Mainz, Germany

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Piccoli R.,University of Swansea | Piccoli R.,University of Pavia | Robin T.,IXFiber S.A.S. | Brand T.,Dilas Diodenlaser GmbH | And 2 more authors.
Optics Express | Year: 2014

Al-silicate fibers have excellent manufacturing quality. Unfortunately, high-Yb doping concentration may be limited by severe losses induced by photodarkening phenomenon. In this paper we demonstrate for the first time that Al-silicate Yb-doped fibers with highinversion and doping concentration above 1 wt% can be successfully used by implementing a simple optical bleaching scheme. A co-injection into the active fiber of a few mW of light at around 550 nm wavelength successfully eliminates almost all photodarkening induced losses. We demonstrate operation at above 90% of the pristine output power level in several lasers with up to 30% Yb ions in the excited state. These results may allow to use Yb-doped Al-silicate fibers with doping level increased by one order of magnitude. Finally, we provide a comprehensive picture of main parameters affecting photobleaching performance and, to the best of our knowledge, we report the first quantitative measurement of the Ytterbium excited state absorption cross-section in the visible range. © 2014 Optical Society of America.


Grant
Agency: Cordis | Branch: FP7 | Program: CP | Phase: FoF-ICT-2011.7.1 | Award Amount: 4.33M | Year: 2012

The BRIDLE project seeks to harness the power and efficiency of diode lasers to develop an affordable direct diode laser source for industrial applications requiring the cutting and welding of sheet metal. Specifically, BRIDLEs diode laser will have a power >2kW from a 100um diameter (NA <= 0.15) optical fibre and efficiency >40%. (This is ~2.5x more powerful, 10x brighter and 1.7x more efficient than the best spectral beam combined diode laser and ~30x times brighter than conventional diode lasers.) BRIDLE will focus on technologies suitable for manufacturability and cost scaling. Along with the increased power and brilliance, this will enable direct diode lasers to penetrate the metal processing market.\n\nBRIDLEs approach is modular, scalable and forward compatible. It begins with high brilliance mini-bars, whose emitters use intracavity filters to achieve 2-3x higher brilliance (~7W @ 0.8-1.5mm.mrad) than the best broad-area emitters (~7W @ 2.7mm.mrad). Fine and coarse spectral beam combining will further increase the brilliance by 5x and 3x increasing the total brilliance by 30-40x. Advanced coherent beam combining techniques will also be pursued to develop phase-coupled mini-bars with a nearly diffraction limited output power of 30W, allowing a further >4x improvement in spatial and spectral brilliance.\n\nBRIDLEs approach is chosen to be compatible with manufacturability and cost scaling requirements. The cost and complexity of the optical system are reduced by integrating optics inside the mini-bars (e.g. mode filters, DBR gratings for fine wavelength-spacing). Efficient, extremely low vertical divergence structures will lead to low-cost smile-insensitive assembly and low-loss optical coupling. The chosen packaging and beam combining techniques allow simple fabrication and good thermal management.\n\nBRIDLEs laser system will be validated for sheet metal cutting. The constituent sub-modules will target additional applications and markets.\n\nThe objectives of the BRIDLE project are of central importance to the photonics and manufacturing industries in Europe. BRIDLE technologies will enable the European diode laser and laser systems industries to maintain a leading global position. The industrial impact will extend across a wide range of industrial sectors, with European applications of this technology in the automotive, aerospace, manufacturing and materials processing sectors giving European manufacturers new advantages in an increasingly dynamic and competitive economic climate.\n\nThrough the exciting new technologies developed in this project, the European laser diode industry will be able to introduce new direct diode lasers into the materials processing markets at a lower cost and with significantly improved performance. European industry and society will be the first to benefit. The BRIDLE project will play a direct and important role in reinforcing economic growth, competitiveness, employment and sustainability.


