Quasi-distributed single-length polarimetric sensor

A quasi-distributed polarimetric sensor employing a single length of polarization-preserving fiber is described. The sensing segments are identified by miniature rings that squeeze the fiber to couple power from one optical mode to the orthogonal mode while avoiding any mechanical damage to the fiber. A superluminescent-diode source allows us to exploit the coherent-multiplexing concept, which yields high resolution and high precision. Experimental results confirm this approach and point toward the development of a quasi-distributed sensor with polarimetric sensitivity, high spatial resolution, and fiber-optic mechanical integrity.