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 m thick͒ that has a cylindrical permanent magnet ͑NdFeB alloy, 3-mm diameter, 1.5 mm high͒ 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.

Fiber bragg grating current sensor based on birefringence effect

“…Several physical principles and effects can be used as the basis of the fiber optic current sensors, such as the electromagnetic induction effect, the Faraday rotation effect, the magnetostrictive effect, the heat effect, the converse piezoelectric effect, the electromagnetic force effect, and so on [1–4]. A traditional Rogowski coil is often used to sample the transmission‐line current in those fiber optic current sensors based on the electromagnetic induction effect.…”

“…There are two kinds of electromagnetic force‐based fiber current sensors. One is to change the cavity length of the F‐P interferometer due to the electromagnetic force‐generated displacement [3], and the other is to change reflected wavelength of the FBG sensor due to the electromagnetic force‐generated deformation [4].…”

A 2kV ESD-Protected 18GHz LNA with 4dB NF in 0.13μm CMOS

“…Several physical principles and effects can be used as the basis of the fiber optic current sensors, such as the electromagnetic induction effect, the Faraday rotation effect, the magnetostrictive effect, the heat effect, the converse piezoelectric effect, the electromagnetic force effect, and so on [1][2][3][4]. A traditional Rogowski coil is often used to sample the transmission-line current in those fiber optic current sensors based on the electromagnetic induction effect.…”

A study of the optical properties of photopolymer Fabry-Perot microcavities by a dual-wavelength fibre optic architecture

“…In this case, it is necessary to have a compensating receiving interferometer in order to recover the phase changes induced by the measurand. This technique, designated white light interferometry (WLI), has been extensively used to interrogate LFFPI projected for the measurement of several physical parameters, such as static and dynamic strains [8], pressure and temperature [9], electric field [10] and electrical current [11]. However, there are situations where the cavity length is smaller than the coherence length of the light source.…”