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

Reviews on Corrugated Diaphragms in Miniature Fiber-Optic Pressure Sensors

Corrugated diaphragms (CDs) have been widely used in many fields because of their higher pressure sensitivity and wider linear range compared to flat diaphragms (FDs) in the same circumstances. Especially in the application of miniature fiber-optic pressure sensors, the introduction of the corrugated structure gives the sensor high sensitivity, large dynamic range, good linearity, small hysteresis, good stability, and so on. Research on CD-based miniature fiber-optic pressure sensors has gradually attracted more attention in recent years. In this paper, the principles of operation of a miniature fiber-optic pressure sensor are briefly introduced, then the mechanical properties of FD and CD, as well as their influences on the performance of the sensor, are analyzed in detail. The application status of CDs in miniature fiber-optic pressure sensors is reviewed, and our conclusions and the prospects for the application of CDs in miniature fiber-optic pressure sensors are given finally.

Polarimetric fiber laser sensor for hydrostatic pressure

A polarimetric Fabry-Perot fiber laser sensor for fluid pressure up to 100 MPa is investigated. The fluid acts on one of two elliptical-core fiber sections in the laser cavity, producing a shift in the differential phase of the two orthogonal polarization modes and thus a variation in the beat frequencies of the corresponding longitudinal laser modes. The second fiber section, with a 90 degrees offset in the core orientation, compensates for temperature-induced phase shifts. The dispersion in the birefringent fiber Bragg grating reflectors is employed to remove the near degeneracy of the polarization mode beat frequencies of a given order and to improve substantially the resolution of the sensor to a few parts in 10(6) of the free spectral range. Further investigations address the effect of the fluid on the integrity of the fiber, the influence of various fiber coatings on the sensor response, and the intrinsic stability of erbium-doped and undoped sensing fibers under fluid pressure.