Ultra-high-sensitivity two-dimensional bend sensor

Abstract

A multicore fibre Fabry-Perot-based strain sensor interrogated with tandem interferometry for bend measurement is described. Curvature in two dimensions is obtained by measuring the difference in strain between three co-located low finesse Fabry-Perot interferometers formed in each core of the fibre by pairs of Bragg gratings. This sensor provides a responsivity enhancement of up to 30 times that of a previously reported fibre Bragg grating based sensor. Strain resolutions of 0.6 n epsilon/Hz(1/2) above 1 Hz are demonstrated, which corresponds to a curvature resolution of similar to 0.012 km(-1)/Hz(1/2)

Multipoint Two-Dimensional Curvature Optical Fiber Sensor Based on a Nontwisted Homogeneous Four-Core Fiber

“…Non-twisted four-core MCFs have been also proposed to implement curvature sensors [12][13]. Using this type of fiber and with the aim of achieving the best curvature resolution an interferometric interrogation scheme has been proposed in combination of Fabry-Pérot cavities and FBGs [14,15].…”

Conjugate Left- and Right-handed Material Bilayered Substrates Qualify the Subwavelength Cavity Resonator Microstrip Antennas as Sensors

“…In recent years, there have been continued research and development of electromagnetic field sensors either for military use or commercial application [27][28][29][30][31]. Such sensors are mostly based on electrically small antennas which need well responses to the targets, but minimal ones to the unwanted fields.…”

Pico-strain measurement using optimised fibre Fabry-Perot sensor system with reference wavelength

“…Described as a tandem interferometer (TI) arrangement illuminated with a narrowband fiber amplified spontaneous emission (ASE) source, the theoretical noise-limited resolution of a fibre F-P (FFP) sensor system has been conducted by Shi et al [1]. Interferometric interrogation has demonstrated experimental phase resolution of about 270 dB above 1 Hz in a bend sensor [2] and at 500 Hz in vibration measurement [3]. All these investigations are based on the assumption that the two FBGs have identical spectra.…”

“…Although the calibration signal generated in an interrogation interferometer can be reduced by more than 40 dB [2], from a statistical signal processing point of view, the noise level of the differential result in other frequency bands will be increased by about 3 dB by the subtraction operation of two uncorrelated noises with the same intensity.…”

“…A fibre laser, with a wavelength l F ¼ 1548.07 nm, serves as a reference source to illuminate the MI and is collected by PD1. The differential result is given by [2] …”