  Resolution investigation of multiplexed displacement sensors based on
extrinsic fiber Fabry-Perot interferometers (EFPI) was carried out. The cases
of serial and parallel configurations were considered, the analysis of the
problems and the advantages of the both was performed. An analytical model,
describing the resolution limits for the both configurations was developed.
Serial and parallel multiplexing schemes have been experimentally implemented
with 3 and 4 sensing elements, respectively. For the both configurations the
achieved optical path difference (OPD) standard deviations were between 30 and
80 pm, which is, to the best of our knowledge, more than an order better than
any other multiplexed EFPI resolution ever reported. A good correspondence
between experimental results and analytical predictions was demonstrated. A
mathematical apparatus, relating the attained sensors resolutions with the
number of multiplexed sensors and the optical setup parameters was developed,
also demonstrating good correspondence with the experimental results. The main
origins of possible sensors cross-talk are described, with the supporting
experiments, proving an importance of its consideration. Some recommendations,
based on the theoretical analysis and experimental studies, dedicated to
optimization of sensors resolution and elimination of the cross-talk influence
are provided.