Grant
Agency: Cordis | Branch: FP7 | Program: CP-IP | Phase: NMP-2008-4.0-4 | Award Amount: 15.74M | Year: 2009

The LIFT project will establish international leadership for Europe in the science, application and production technologies for material processing by fibre lasers through the development of innovative laser sources. Major advances beyond the state of the art are planned: The cold-ablation fibre laser, based on ultra-short pulses, will open an entirely new market (100 mill. p.a.) for laser processing of ceramics. The extreme high-power fibre laser will enlarge the EUV lithography market (500 mill. p.a.) to include fibre lasers. The visible RGB fibre laser will produce the first high-brilliance source for laser projection displays (15 mill. p.a.). New future-oriented manufacturing tools based on higher-power pulsed fibre lasers (80 mill. p.a.). The high-reliability laser for large-scale manufacturing with High Speed Laser Remote Processing - means a new level of performance for 2kWatt materials-processing lasers with raised MTBF to 50.000 hours (accessible market 1 bill. p.a.). The Horizontal integration and networking in Europes high brilliance laser industry in this project will enable a greater market share for existing applications, create new areas of exploitation for manufacturing, and build a European network of component suppliers, laser manufacturers, universities and research institutes. As a result, LIFT will cause the following results to emerge: 1. Europe would take advantage of novel laser sources to be employed for various processing applications, many of which cannot even be treated by todays lasers. 2. European companies will benefit by the exploitation of the knowledge by the LIFT consortium in the field of fibre lasers, thus creating new markets and improving productivity in existing ones, thus building the competitiveness and the technological role of Europe; 3. The society as a whole would benefit from the results of LIFT, because in many sectors the further development of laser processing is crucial for the improvement of the quality


Reinl S.,Dilas Diodenlaser GmbH
Physics Procedia | Year: 2013

Aside from conventional welding methods, laser welding of plastics has established itself as a proven bonding method. The component-conserving and clean process offers numerous advantages and enables welding of sensitive assemblies in automotive, electronic, medical, human care, food packaging and consumer electronics markets. Diode lasers are established since years within plastic welding applications. Also, soft soldering using laser radiation is becoming more and more significant in the field of direct diode laser applications. Fast power controllability combined with a contactless temperature measurement to minimize thermal damage make the diode laser an ideal tool for this application. These advantages come in to full effect when soldering of increasingly small parts in temperature sensitive environments is necessary. © 2013 The Authors.


Unger A.,Dilas Diodenlaser GmbH | Kuster M.,Dilas Diodenlaser GmbH | Kohler B.,Dilas Diodenlaser GmbH | Biesenbach J.,Dilas Diodenlaser GmbH
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

Diode lasers in the blue and red spectral range are the most promising light sources for upcoming high-brightness digital projectors in cinemas and large venue displays. They combine improved efficiency, longer lifetime and a greatly improved color space compared to traditional xenon light sources. In this paper we report on high-power visible diode laser sources to serve the demands of this emerging market. A unique electro-optical platform enables scalable fiber coupled sources at 638 nm with an output power of up to 100 W from a 400 μm NA0.22 fiber. For the blue diode laser we demonstrate scalable sources from 5 W to 100 W from a 400 μm NA0.22 fiber. © Copyright SPIE 2013.


Wolf P.,Dilas Diodenlaser GmbH | Kohler B.,Dilas Diodenlaser GmbH | Rotter K.,Dilas Diodenlaser GmbH | Hertsch S.,Dilas Diodenlaser GmbH | And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

New solid-state laser devices, especially fiber laser systems, require increasingly higher optical pump power provided by fiber-coupled diode laser modules. In particular for defense technology, robust but lightweight high-power diode laser sources with high brightness are needed. We have developed a novel diode laser device combining high power, high brightness, wavelength stabilization and low weight, which becomes more and more important for a multitude of applications. Heart of the device is a specially tailored laser bar, which epitaxial and lateral structure is designed such that only standard fast- and slow-axis collimator lenses are required to couple the beam into a 200 μm fiber with numerical aperture of 0.22. In this paper we present a detailed characterization of the new diode laser device with up to 775 W of optical power coupled into a 200 μm, NA 0.22 fiber. One important feature of the device is a lightweight design due to a special housing optimized for low weight. In addition we present results of a diode laser device with 675 W of optical output power and improved spectral quality, which is ensured over a wide range of temperature and current by means of volume holographic gratings for wavelength stabilization. For this device an overall efficiency of more than 42.5 % has been achieved. Furthermore we present a compact diode laser source with 230 W of optical power coupled into a 200 μm, NA 0.22 fiber. This diode laser device is optimized with regard to highest efficiency and yields an overall electro-optical efficiency of more than 50 %.


