Derivative Fiber-Optic Sensors Based On Phase-Nulling Optical Gyro Development

<title>Fiber optic smart structure system for natural structures</title>

“…While many types of fiber sensors have very long gauge lengths [2][3][4] the Sagnac interferometer based strain sensor has the potential to meet all the criteria for a successful system [51. Early demonstrations [6] showed that displacements on the order of 100 microns could be measured over a distance of 150 meters using bulk optic components operating at 0.8 microns. By using modern components operating at 1.3 microns the system could be extended to 10 km or more with similar sensitivity.…”

Fiber-Optic Sensor Systems For Aerospace Applications

“…Issues that are important include (2) the type of coating used on the fiber and its compatibility with the material into which it is to be embedded, (2) getting the fibers into and out of the panels used to construct the vehicle, (3) appropriate orientation of the fiber in the material to avoid structural degradation and (4) the wide range of materials of interest seen from the relatively low temperature and pressure processing of the graphite epoxy materials to the very high temperatures and pressures associated with titanium and carboncarbon.…”

“…This is particularly critical for aerospace applications where weight is a major issue and the usage of electronic sensors with sufficient redundancy adds so much weight that it is cost prohibitive for many applications. Fiber sensors have several other important advantages when compared to electrical technology including (1) immunity to electromagnetic interference eliminating shielding and ground loop problems, (2) electrical isolation and the elimination of conductive paths which is of particular importance to composites and the problem of lightning strickes, (3) fiber sensors are compatible with being embedded in structures during the manufacturing process at temperatures and pressures that are far beyond the limits of current electronic technology, and (4) the data carrying bandwidth of fiber optics is so high that hundreds and potentially thousands of sensors can be supported by a single fiber.…”

“…(1) monitoring the manufacturing process and performance of nondestructive evaluation, (2) health monitoring systems that check the condition of the structure for strains, torque, compression, cracks, impacts and leakage, and (3) the measurement of environmental parameters around the platform during flight such as temperature, pressure, shock location, radiation, electric and magnetic fields.…”

“…The first issue is the successful placement of fibers into composite or metallic materials in a manner compatible v\n th their sensing functions. Issues that are important include (2) the type of coating used on the fiber and its compatibility with the material into which it is to be embedded, (2) getting the fibers into and out of the panels used to construct the vehicle, (3) appropriate orientation of the fiber in the material to avoid structural degradation and (4) the wide range of materials of interest seen from the relatively low temperature and pressure processing of the graphite epoxy materials to the very high temperatures and pressures associated with titanium and carboncarbon. Once the fibers have been appropriately embedded, fiber sensors must be selected based on performance criteria established by the system designer.…”