© 1999 Optical Society of AmericaLópez Heredero, R.Fernández de Caleya, R. F.Guerrero, H.Los Santos, P.Cruz Acero, M.Esteve, J.2021-09-272021-09-271999-09-01Applied Optics 38(25): 5298-5305(1999)1559-128Xhttps://opg.optica.org/ao/abstract.cfm?uri=ao-38-25-5298http://hdl.handle.net/20.500.12666/469We describe a micromachined optical fiber current sensor. The sensing element consists of a squared silicon membrane (8 mm long and 20 µm 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.engOptical FibersPressure Sensorsinfo:eu-repo/semantics/article10.1364/AO.38.0052982155-3165info:eu-repo/semantics/restrictedAccess