Robust in-fiber spatial interferometer using multicore fiber for vibration detection

Abstract

We report the demonstration of a novel in-fiber spatially integrated Michelson interferometer based on weakly coupled multicore fiber (MCF) for vibration sensing. The compact interferometer is constructed by using two separate cores of the MCF, where the fiber end is cleaved in order to generate strong Fresnel reflection, and independent light coupling between the cores of MCF and the single mode fibers (SMFs) is enabled by the fanin coupler. Vibration gives rise to differential strain variation between cores which results in the modification of phase difference of the interferometer. A narrow linewidth laser is employed, in order to interrogate the phase change induced reflection power variation. Vibration event can be identified and the vibration frequency can be retrieved by processing the measured reflection power with fast Fourier transform (FFT). Broad vibration frequency response range up to 12 kHz (limited by the cutoff frequency of the voltage driver of the vibration source) has been achieved. Performance of the sensor has been shown to be independent of the selection of different core pairs, where the MCF is wound to a piezoelectric transducer (PZT). The proposed in-fiber integrated spatial interferometer does not require any special processing of the fiber (e.g., tapering, splicing, and so forth). The unique sensor structure provides some extraordinary merits, including ultra-compact size, high mechanical strength, high sensitivity and temperature insensitivity.

Characterization and stability measurement of deployed multicore fibers for quantum applications

“…This fact, as already demonstrated in Refs. [25][26][27][28][29], could be quite useful for sensing applications, both classical and quantum.…”

Distributed multicore fiber sensors

“…However, in a MCF that is subjected to bending, the cores at off-center positions will be either stretched or compressed, as shown in Fig. 2 24 . Specifically, the cores on the outer side of the neutral plane will be elongated (e.g.…”

Review of optical fibre sensors for electrical equipment characteristic state parameters detection

“…Then the intensity of the resultant light after interference will be changed. (b) Michelson interferometer (MI) fibre sensor [128,129]. The MI fibre sensor works in a reflection mode, as shown in Fig.…”

“…The sensor element will expand under the influence of vibration or ultrasonic, thus resulting in a phase change of the light propagating in sensing arm. Then the intensity of the resultant light after interference will be changed. (b) Michelson interferometer (MI) fibre sensor [128, 129]. The MI fibre sensor works in a reflection mode, as shown in Fig.…”