Distributed pressure sensor with a mode-locked fiber-ring laser

We propose and demonstrate a novel distributed fiber-laser pressure sensor. A transverse pressure position is located by determination of the free-spectral range shift induced by mode coupling in an intracavity polarization-maintaining fiber. We demonstrate that the stability and the spatial resolution of the sensor can be enhanced drastically by introduction of a novel mode-locking technique. Resolution of 54 cm in the 150-m range can be realized.