1. The Department of Fiber Photonics Leibniz Institute of Photonic Technologies (IPHT) Albert-Einstein-Street 9 07745 Jena Germany
2. Research & Development Specialty Fiber Optics Heraeus Quarzglas GmbH & Co. KG Quarzstreet 8 63450 Hanau Germany
3. Institute for Photonics & Advanced Sensing (IPAS) School of Physical Sciences University of Adelaide Adelaide SA 5005 Australia
4. Abbe Center of Photonics and Faculty of Physics Friedrich-Schiller-University Jena Max-Wien-Platz 1 07743 Jena Germany
5. Otto Schott Institute of Materials Research (OSIM) Friedrich Schiller University Jena Fraunhoferstr. 6 07743 Jena Germany