Pressure Sensor Catheter based on piezoelectric actuated Aluminum Nitride Membrane and Fiber Tip Fabry-Perot-Interferometer

Fiber-optic sensors are particularly predestined for applications in medical measurement catheters. We introduce a pressure sensor catheter consisting of an extrinsic Fiber-optic Faby-Pérot-Interferometer realized between the tip of an optical fiber and a reflective multilayer membrane of a pressure sensor chip. The membrane can be actuated by piezoelectric aluminum nitride. A Fiber Bragg Grating interrogation device is used to analyse the optical signals. First, the mechanical structure of the sensing components, both coated with a 5 mm diameter mantle is described. Then, experimental investigations in wavelength shift due to hydrostatic pressure are presented. The pressure sensitivity under passive conditions is characterized and an active working principle between pressure impact and regulating voltage is demonstrated. Furthermore, the temperature dependence of the probe is quantified. Out of these main points the working principle of a piezoelectric actuated pressure sensor for invasive medical catheter interventions was confirmed.