Fraunhofer-gesellschaft Zur Foerderung Der Angewandten Forschung E.v.

Friedrich-schiller-universitaet Jena

Friedrich-schiller-universitat Jena

Leibniz-institut Fur Photonische Technologien E.v.

Leland Stanford Junior University

Friedrich-schiller-universitat

Centre National De La Recherche Scientifique

Université De Bordeaux I

Jens Limpert

Andreas Tünnermann

César Jáuregui Misas

Tino Eidam

Fabian Stutzki

Fabian Roeser

Dirk Nodop

Damian Schimpf

Arno Klenke

Enrico Seise

Thomas Gottschall

César Jauregui Misas

Florian Jansen

Stefan Nolte

Jürgen Popp

Alexander Steinmetz

Michel J F Digonnet

Robert L Byer

Supriyo Sinha

Thomas Peschel

Andreas Tuennermann

Jens Ulrich Thomas

Ramona Eberhardt

Christoph Stihler

Michael Müller

Oliver De Vries

Thomas Schreiber

Tobias Meyer

Christian Voigtlaender

François Salin

Marco Plotner

Marco Kienel

Hans-Jürgen Otto

Hans-Juergen Otto

Christian Voigtländer

Michael Schmitt

Hans Jurgen Otto

Christian Gaida

Tobias Meyer-Zedler

Hans-Jurgen Otto

Martin Baumgartl

Roland Ackermann

Christoph Jocher

Steffen Hädrich

Steffen Böhme

César JÁUREGUI Misas

Fabian Röser

Damian N Schimpf

Jan Rothhardt

Michael MÜLLER

Marco PLÖTNER

César Misas Jauregui

César JÀUREGUI Misas

Carsten K Nielsen

Bülend Ortac

The invention relates to an optical waveguide with two or more light-guiding cores (-) extending continuously along the longitudinal extension of the optical waveguide, parallel to one another and spaced apart from one another, from one end of the optical waveguide to the other, and with a first cladding () enclosing the cores (-). It is an object of the invention to provide a multicore optical waveguide for high-power operation with reduced system complexity compared to the prior art. This object is achieved by the invention in that the cores (-) are arranged relative to one another and are spaced apart from one another in such a way that the propagation modes of the light propagating in the optical waveguide at a working wavelength couple to one another, the length of the optical waveguide being selected such that the light coupled into only a single one of the cores (-) at one end of the optical waveguide first spreads to the other cores (-) during propagation through the optical waveguide and, after passing through the optical waveguide, leaves the optical waveguide again at the other end from a single core () with at least 60%, preferably at least 75%, of the total light power propagating in the optical waveguide. The invention also relates to a laser system with such an optical waveguide as an optical amplifier, and a method for guiding light in an optical waveguide.

Optical waveguide

A device for generating laser pulses is provided, the device having an optical parametric oscillator converts the laser pulses of a pump laser to laser pulses at a signal wavelength and at an idler wavelength. The optical parametric oscillator has an optical resonator with a non-linear wavelength converter. It is an object of the invention to provide a device that makes efficient generation of synchronous laser pulse trains with two different central wavelengths possible. To this end, the invention proposes that the pump laser is tunable with respect to the pump wavelength and the repetition frequency, wherein the resonator has an optical fibre with a dispersion in the range of 10-100 ps/nm and a length of 10-1000 m. The invention furthermore relates to a method for generating laser pulses using such a device.

Device and method for generating laser pulses

The invention relates to a method for stably transmitting laser radiation through an optical waveguide (), wherein two or more modes of the laser radiation propagating in the optical waveguide () interfere and form a mode interference pattern in the optical waveguide, as a result of which a thermally induced refractive index grating is produced in the optical waveguide (). It is an object of the invention to demonstrate an effective approach for stabilizing the output signal of the optical waveguide () in a fiber-based laser/amplifier combination at high output powers, i.e. for avoiding mode instability. The invention achieves this object by virtue of the fact that a relative spatial phase shift between the mode interference pattern and the thermally induced refractive index grating is set in the direction of propagation of the laser radiation. In addition, the invention relates to a laser/amplifier combination comprising a laser () and an optical waveguide () in the form of an amplifier fiber, wherein the optical waveguide () amplifies the radiation of the laser () propagating therein. The invention proposes an actuating element (), which produces a predefinable relative spatial phase shift of the mode interference pattern and of the thermally induced refractive index grating in the direction of propagation of the laser radiation.