Horn W.,Dilas Diodenlaser GmbH
Key Engineering Materials | Year: 2010

Diode lasers have become an important tool for polymer welding in automotive industries, in medical and electronics manufacturing. High efficiency and well fitting beam quality make them a perfect tool for industrial applications. With adapted optics it is possible to fit the laser spot shape to the geometry of the work piece. Galvo scanners are the most flexible tool to apply local and precise dose of heat to the work piece. If this flexibility is not needed, the laser spot can be customized by optics to line, circular or arbitrary shaped geometries. For joining transparent parts either an absorbing layer or diode lasers with a wavelength of 1940 nm can be used. © (2010) Trans Tech Publications.


Gilly J.,m2k laser GmbH | Friedmann P.,m2k laser GmbH | Kissel H.,Dilas Diodenlaser GmbH | Biesenbach J.,Dilas Diodenlaser GmbH | Kelemen M.T.,m2k laser GmbH
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

In diode laser applications for fibre laser pumping and materials processing high brightness becomes more and more important. At the moment fibre coupled modules benefit from continuous improvement of Broad-Area (BA) lasers on the chip level regarding output power, efficiency and far-field characteristics. To achieve high brightness not only the output power must be increased, but also the far field angles have to be maintained or even decreased because brightness is proportional to output power divided by beam quality. Typically fast axis far fields show mostly a current independent behaviour, for broad-area lasers far-fields in the slow axis suffer from a strong current and temperature dependence, limiting the brightness. These limitations can be overcomed by carefully optimizing epitaxy-design and processing and also thermal management of the mounted device. The easiest way to achieve a good thermal management of BA-Lasers is to increase the resonator length while simultaneously decreasing internal losses of the epitaxy structure. To fulfill these issues, we have realized MBE grown InGaAs/AlGaAs broad-area with resonator lengths between 4mm and 6mm emitting at 976nm. To evaluate the brightness of these broad-area lasers single emitters have been mounted p-side down. Near- and far-fields have been carefully investigated. For a 4mm long broad-area laser with around 100μm emission width a beam parameter product of less than 3.5 mm x mrad has been achieved at 10W with a slope efficiency of more than 1.1W/A and a maximum wall-plug efficiency of more than 67%. For a device with 6mm resonator length we have reached a BPP of less than 3.5mm x mrad at 14W in slow axis direction which results in a brightness around 130MW/cm 2 sr, which is to our knowledge the highest brightness reported so far for BA-lasers. © 2012 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).


Kissel H.,Dilas Diodenlaser GmbH | Kohler B.,Dilas Diodenlaser GmbH | Biesenbach J.,Dilas Diodenlaser GmbH
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

We present performance data of recent high-power laser diodes emitting at typical pump wavelengths for alkali vapor lasers: 852 nm for cesium, 780 nm for rubidium, 766 nm for potassium, and 670 nm for lithium atoms. Due to different approaches in alkali laser systems, we report on usual pumps at these non-standard wavelengths with typical line widths of a few nm used for collisional and pressure broadened gas absorption lines as well as on wavelength stabilized laser diodes using volume Bragg gratings (VBGs) for systems with narrow gas absorption lines. The detailed characterization of laser diodes available at DILAS includes power, efficiency, spectral data, and life time results. While bars at 6xx and 7xx nm are limited in optical output power due to the strong in-built strain, especially the bars at 852 nm with a small inbuilt strain have the biggest potential in terms of pump power. The power conversion efficiency in cw operation is as high as 60% at 100 W. Higher power and operation at increased heat sink temperatures up to 50°C are possible depending on lifetime requirements. © 2012 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).


Neukum J.,Dilas Diodenlaser GmbH
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

Diode lasers have a broad wavelength range, from the visible to beyond 2.2μm. This allows for various applications in the defense sector, ranging from classic pumping of DPSSL in range finders or target designators, up to pumping directed energy weapons in the 50+ kW range. Also direct diode applications for illumination above 1.55μm, or direct IR countermeasures are of interest. Here an overview is given on some new wavelengths and applications which are recently under discussion. In this overview the following aspects are reviewed: • High Power CW pumps at 808 / 880 / 940nm • Pumps for DPAL - Diode Pumped Alkali Lasers • High Power Diode Lasers in the range < 1.0 μm • Scalable Mini-Bar concept for high brightness fiber coupled modules • The Light Weight Fiber Coupled module based on the Mini-Bar concept Overall, High Power Diode Lasers offer many ways to be used in new applications in the defense market. © 2012 SPIE.

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