1. Department of Fiber Optical Sensor Systems, Fraunhofer Heinrich Hertz Institute, Goslar, Germany
2. Institute for Energy Research and Physical Technologies and the Energy Research Center of Lower Saxony (EFZN), Clausthal University of Technology, Goslar, Germany
3. Energy Research Center of Lower Saxony (EFZN), Clausthal University of Technology, Goslar, Germany
4. Miopas GmbH, , Goslar, Germany
5. Department Fiber Optical Sensor Systems, Fraunhofer Heinrich Hertz Institute, and the Institute for Energy Research and Physical Technologies and the Energy Research Center of Lower Saxony (EFZN), Clausthal University of Technology, Goslar, Germany