Co-funded by the German Federal Ministry of Education and Research (BMBF)
Duration: March 2015 – February 2018
The passive three-dimensional profile and shape measurement of mechanical objects by means of fiber optic sensor technology is a current international hot topic, as it allows, in particular in the field of medical technology completely new possibilities for navigation and positioning of various medical instruments. In particular, flexible instruments applied in endoscopy or angiography could benefit from such a shape sensing technology significantly.
Because the technique works exclusively fiber optical, it is independent from electro-magnetic interferences and can be applied in operating and screening rooms within the human body. Instruments, which are equipped with such a navigation principle, would not only easier to handle, but also would open up new application areas that would be unthinkable without knowledge of the location-positioning.
The Fraunhofer Heinrich Hertz Institute has developed on the basis of the femtosecond laser technique, a method for directly inscribing of waveguides and periodic modulation of the refractive index in both the core and in the cladding of an optical fiber. This allows a variety of microscopic optical strain sensors in a fiber manufacture. An evaluation of the strain or compression measurement data gives the three-dimensional profile of the instrument in real time. Via adapted interfaces the determined information could be easily transferred in a three-dimensional presentation, which is provided to the treating physician for the navigation of the instrument.
With this method, it is now possible to use an inexpensive, ordinary standard single-mode fiber for three-dimensional profile measurement. The data transmission and the coupling of the readout light are exclusively realized via one single fiber core. This allows the usage of all known coupling and fiber elements from the telecommunication sector.