TY - CONF A1 - Nöther, N. A1 - Krebber, Katerina A1 - Schneider-Glötzl, J. T1 - An all-digital implementation of the Brillouin optical frequency domain analysis for long-range distributed strain and temperature monitoring T2 - 8th International symposium on field measurements in geomechanics - FMGM 2011 (Proceedings) N2 - For long-range measurements in geotechnical and industrial applications, distributed optical fiber sensors have become a tool of increasing importance throughout the past decade. Classic deformation monitoring (performed by strain gauges etc.) and temperature monitoring (Pt100 and alike) deliver data from fixed, single spots of a structure; quasidistributed measurements (fiber bragg gratings) provide a Chain of discrete measurement points along a limited sensing length. In contrast, an opticai fiber connected to a device for distributed strain and temperature sensing (DTSS) will provide a continuous profile of strain and temperature - spatially resolved down to less than 1 m - over a ränge of several tens of kilometers. In DTSS measurements, the nonlinear opticai effect of stimulated Brillouin Scattering (SBS) is employed: two light waves with a stable, tunable frequency offset are injected into opposite ends of the sensing fiber, where they will form a beat pattem, at which parts of the light will be scattered. By matching the frequency offset of the light waves to the propagation of acoustic fluctuation in the opticai fiber, a power transfer from one light wave to the other can be measured; since the acoustic propagation directly shifts with train and temperature of the fiber, these two quantities can be measured by tuning the light waves’ frequency offset. T2 - 8th International symposium on field measurements in geomechanics - FMGM 2011 CY - Berlin, Germany DA - 12.09.2011 PY - 2011 SP - 1 EP - 6 AN - OPUS4-24664 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -