How are extrinsic fiber optic sensors used?

Extrinsic fiber optic sensors give best protection of measurement signals against noise corruption. Unluckily, several conventional sensors produce electrical output that must be converted within an optical signal for utilise along with fiber. For instance, in the case of a platinum resistance thermometer, the temperature changes are translated within resistance changes. The PRT should therefore have an electrical power supply. The modulated voltage level at the output of the PRT can in that case be injected in the optical fiber through the usual type of transmitter. It complicates the measurement process and implies that low voltage power cables should be routed to the transducer.

Extrinsic sensors are utilized to measure torque, rotation, vibration, displacement, velocity, acceleration and twisting.