15 September 1995 Multiplexed extrinsic Fabry-Perot interferometers and applications
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Proceedings Volume 2507, Distributed and Multiplexed Fiber Optic Sensors V; (1995) https://doi.org/10.1117/12.219615
Event: European Symposium on Optics for Environmental and Public Safety, 1995, Munich, Germany
Abstract
Extrinsic Fabry-Perot interferometric (EFPI) sensors have previously been demonstrated for relative strain and temperature measurements for smart structure applications. Inherent difficulties in the signal processing of these devices has created the need for absolute measurement capabilities. In this paper, we present an absolute measurement technique based upon white-light interferometric path matching. The system matches a reference gap to the sensing gap of an EFPI. When the difference of these two lengths is within the coherence length of the source, an intensity envelope is created in the system output. Determination of the corresponding path mismatch indicates the size of the sensor gap and hence strain can be determined. This measurement technique is capable of multiplexing an array of EFPI sensors and data will be presented demonstrating four multiplexed devices. Theoretical considerations for system optimization are also presented. As the only fiber-optic sensors subcontractor to Northrop Corporation on the Navy/Air Force-sponsored Smart Metallic Structures (SMS) program, Fiber & Sensor Technologies (F&S) is developing the optical fiber fatigue gage instrumentation for a multiplexed, in situ structural health monitoring system for aging aircraft. In March, 1995, F&S successfully demonstrated the system on a full-size F/A-18 wing-box spar fully instrumented with 12 of F&S' patented EFPI optical fiber strain gages. F&S is now in process of up-scaling the signal processing system in addition to the optics and intends to demonstrate a second generation multipoint sensor system capable of simultaneously monitoring strains at up to 60 different sites throughout the aircraft later in 1995 or early 1996.
© (1995) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Kent A. Murphy, Vikram Bhatia, Richard O. Claus, Paul Grems Duncan, Mark E. Jones, Jennifer L. Grace, Jonathan A. Greene, Tuan A. Tran, "Multiplexed extrinsic Fabry-Perot interferometers and applications", Proc. SPIE 2507, Distributed and Multiplexed Fiber Optic Sensors V, (15 September 1995); doi: 10.1117/12.219615; https://doi.org/10.1117/12.219615
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