Figure: Experimental scheme
Probing the Ultimate Limit of Fiber-Optic Strain Sensing
Istituto Nationale di Ottica (CNR-INO), European Laboratory for Non-Linear Spectroscopy (LENS), & Menlo Systems
Authors: Gianluca Gagliardi (CNR-INO, LENS)
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The measurement of relative displacements and deformations is important in many fields such as structural engineering, aerospace, geophysics, and nanotechnology. Optical-fiber sensors have become key tools for strain measurements, with sensitivity limits ranging between 10−9 and 10−6 e (Hz)−1/2 (where e is the fractional length change). We report on strain measurements at the 10−13 e (Hz)−1/2 level using a fiber Bragg-grating resonator with a diode-laser source that is stabilized against a quartz-disciplined optical frequency comb, thus approaching detection limits set by thermodynamic phase fluctuations in the fiber. This scheme may provide a route to a new generation of strain sensors that is entirely based on fiber-optic systems, which are aimed at measuring fundamental physical quantities; for example, in gyroscopes, accelerometers, and gravity experiments.
G. Gagliardi, et al.: Probing the Ultimate Limit of Fiber-Optic Strain Sensing; Science 330, 1081 (2010); DOI: 10.1126/science.1195818