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Projects / Programmes source: ARIS

Frequency doubled pulsed fiber laser for industry and medicine.

Research activity

Code Science Field Subfield
2.21.00  Engineering sciences and technologies  Technology driven physics   

Code Science Field
T165  Technological sciences  Laser technology 

Code Science Field
2.11  Engineering and Technology  Other engineering and technologies 
Keywords
fiber lasers, gain switching, laser, optical fiber, laser application
Evaluation (rules)
source: COBISS
Researchers (21)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  32091  PhD Vid Agrež  Technology driven physics  Researcher  2011 - 2014  86 
2.  11905  PhD Aleš Babnik  Manufacturing technologies and systems  Researcher  2011 - 2012  103 
3.  18327  PhD Drago Bračun  Manufacturing technologies and systems  Researcher  2011  236 
4.  04107  PhD Janez Diaci  Manufacturing technologies and systems  Researcher  2011 - 2012  363 
5.  06502  Aleš Dolžan  Systems and cybernetics  Researcher  2011  28 
6.  14440  PhD Andrej Horvat  Manufacturing technologies and systems  Researcher  2011 - 2012  12 
7.  10926  PhD Darja Horvat  Manufacturing technologies and systems  Researcher  2011  64 
8.  11228  PhD Rok Hrovatin  Metrology  Researcher  2011 - 2012  47 
9.  21238  PhD Matija Jezeršek  Manufacturing technologies and systems  Researcher  2011  375 
10.  24380  PhD Blaž Kmetec  Technology driven physics  Researcher  2011 - 2014 
11.  12054  PhD Drago Kovačič  Manufacturing technologies and systems  Researcher  2011 - 2014  129 
12.  25626  PhD Klemen Kunstelj  Physics  Researcher  2011 - 2012  25 
13.  11742  PhD Marko Marinček  Physics  Researcher  2011 - 2014  59 
14.  01649  PhD Janez Možina  Manufacturing technologies and systems  Researcher  2011 - 2014  641 
15.  15646  PhD Rok Petkovšek  Manufacturing technologies and systems  Head  2011 - 2014  273 
16.  12752  PhD Boštjan Podobnik  Physics  Researcher  2011 - 2014  62 
17.  33892  PhD Klemen Povšič  Systems and cybernetics  Technical associate  2011 - 2013  19 
18.  25463  PhD Tomaž Požar  Manufacturing technologies and systems  Researcher  2011 - 2014  146 
19.  24276  PhD Andrej Vrečko  Physics  Researcher  2011 - 2013  30 
20.  18955  MSc Matjaž Zalar  Systems and cybernetics  Researcher  2011 - 2014 
21.  24453  PhD Janez Žabkar  Electronic components and technologies  Researcher  2011 - 2014  13 
Organisations (4)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0143  Fotona proizvodnja optoelektronskih naprav d.o.o. (Slovene)  Ljubljana  5045223000  894 
2.  0782  University of Ljubljana, Faculty of Mechanical Engineering  Ljubljana  1627031  29,201 
3.  1617  OPTOTEK razvoj in proizvodnja optične in laserske opreme d.o.o. (Slovene)  Ljubljana  5326389  32 
4.  7741  LPKF LASER & ELECTRONICS d.o.o. (Slovene)  Naklo  5711096  314 
Abstract
Remarkable progress in the areas of active optical fibers and pump diodes in recent years allows the development of many new types of fiber lasers, which are distinguished by compactness, robustness, energy efficiency and high quality output beam. The research and development in these areas is dominated by the world's largest manufacturers with strong development and production departments (IPG, SPI Lasers, Coherent, JDSU, ...) which are often inflexible for the specific needs of small and medium-sized manufacturers of laser systems. Slovenian laser industry (LPKF, Fotona, Optotek) in collaboration with knowledge centers (notably the Faculty of Mechanical Engineering), therefore invests in recent years in joint research of fiber lasers, trying to compete with large corporations and in the long term to maintain and improve its market position . Research has focused primarily in complex laser systems operating in the range of short and ultra-short laser pulses, as well as other innovative, cost-effective concepts of fiber lasers, directed towards the final applications in industry and medicine.   The project goal is to design and manufacture of a test pulsed fiber laser with output pulses in the range of 20-90 ns and the operating frequency from 10 kHz to about 300 kHz, average output power of about 10W and a polarized output so that it is suitable for frequency doubling. In order to achieve best possible robustness, compactness and cost effectiveness of the system it will be based on gain switching and a new type of optically active fiber will be used that leads only one polarization (as opposed to fiber-type "PM", which merely maintain polarization). In this case, the resonator itself does not require any additional optical element; therefore, the design of the system in terms of optical components is very simple. Required optical fibers will be developed and manufactured by international project partner NKT Photonics from Denmark, leading in this area in the world. Their participation in the project will also be important from technological point of wiev regarding the fiber preparation for use in laser resonators (preparing of end facets, cleaving, splicing,...). In order to achieve short laser pulses by the mentioned range an adequate pumping system will be developed and produced in the project, in cooperation with »Institute for Production Engineering and Laser Technology« from Vienna University of Technology, Austria. It will use multiple single emitter laser diodes coupled into a standard 125/105 multimode fiber, which will then be joined using a "beam combiner". Latest types of laser diodes will be selected, allowing fast driving of high peak power, without notably reducing the lifetime. An appropriate electronic controller will also be developed, which, together with precise temperature control will ensure the required output parameters of the pumping system (switching speed, the center of the spectrum and even the full width of the spectrum to some extent).
