Fig. 12: Ocean monitoring performed by exploiting the long sensing distance characteristic of optical fiber sensing.
From: Physics and applications of Raman distributed optical fiber sensing
a The state of polarization (SOP) at the receiver is monitored routinely (blue dots on the Poincaré sphere) while the input SOP stays stable (red star). For the Curie cable, the output SOP is robust, owing to relatively minimal perturbations along most of its path in the deep ocean (b). The robustness allows us to detect earthquakes or ocean waves that produce SOP anomalies by shaking or pressuring the cable (c). Because the three Stokes parameters are normalized to 1.0, only two are independent. In this study, we rotate the Stokes parameters to the north pole of the Poincaré sphere (9) and focus on analyzing the S1 and S2 parameters after rotation (d).
