Multiplexed Extrinsic Fiber Fabry–Perot Interferometric Sensors: Resolution Limits

Abstract

Resolution investigation of multiplexed displacement sensors based on\nextrinsic fiber Fabry-Perot interferometers (EFPI) was carried out. The cases\nof serial and parallel configurations were considered, the analysis of the\nproblems and the advantages of the both was performed. An analytical model,\ndescribing the resolution limits for the both configurations was developed.\nSerial and parallel multiplexing schemes have been experimentally implemented\nwith 3 and 4 sensing elements, respectively. For the both configurations the\nachieved optical path difference (OPD) standard deviations were between 30 and\n80 pm, which is, to the best of our knowledge, more than an order better than\nany other multiplexed EFPI resolution ever reported. A good correspondence\nbetween experimental results and analytical predictions was demonstrated. A\nmathematical apparatus, relating the attained sensors resolutions with the\nnumber of multiplexed sensors and the optical setup parameters was developed,\nalso demonstrating good correspondence with the experimental results. The main\norigins of possible sensors cross-talk are described, with the supporting\nexperiments, proving an importance of its consideration. Some recommendations,\nbased on the theoretical analysis and experimental studies, dedicated to\noptimization of sensors resolution and elimination of the cross-talk influence\nare provided.\n