Significance for science
In the framework of the project a numerical model based on rate equations was designed and developed. With the help of the model it is possible to predict the impact of peak power and duration of the pumping pulse on the laser output so it was possible to successfully optimize the experimental layout. The model and its results were published in the paper [1], where the description of such time and local dependencies is done by time integration only. Great flexibility of the numerical model which was demonstrated also in the description of pulsed operation achieved by gain switching as well as Q switching has been tested in the case of time multiplexed two-channel Q switched laser [2]. The significance of the numerical model for the development of science is also reflected in the fact that it enabled a deeper understanding of dynamic processes in fiber lasers, which have led to the following significant results, which are also important for the development of science. We were able to demonstrate that it is possible with fiber lasers doped with active ions Yb to achieve pulses in the range of less than 50 ns duration, which is interesting for industrial and medical applications. Record values have been achieved in terms of the short duration of the output pulses, namely 28 ns with peak power of 1.4kW [3] while with further upgrading by absorption of the excess pumping light even 2.3 kW [4]. In-depth theoretical and experimental analysis was also carried out regarding the influence of the wavelength of the output pulse [5]. An important result for the development of science is certainly a successful demonstration of a Q switched laser system based on ytterbium micro-structured rod-like active fibers, which enables a strong delocalisation of higher modes in the core. Maximum peak power of laser pulses in this case was 4.4 kW and represents a record value for a single-stage ytterbium Q switched [6] [7]. References: 1. V. Agrež and R. Petkovšek, "Gain-switched Yb-doped fiber laser for microprocessing," Appl. Opt. 52, 3066-3072 (2013). 2. V. Agrež, F. Bammer, B. Podobnik, and R. Petkovšek, "Influence of the retardation of the multiplexing element in a dual channel Q-switched laser," Applied Physics B 112, 73-81 (2013). 3. R. Petkovšek and V. Agrež, "Single stage Yb-doped fiber laser based on gain switching with short pulse duration," Opt. Express 22, 1366-1371 (2014). 4. J. Petelin, V. Agrež, B. Podobnik, and R. Petkovšek, "Short pulsed gain-switched fiber laser with improved efficiency utilizing unabsorbed pump recovery," Opt. Express 22, 20588-20594 (2014). 5. V. Agrež and R. Petkovšek, "Gain switch laser based on micro-structured Yb-doped active fiber," Opt. Express 22, 5558-5563 (2014). 6. R. Petkovšek, V. Agrež, D. Sangla, J. Saby, R. B. Picard, and F. Salin, "Gain-switched ytterbium-doped rod-type fiber laser," Laser Phys. Lett. 11, 105808 (2014). 7. V. Agrež, R. Petkovšek, D. Sangla, J. Saby, R. B. Picard, and F. Salin, "Effect of repetition rate on gain-switched fiber laser output pulses," Laser Phys. 24, 105108 (2014).
Significance for the country
In the course of the project a great amount of new knowledge and technologies in the field of fiber lasers was won, which are important for the development of Slovenia and especially fot the Slovenian manufacturers of laser systems for medicine and industry (Fotona, Optotek and LPKF). The key skills that are important for further development are associated with in-depth knowledge of the dynamic processes in fiber lasers. Equally important are the new innovative approaches regarding laser pumping systems, which may be of wider use not only for fiber lasers in but also for other types, for example solid-state lasers. Also important is the experience the researchers have accumulated in the design of fully integrated fiber lasers (ie. all fiber laser). Mastering the technology of fiber laser systems for use in industry and medicine is crucial for the further development of Slovenian high-tech companies operating in the field of laser systems. Fiber lasers are in many areas already replacing existing laser laser systems (especially solid-state lasers), so it is important for Slovenian companies to master this new technology and thus potentially improve their position in the market. The results of the project provide a good basis for more in-depth long-term cooperation both between the companies, as well as with the researchers from the Faculty of Mechanical Engineering, University of Ljubljana. In the future the competence of the research group is greatly improved and thus the chances of winning further research projects in industry and funding from the European program "Horizon 2020".
Most important scientific results Annual report 2011, 2012, 2013, final report, complete report on dLib.si
Most important socioeconomically and culturally relevant results Annual report 2011, 2012, 2013, final report, complete report on dLib.si
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