Polarization-induced fading in fiber-optic sensor arrays

The statistics of polarization-induced visibility fading is studied for fiber-optic interferometric (Michelson or Mach-Zehnder) sensor arrays made of either regular single-mode fibers or polarization-maintaining fibers. Performance is measured in terms of the probability to observe visibilities, all of which exceed a given value, for all members of the array. Very poor performance is obtained for arrays made of nonpolarization maintaining fibers, unless the input state of polarization is dynamically controlled to optimize the visibility of the worst sensor of the array. While the use of the more costly polarization-maintaining fibers could, in principle, solve this polarization-related fading problem, finite extinction ratios of couplers and splices make the performance of such arrays comparable to that of nonpolarization maintaining arrays with optimally controlled input-polarization.