is passed on to an optical delay line (9) and coupled back into the optical resonator upon having passed through the optical delay line (9).