Elsevier

Results in Physics

Volume 18, September 2020, 103286
Results in Physics

A broadband Faraday fiber-optic current sensor with excess noise compensation

https://doi.org/10.1016/j.rinp.2020.103286Get rights and content
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Highlights

  • Excess noise is the major noise component of the proposed fiber-optic current sensor.

  • Excess noise suppression enhances the signal-to-noise ratio of the current sensor.

  • Bending birefringence in the spun fiber wound to a coil limits the noise suppression.

  • A special winding of the small-radius sensing coil enables efficient noise suppression.

Abstract

A Faraday fiber-optic current sensor with suppression of excess noise produced by a low-coherent light source is presented. The sensor is designed to detect short current pulses and represents an in-line interferometer with a sensing element based on a spun highly birefringent fiber. To suppress the excess noise, a two-channel light detection scheme without an additional delay line is applied. It is established that bending birefringence induced in the spun fiber wound on a coil limits the noise suppression. To minimize this effect, a new geometry of the sensing coil is used. The proposed sensor exhibits a 5-fold improvement of the signal-to-noise ratio and the same enhancement of the sensitivity to a value of 0.8A in the 3.5 MHz bandwidth. The minimum duration of the measured current pulse is 200 ns.

Keywords

Faraday effect
Fiber-optic current sensor
Excess noise

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