Future advanced fixed- and rotary-wing aircraft, launch vehicles, and spacecraft will incorporate fiber-optic smart sensor networks to monitor structural integrity and manage overall structural health. This paper describes the design of an acoustic emission (AE)-based micromachined sensor for new and aging aircraft applications to assess preflight readiness, in- flight structural integrity, and post-flight time-based maintenance. This unique sensor approach combines silicon micromachining, free-space optical waveguides, high-speed optical interconnects, and supervisory sensor management to measure stress waves related to AE events. A unique second-generation polysilicon resonant microbeam sensor design is described. It incorporates a micron-level vacuum-encapsulated microbeam to optically sense structural-integrity acoustic parameters and to optically excite the sensor pickoff. Its principal of operation, significant payoffs and benefits, and wafer-level laboratory test data results are summarized.
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