Optical shape sensing system, medical apparatus and method for optical shape sensing

Abstract

The present invention relates to an optical shape sensing system for sensing a shape of a medical device (), comprising an input polarization controller () for setting an input polarization state of an input light signal, at least one interferometer unit () for dividing said polarized input light signal into a device signal and a reference signal, guiding said device signal to be scattered within an optical fiber () inserted into said device () and coupling said scattered device signal with said reference signal to form an output light signal, and at least one measurement branch () comprising an output polarization controller arrangement () for setting an output polarization state of said output light signal, a polarizing beam splitter () for splitting said polarized output light signal into two signal portions, each being in a corresponding one of two signal portion polarization states, and a detector arrangement () comprising two detectors (), each for detecting a corresponding one of said two signal portions, wherein said input polarization controller () is configured to set two pairs of input polarization states, or said output polarization controller arrangement () is configured to set two output polarization states each for enabling a corresponding one of two pairs of signal portion polarization states, wherein each pair of input or signal portion polarization states are representable by a corresponding one of two axes in a Poincaré sphere different from each other.