title: Micromachined optical fiber current sensor.
abstract: We describe a micromachined optical fiber current sensor. The sensing element consists of a squared silicon membrane (8 mm long and 20 microm thick) that has a cylindrical permanent magnet (NdFeB alloy, 3-mm diameter, 1.5 mm high) fixed on its central region. This structure allows the permanent magnet to vibrate in the presence of the magnetic field gradient generated by an ac. A linear relation between the electrical current and the magnet displacement was measured with white-light interferometry with an optical fiber low-finesse Fabry-Perot microcavity. A measurement range of 0-70 A and a minimum detectable intensity of 20 mA were obtained when distance D between the membrane and the electrical power line was 5 mm. The output signal directly shows a linear response with distance D.
authors.affiliation: Laboratorio de Instrumentacin Espacial, División de Ciencias del Espacio, Instituto Nacional de Técnica Aeroespacial ~INTA!, 28850 Torrejón de Ardoz, Madrid, Spain. lopezhr@inta.es
authors.forename: R L
authors.initials: RL
authors.lastname: Heredero
authors.forename: R
authors.initials: R
authors.lastname: Fernández de Caleya
authors.forename: H
authors.initials: H
authors.lastname: Guerrero
authors.forename: P
authors.initials: P
authors.lastname: Los Santos
authors.forename: M
authors.initials: M
authors.lastname: Cruz Acero
authors.forename: J
authors.initials: J
authors.lastname: Esteve