Optical fiber sensor with distributed parameters based on optical fiber reflectometry

The paper concerns the optical fiber sensors with distributed parameters based on the combination of the polarization optical time domain reflectometry (PO-OTDR) and the photon counting OTDR (PC-OTDR) using standard optical fibers (OF). In the first part a simple introduction into the optical fiber sensors and measurement of the pressure, strain, and torsion is brought. Further the principles of PC-OTDR and PO-OTDR and their application to the realization of optical fiber sensors are briefly explained. The sensor model built on the cascade model of OF is also described. The main part of the paper is a detailed numerical model of OF sensor for the strain distribution measurement. Finally the results of the measured data by the PO-OTDR are analyzed