1. Department of Telecommunications and Teleinformatics, Wroclaw University of Science and Technology, Wrocław, Poland
2. LISA Laser Products GmbH, Katlenburg-Lindau, Germany
3. Mid-Infrared Photonics Group, George Green Institute for Electromagnetics Research, Faculty of Engineering, University of Nottingham, Nottingham, U.K.
4. Faculty of Electronics and Information Technology, Institute of Electronic Systems, Warsaw University of Technology, Warsaw, Poland