Partially multiplexing sensor network exploiting low coherence interferometry

Fiber-optic-based absolute displacement sensors at 1500 nm by means of a variant of channeled spectrum signal recovery

An absolute displacement-sensing system based on channeled spectrum processing capable of simultaneous interrogation of fiber Bragg gratings and fiber-optic interferometric sensors is presented in which the role of the optical spectrometer is performed by a scanning Fabry-Perot filter. We demonstrate a resolution of +/-50 nm with an estimated dynamic range of 1 part in 10(5).

Quasi-distributed fiber-optic strain sensor: principle and experiment

Sensors capable of making distributed measurements allow for monitoring of the entire structure. Optical fiber sensors are especially attractive for this purpose, since they are geometrically versatile and can be readily integrated within various types of structure and material. Development and characteristics of a quasi-distributed intrinsic fiber-optic strain sensor based on white-light interferometry are described. The research presented here describes the development of a new optical fiber sensor system for measurement of structural strains based on double white-light interferometry. Individual segments of single-mode optical fibers forming a common-path interferometer are linked in series, and a scanning white-light interferometer provides for distributed sensing of strain signals from various locations in the structure. The system is configured for automatic compensation of drift due to environmental effects, i.e., temperature and vibration. Strain gauges were employed for comparison and verification of strain signals as measured by the new system. The experimental results demonstrate the linearity of the system and the capability for distributed sensing of strains.

Prototype fiber-optic-based pressure probe with built-in temperature compensation with signal recovery by coherence reading

A prototype multimode fiber-based Fabry-Perot interferometric pressure probe utilizing a corrugated diaphragm with built-in temperature compensation, with signal recovery by coherence reading, has been constructed and demonstrated. A separate fiber-optic-based temperature sensor was incorporated into the pressure sensor to permit the pressure measurement to be corrected for the temperature dependence of the pressure probe. A measurement range to resolution of 3.6 × 10(4) - 1 and an overall measurement accuracy of ±0.15% have been achieved. This system represents a practical approach for industrial use.