Method and system for calibrating a conversion unit of a fiber optic sensor head

Electro-optic sensor system having a sensor head, said sensor head having an electro-optic conversion unit with scale factor calibration, the sensor head comprising

• in the conversion unit in the sensor head a conversion element and associated electrical conductors for creating electric or magnetic fields,
• an optical fibre being attached to the conversion element
• an electro-optical interrogation and read-out device;
• the conversion element being at least partly made from material(s) which causes the shape or physical dimensions of the element to change when subjected to said fields thus straining the fibre and providing a phase and/or intensity modulation of the an optical signal in the fiber, and
• the optical signal being detectable in read-out device
• characterized in that
• the sensing unit is adapted for generating electric signals and applying said signals to the electrical conductors of the conversion unit thereby producing said electric and magnetic fields,
• an electric supply unit is adapted for generating a chosen electric calibration signal and applying said calibration signal to the electric conductors of the conversion element thereby also producing said electric and magnetic fields,
• the interrogation and read-out device is adapted, e.g. with computer means to use the resulting received optical signals to calculate a calibration scale factor related with the conversion element.