1. Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw, Poland
2. Institute of Optoelectronics, Military University of Technology, Gen. S. Kaliskiego 2, 00-908 Warsaw, Poland
3. Laser and Fiber Electronics Group, Faculty of Electronics, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
4. Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw, Poland