Project Title:

Grating-Based Fiber-Optic Sensor Arrays for Smart Aerospace Materials

  94-1	04.03	4107

  Grating-Based Fiber-Optic Sensor Arrays for Smart Aerospace 
  Materials

Abstract:

Intelligent Fiber Optic Systems proposes a new approach for 
including sensing and processing functions in aerospace 
materials. This integrated structure exploits novel combination 
of compatible and complementary known techniques: (a) Lattice 
Sensor arrays (LSAs), (b) Two-Mode Fibers (TMFs), (c) Two-Mode 
Couplers TMCs, (d) Fiber Bragg Gratings (FBGs), (e) Active 
(piezo-electric, electro- or magnetostrictive) Materials (AMs). 
LSAs provide efficient sensing interconnection networks with an 
input bus for distributing optical energy to sensors and output 
bus for collecting sensed signals. Using TMFs means these buses 
are modally separate but in a single fiber. TMCs allow modal 
multiplexing. FBGs perform sensing and modal cross-coupling 
functions. In general, measurands disturb FBGs, thereby shifting 
their Bragg wavelengths measured by a demodulation subsystem. A 
TMF/TMC/FBGbased LSA is itself electromagnetic interference-
immune and adds intelligent health monitoring functions to 
passive aerospace structures. Localized transducer sensitivity 
(temperature, electromagnetic field, voltage, etc.) and enhanced 
intelligence is given by coating or embedding the FBGs in 
"active" materials. In Phase I, a single-sensor prototype will 
be constructed and evaluated for sensitivity, dynamic range, 
linearity, reliability and installation options.

As well as smart aerospace material applications (for space 
station, spacecraft and aircraft applications), real-time space, 
lunar and planetary environmental monitoring systems, and 
intelligent buildings in lunar and other hostile environments, 
significant potential for commercial spinoffs exists in 
intelligent transport sytems, roads, bridges, automobile and 
submarine manufacturing. The proposed sensing networks offer 
higher sensitivity and reliability than those of conventional 
approaches and can be mass produced. These features make the 
proposed smart sensors marketable and can attract follow-on non-
federal and private sector funding.

Key Words

Intelligent Fiber Optic Systems
1778 Fordham Way
Mountain View, CA 94040