Rayleigh backscattering based macrobending single mode fiber for distributed refractive index sensing

241

Distributed optical fiber sensors (DOFS) offer unprecedented features, the most unique one of which is the ability of monitoring variations of the physical and chemical parameters with spatial continuity along the fiber. Among all these distributed sensing techniques, optical frequency domain reflectometry (OFDR) has been given tremendous attention because of its high spatial resolution and large dynamic range. In addition, DOFS based on OFDR have been used to sense many parameters. In this review, we will survey the key technologies for improving sensing range, spatial resolution and sensing performance in DOFS based on OFDR. We also introduce the sensing mechanisms and the applications of DOFS based on OFDR including strain, stress, vibration, temperature, 3D shape, flow, refractive index, magnetic field, radiation, gas and so on.

Section: Distributed Optical Fiber Sensing Based On Ofdrmentioning

confidence: 99%

“…The locations of two macro-bending SMF are 12.2 mm and 11.3 mm, respectively. ( b ) The RI measurement sensitivities curves at location of 11.2 m and 12.8 m (Reprinted from Du et al [ 68 ] with permission of Elsevier; copyright (2017)).…”

Section: Figurementioning

confidence: 99%

Distributed Optical Fiber Sensors Based on Optical Frequency Domain Reflectometry: A review

Ding

Wang

Liu

et al. 2018

241

“…A few distributed magnetic field sensors based on MF have been covered. There are a few studies on the distributed refractive index sensing [76]. Du et al detected the refractive index of the external medium surrounding the fiber by analyzing the Rayleigh backscattering signals, wherein the OFDR technique is adopted.…”

Section: Magnetic Field Optical Sensorsmentioning

confidence: 99%

Recent Progress on Electromagnetic Field Measurement Based on Optical Sensors

Peng

Jia

Bian

et al. 2019

Electromagnetic field sensors are widely used in various areas. In recent years, great progress has been made in the optical sensing technique for electromagnetic field measurement, and varieties of corresponding sensors have been proposed. Types of magnetic field optical sensors were presented, including probes-based Faraday effect, magnetostrictive materials, and magnetic fluid. The sensing system-based Faraday effect is complex, and the sensors are mostly used in intensive magnetic field measurement. Magnetic field optical sensors based on magnetic fluid have high sensitivity compared to that based on magnetostrictive materials. Three types of electric field optical sensors are presented, including the sensor probes based on electric-optic crystal, piezoelectric materials, and electrostatic attraction. The majority of sensors are developed using the sensing scheme of combining the LiNbO3 crystal and optical fiber interferometer due to the good electro-optic properties of the crystal. The piezoelectric materials-based electric field sensors have simple structure and easy fabrication, but it is not suitable for weak electric field measurement. The sensing principle based on electrostatic attraction is less commonly-used sensing methods. This review aims at presenting the advances in optical sensing technology for electromagnetic field measurement, analyzing the principles of different types of sensors and discussing each advantage and disadvantage, as well as the future outlook on the performance improvement of sensors.

“…Since an etched grating introduces a dependence of its properties on refractive index, an etched CFBG, following Equations (1)–(3) introduces a dependence on the refractive index of each grating slice, similarly to a temperature pattern estimation. Whereas in the development of a biosensor this can act as a complication, as the refractive index events can be encoded in any part of the grating (despite the recent work of Du et al [ 119 ] opens interesting avenues for distributed refractive index sensing), it is possible to use an etched CFBG for the detection of step-changes of refractive index along the grating, namely for the detection of liquid level.…”

Section: Applications Of Cfbg Sensorsmentioning

confidence: 99%

Review of Chirped Fiber Bragg Grating (CFBG) Fiber-Optic Sensors and Their Applications

Tosi

2018

137

Fiber Bragg Gratings (FBGs) are one of the most popular technology within fiber-optic sensors, and they allow the measurement of mechanical, thermal, and physical parameters. In recent years, a strong emphasis has been placed on the fabrication and application of chirped FBGs (CFBGs), which are characterized by a non-uniform modulation of the refractive index within the core of an optical fiber. A CFBG behaves as a cascade of FBGs, each one reflecting a narrow spectrum that depends on temperature and/or strain. The key characteristic of CFBGs is that their reflection spectrum depends on the strain/temperature observed in each section of the grating; thus, they enable a short-length distributed sensing, whereas it is possible to detect spatially resolved variations of temperature or strain with resolution on the order of a millimeter over the grating length. Based on this premise, CFBGs have found important applications in healthcare, mechanical engineering, and shock waves analysis, among others. This work reviews the present and emerging trends in CFBG sensors, focusing on all aspects of the sensing element and outlining the application case scenarios for which CFBG sensors have been demonstrated.