Extreme Environment Sensing Using Femtosecond Laser-Inscribed Fiber Bragg Gratings

Mihailov, Stephen J.; Grobnic, Dan; Hnatovsky, Cyril; Walker, Raymond W.; Lu, Ping; Coulas, David; Ding, Huimin

doi:10.3390/s17122909

Cited by 110 publications

(65 citation statements)

References 137 publications

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“…At these kind of depths the temperatures can exceed 500°C and extreme pressures are also encountered. In this paper, a short introductory review of high and ultra-high temperature FBG sensors is first presented, following past reviews [6][7][8]. The prefixes 'high' and 'ultra-high' are defined herein for FBG operating temperature conditions below and above 800°C, respectively.…”

Section: Introductionmentioning

confidence: 99%

Overview of high temperature fibre Bragg gratings and potential improvement using highly doped aluminosilicate glass optical fibres

et al. 2019

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In this paper, various types of high temperature fibre Bragg gratings (FBGs) are reviewed, including recent results and advancements in the field. The main motivation of this review is to highlight the potential of fabricating thermally stable refractive index contrasts using femtosecond (fs) nearinfrared radiation in fibres fabricated with non-conventional techniques, such as the molten core method. As a demonstration of this, an yttrium aluminosilicate (YAS) core and pure silica cladding glass optical fibre is fabricated and investigated after being irradiated by an fs laser within the Type II regime. The familiar formation of nanogratings inside both core and cladding regions are identified and studied using birefringence measurements and scanning electron microscopy. The thermal stability of the Type II modifications is then investigated through isochronal annealing experiments (up to T=1100°C; time steps, Δt=30 min). For the YAS core composition, the measured birefringence does not decrease when tested up to 1000°C, while for the SiO 2 cladding under the same conditions, its value decreased by ∼30%. These results suggest that inscription of such 'Type II fs-IR' modifications in YAS fibres could be employed to make FBGs with high thermal stability. This opens the door toward the fabrication of a new range of 'FBG host fibres' suitable for ultra-high temperature operation. ORCID iDsMaxime Cavillon https:/ /orcid.org/0000-0003-1341-6294 Peter Dragic https:/ /orcid.org/0000-0002-4413-9130 Figure 5. Normalized retardance (averaged over the 0.1 to 1.0 μJ pulse energy range) as a function of temperature for YAG-derived fibre at the core center (YAS) and in the cladding (SiO 2 ), for both // and ⊥ configurations. The measurements were performed at room temperature.

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Section: Introductionmentioning

confidence: 99%

Overview of high temperature fibre Bragg gratings and potential improvement using highly doped aluminosilicate glass optical fibres

et al. 2019

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“…The technique produces a highly localized RI change [55] through the high-intensity laser pulse interaction across a tiny region in a shorter time-frame that will result in high-resolution inscription [56]. The fabricated sensors are relatively stable at higher temperatures than conventional UV laser-based sensors [57] because the change of index occurs as a result of high intensity nonlinear multiphoton process, which allows sensors to be durable up to approximately the glass transition temperature (t g ).…”

Section: Inscription Of the Sensing Structurementioning

confidence: 99%

Investigation of a Bragg Grating-Based Fabry–Perot Structure Inscribed Using Femtosecond Laser Micromachining in an Adiabatic Fiber Taper

et al. 2020

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This paper presents the fabrication of a fiber Bragg grating (FBG)-based Fabry–Perot (FP) structure (7 mm total length) in an adiabatic fiber taper, investigates its strain and temperature characteristics, and compares the sensing characteristics with a standard polyimide coated FBG sensor. Firstly, a simulation of the said structure is presented, followed by the fabrication of an adiabatic fiber taper having the outer diameter reduced to 70 μ m (core diameter to 4.7 μ m). Next, the sensing structure, composed of two identical uniform FBG spaced apart by a small gap, is directly inscribed point-by-point using infrared femtosecond laser (fs-laser) micromachining. Lastly, the strain and temperature behavior for a range up to 3400 μ ε and 225 ° C, respectively, are investigated for the fabricated sensor and the FBG, and compared. The fabricated sensor attains a higher strain sensitivity (2.32 pm/ μ ε ) than the FBG (0.73 pm/ μ ε ), while both the sensors experience similar sensitivity to temperature (8.85 pm/ ° C). The potential applications of such sensors include continuous health monitoring where precise strain detection is required.

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“…In this work we focus on a particular class of optical sensors called the Fiber Bragg Gratings (FBGs) [12][13][14][15][16]. They consist in an optical fiber equipped with sensitive spots, able to detect variations of mechanical strain and temperature with very high precision.…”

Section: Fiber Bragg Grating Sensors: Operation and Applicationsmentioning

confidence: 99%

Experimental comparison of Fiber Bragg Grating installation techniques for aerospace systems

2019

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Aircraft systems are becoming more and more complex, as they are required to perform multiple functions. For example, smart systems need to be able to self-monitor their working parameters, in order to infer their health status. All these additional functions require the system to acquire a multitude of measurements; albeit sometimes it is possible to implement virtual sensor techniques, dedicate sensing hardware is usually needed. As a main drawback, the installation of the needed sensors adds up to the total complexity, weight, cost and failure rate of the system. In this context, minimally invasive sensors can be used to measure the system parameters with high spatial resolution and minimal added complexity. One key technology in this field is the Fiber Bragg Gratings (FBG) optical sensors, used to perform strain and temperature measurements. This work describes an experimental campaign intended to assess and validate several installation techniques for FBGs as strain sensors. Two test benches were developed for different measurement setups. One is intended for creep and repeatability tests of a FBG sensor glued at both ends; the other was used to compare point gluing and continuous gluing techniques on an aluminium beam subject to a bending load. Results are compared with numerical simulations of the structure and measurements performed with traditional strain gages.

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Extreme Environment Sensing Using Femtosecond Laser-Inscribed Fiber Bragg Gratings

Cited by 110 publications

References 137 publications

Overview of high temperature fibre Bragg gratings and potential improvement using highly doped aluminosilicate glass optical fibres

Overview of high temperature fibre Bragg gratings and potential improvement using highly doped aluminosilicate glass optical fibres

Investigation of a Bragg Grating-Based Fabry–Perot Structure Inscribed Using Femtosecond Laser Micromachining in an Adiabatic Fiber Taper

Experimental comparison of Fiber Bragg Grating installation techniques for aerospace systems

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