Avoiding mode instability in an optical amplifier fiber

An exemplary laser microscope can be provided, comprising at least one first laser source which emits at least one (e.g., pulsed) excitation beam, a scanning optical configuration (e.g., configured to scan the excitation beam over the surface of a sample), a focusing optical configuration (e.g., configured to focus the excitation beam onto the sample), and at least one detector configured to detect light emitted by the sample due to an optical effect in response to the excitation beam. A second laser source facilitates a pulsed ablation beam for a local ablation of the material of the sample. The ablation beam can be guided to the sample via the scanning and focusing optical configurations. The first and second laser sources can be fed by a mutual continuous wave pump laser and/or a mutual pulsed pump laser. The first laser source can emit pulses with at least two different wavelengths.

Laser microscope with ablation function

The invention relates to an apparatus for generating laser pulses. It is an object of the invention to provide a method for generating synchronized laser pulse trains at variable wavelengths (e.g., for coherent Raman spectroscopy/microscopy), wherein the switching time for switching between different wavelengths should be in the sub-&#x3bc;s range. For this purpose the apparatus according to the invention comprises

Generating synchronized laser pulses at variable wavelengths

The invention relates to an optical arrangement having

Optical arrangement

A method for generating a laser pulse train is provided, including at least the following method steps: generating a laser pulse train at a pulse repetition frequency; coupling the laser pulse train into an acousto-optical modulator, and selecting individual laser pulses of the laser pulse train. A system for generating a laser pulse train is also provided, including at least a pulsed laser and an acousto-optical modulator, and an associated control device.

Reducing the pulse repetition frequency of a pulsed laser system

A method of propagating a laser signal through an optical waveguide and a waveguide laser system provide a novel way of stabilizing the beam emitted by a fiber laser system above the mode instability threshold wherein the beat length of two or more interfering transverse modes of the laser signal in the optical waveguide is modulated in time.

Active stabilization of mode instabilities in optical waveguides

The invention relates to an optical waveguide () as a laser medium or as a gain medium for high-power operation, wherein the optical waveguide () is an optical fiber, the light-guiding core of which, at least in sections, is doped with rare earth ions. It is an object of the invention to provide an optical waveguide as a laser or a gain medium, and a laser/amplifier combination realized therewith, in which the output signal of the laser or gain medium is better stabilized. The invention achieves this object by virtue of the maximum small signal gain of the optical waveguide () being up to 60 dB, preferably up to 50 dB, more preferably up to 40 dB, even more preferably up to 30 dB, on account of the concentration of the rare earth ions and/or the distribution thereof in the light-guiding core. Moreover, the invention relates to the use of such an optical waveguide as an amplifier fiber () in a laser/amplifier combination.

Optical waveguide as amplifier fibre for high-performance operation

The invention relates to an optical waveguide with at least one core region () extending along the longitudinal extent of the optical waveguide, and with a first jacket () which, viewed in the cross section of the optical waveguide, surrounds the core region (). 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 ().

The invention relates to an optical array comprising a splitting element () which splits an input beam (E) into at least two partial beams (T, T, T, T), at least one optical element (V, V, V, V, MV) through which at least one of the partial beams (T, T, T, T) propagates, and at least one combining element () which spatially superimposes the partial beams (T, T, T, T) 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 () and/or the combining element () each have a partially reflective element (') which reflects the radiation of the input beam (E) or of the output beam (A) two or more times, wherein the partially reflective element (&#x2032;) has zones (a, b, c, d) of different reflectivity.

Optical array comprising a beam splitter

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

Apparatus and method for producing short radiation pulses

The invention relates to an optical amplifier arrangement for amplifying ultra-short pulsed laser radiation comprising a mode-locked laser () and two or more optical amplifiers () arranged downstream of the laser () 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 () and the optical amplifiers () at least one splitting element () which splits the pulsed laser radiation between a plurality of amplifier channels (), wherein each amplifier channel () has at least one optical amplifier (), and wherein at least one common combination element () is disposed downstream of the amplifier channels () and coherently superimposes the pulsed laser radiation amplified in the amplifier channels ().

Optical amplifier arrangement

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

Generation of azimuthally or radially polarized radiation in optical waveguides

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.

Single mode propagation in microstructured optical fibers

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Jena, Germany

Jens Limpert