Abstract: A fiber-optic voltage sensor comprises at least one fiber-optic, piezoelectric sensor element (2a, 2b, 2c, 2d), which measures a predeterminable directional component of a local electric field. One or more than one piezoelectric sensor elements (2a, 2b, 2c, 2d) are arranged serially between two ends of the fiber-optic voltage sensor, each piezoelectric sensor element (2a, 2b, 2c, 2d) respectively measuring a directional component of a local electric field, which component lies parallel to a path element assigned to it, the path elements as a whole forming an open polygon connecting the two ends of the fiber-optic voltage sensor. Each sensor element (2a, 2b, 2c, 2d) has a gain which is proportional to a length of the path element assigned to it. In a preferred embodiment, the piezoelectric sensor elements (2a, 2b, 2c, 2d) are connected by spacers (3a, 3b, 3c).

Abstract: A measuring apparatus for space-resolved temperature measurement by optical backscattering measurement at optical waveguides, wherein an improvement in the signal-to-noise ratio is achieved by including an additional filter device to attenuate the Rayleigh peak in the backscattered light. The filter device preferably includes a polarizing beam splitter, behind which a quarter-wave plate and an interference filter are disposed in the transmission direction.