Abstract: The invention relates to a catheter system adapted for pressure sensing. It comprises a transmitter/receiver for polarized light and an optical fiber to be connected to said transmitter/receiver, said fiber at its distal end being provided with a cylindrical body of transparent plastic material, and said body having a hollow central inner lumen provided around its longitudinal axis, and said cylindrical body is provided with a mirror at its side facing away from said fiber.

Abstract: A catheter system including a catheter having a proximal end and a distal end and a device for determining the position of the distal end of the catheter relative to the position of the proximal end of the catheter, the device for determining the position including a glass fiber within a lumen of the catheter, the lumen being defined by a wall, a first polarization filter near the proximal end of the catheter, and a second polarization filter near the distal end of the catheter, wherein the first and second polarization filters are fixed with respect to the wall, and wherein the glass fiber is suitable for transporting polarized light while maintaining the direction of the polarization of the light substantially unchanged during torsional stress of the catheter.