Low-coherence Michelson interferometric fiber-optic multiplexed strain sensor array: a minimum configuration

Abstract

A minimum configuration Michelson fiber-optic low-coherence interferometric quasi-distributed sensing system is proposed that permits absolute length measurement in remote reflective sensor arrays. The sensor's reflective signal characteristics have been analyzed, and the relationship between intensities of light and number of sensors is given for evaluation of multiplexing potential. The proposed sensing scheme will be useful for the measurement of strain distribution. An important application may be strain monitoring in smart structures. Experimentally, four-sensor array has been demonstrated.

Development and laboratory validation of in-line multiplexed low-coherence interferometric sensors

“…Among all the systems proposed in the literature, particularly promising for future deployment seems to be the work by Yuan et al [16][17][18]. If we restrict our attention to interferometric sensors that are commercially available and suitable for integration into civil structures, the SOFO (Surveillance d'Ouvrages par Fibres Optiques) system, developed and commercialized by Smartec SA [19], is possibly the best known representative of this family.…”

A fibre-optic low-coherence quasi-distributed strain sensing system with multi-configurations

“…It should be mentioned that, although the measurement results (interferogram peaks shift) for the linear array or loop array sensors are polarization independent (in the strict sense, the effect of polarization is neglected in that case), the measurement results in the case of an interference fringe lowered nearly to the floor noise are under the influence of the polarization states. The polarization issues in the lowcoherence fibre optic Michelson interferometric quasidistributed strain sensor array by considering the effects of a localized region of birefringence-induced polarization states in the sensing fibre gauge length are analysed in [12,13]. It is shown that the amplitude of the interferogram peak would fade due to the localized region strain induced birefringence in each fibre sensor (fibre segment).…”

Large-Dynamic-Range and High-Stability Phase Demodulation Technology for Fiber-Optic Michelson Interferometric Sensors

“…Fiber-optic Michelson interferometric sensors have been widely researched for monitoring vibration, soundwave, acceleration, liquid refractive index, magnetic field, flow velocity and strain because of their advantages such as high sensitivity, light weight, electromagnetic immunity and capability of multiplexing [ 1 , 2 , 3 , 4 , 5 , 6 ]. Several demodulation technologies have been put forward to interrogate the phase signal of fiber-optic Michelson interferometric sensors, including phase generate carrier (PGC) demodulation [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ], 3 × 3 coupler demodulation [ 15 , 16 , 17 , 18 ] and spectrum demodulation [ 19 , 20 ].…”