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Interferometric fiber optic accelerometers constitute a high-responsivity, high-resolution sensing architecture, with
achievable sensitivities of several rad/g and resolutions in the micro-g range, depending on the specific configuration.
Fiber Bragg grating (FBG) optical accelerometers offer ease of multiplexing but are inherently less sensitive than their
interferometric counterparts. Fiber-based accelerometers have the usual optical advantages of being lightweight,
electromagnetically immune, and non-spark emitting over traditional (piezo-electric) accelerometer architectures.
Among fiber optic sensing methodologies, both interferometric and FBG accelerometers can be interrogated using
phase-based demodulation, which offers advantages over intensity-based sensing schemes such as increased linearity,
repeatability, and insensitivity to extraneous measurands.
The performance of an accelerometer is often characterized in terms of its bandwidth, sensitivity, and resolution, all of
which depend on the specific transducer design (the mechanical architecture) as well as the optical interrogation
architecture. For a given optical interrogation architecture, a fundamental tradeoff exists in accelerometer transducer
design between bandwidth and sensitivity; attempts to increase bandwidth will generally result in a decrease in
sensitivity. This paper investigates the frequency and displacement characteristics that govern this tradeoff for several
transducer configurations, in order to determine a pair of configurations that offer the greatest sensitivity for a given
optical interrogation methodology (interferometric or FBG), at a prescribed bandwidth. The feasibility of several
mechanical architectures is assessed based on the physical dimensions required for a given configuration to achieve a
primary resonance of at least 15 kHz. The deflection of those configurations under their own self-weight is then
considered a measure of accelerometer sensitivity in the measurement band below primary resonance. This paper has
been reviewed by Los Alamos National Laboratory and received the following release number: LA-UR 10-00671.
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