1. Department of Information Engineering, University of Padova, Padova, Italy
2. IMEM, CNR Parma, Parma, Italy
3. LIGENTEC SA, EPFL Innovation Park Bâtiment L, Ecublens, Switzerland
4. Photonics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg, Sweden
5. Photonics Research Group, Ghent University-imec, Gent, Belgium