A fiber Bragg grating (FBG) accelerometer based on double diaphragms is presented and experimentally demonstrated. Design, fabrication, optimization of the FBG are analyzed. Experimental results indicate that provides broad flat frequency range from 50 to 800 Hz, corresponding sensitivity 23.8 45.9 pm/G, while flatness <;3 dB. Cross-axis <;2.1% main-axis sensitivity, dynamic resolution can reach 0.385 mG/√(Hz), 80 Random error analyzed by using Allan variance analysis method, which promising...

A compact fiber Bragg grating (FBG) vibration sensor consisting a flat diaphragm and two L-shaped rigid cantilever beams for seismic measurement has been proposed experimentally demonstrated. The specially designed sensing configuration contributes many desirable features such as wide frequency response range (10-120 Hz), an extremely high sensitivity coefficient (~100pm/g) together with robust metal package improving the mechanical strength decreased transverse (<; 5%), making it good...

An in-fiber Mach-Zehnder interferometer (MZI) for high-sensitive refractive index (RI) measurement is proposed and experimentally demonstrated. The sensing head formed by a single-mode fiber (SMF) sandwiched between two short sections of thin-core fibers (TCFs), i.e., TCF-SMF-TCF MZI configuration with length 9 mm. A well-defined interference pattern obtained as the result fiber-core mismatch core-cladding modes interference. selected dip extremely sensitive to ambient RI, providing stable...

Off-axis fiber Bragg gratings are inscribed by ultraviolet irradiation limited to expose only a portion of the core cross section. The coupling cladding modes is significantly increased, and amplitude mode resonances becomes sensitive bending in magnitude direction. Sensitivities ranging from +1.17 dB/m−1 −1.25 were obtained for different directions relative offset direction grating, curvatures 0 1.1 m−1, range ideal shape sensing large structures. sensor response also shown be independent...

Abstract In this work, a compact fiber-optic 3D shape sensor consisting of two serially connected 2° tilted fiber Bragg gratings (TFBGs) is proposed, where the orientations grating planes TFBGs are orthogonal. The measurement reflective transmission spectrum from pair was implemented by Fresnel reflection cleaved end. groups cladding mode resonances in respond differentially to bending, which allows for unique determination magnitude and orientation bend plane (i.e. with ± 180 degree...

We demonstrate a fiber-optic 3D vector displacement sensor based on the monitoring of Bragg reflection from an eccentric grating inscribed in depressed-cladding fiber using femtosecond laser side-illumination and phase-mask technique. The compact sensing probe consists short section depressed cladding (DCF) containing eccentrically positioned gratings. breaks cylindrical symmetry cross-section further has bending orientation-dependence. generated fundamental resonance is strongly sensitive...

We have designed, fabricated, and characterized a fiber-optic three-dimensional vector accelerometer for vibration measurement. The is based on fiber Bragg gratings (FBGs) inscribed with three cores of seven-core by femtosecond laser phase mask. Through monitoring the wavelength shifts two seven cores, we obtain azimuthal angle acceleration in XY plane reconstruction algorithmic calculation. Similarly, shift core fixed along Z-axis, Z-axis direction. full 3D information about signal obtained...

A Sagnac interferometer based on a short section of PANDA fiber for high sensitivity temperature measurement has been proposed and experimentally demonstrated. The principle this is theoretically analyzed by Jones Matrix. Extremely up to <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${-}$</tex></formula> 1.46 nm/ Notation="TeX">$^{\circ}$</tex></formula> C achieved, together with compact size,...

A highly sensitive curvature sensor using an in-fiber Mach-Zehnder interferometer is proposed and experimentally demonstrated. The has a simple configuration-a short section of single-mode fiber sandwiched between two sections multimode fibers to achieve compact interferometer. wavelength shift selected dip in the interference spectrum responds linearly with shows high sensitivity up -14.40±0.02 * m.

An in-fiber quasi-Michelson interferometer working on reflection is proposed and experimentally demonstrated. The device consists of a short section multimode fiber (MMF) followed by single-mode (SMF) whose end face terminated thick silver film. MMF excites cladding modes into downstream SMF via the mismatched-core splicing interface. core-cladding are reflected back film recoupled to core lead-in through MMF. A well-defined interference pattern obtained as result mode interference....

We present a hybrid miniature optical fiber Fabry-Perot interferometer for simultaneous measurement of gas refractive index and temperature. The is fabricated by cascading two short sections capillary tubes with different inner diameters. One extrinsic based on the air gap cavity formed tube large diameter. Another section small diameter performs as an intrinsic also provides channel enabling to enter leave freely. experiment shows that dips or peaks in fringe exhibit responses changes Owing...

The surface plasmon resonance (SPR) performance of gold coated tilted fiber Bragg gratings (TFBG) at near infrared wavelengths is evaluated as a function the angle between tilt plane orientation and direction single- double-sided, nominally 50 nm-thick metal depositions. Scanning electron microscope images show that coating are highly non-uniform around circumference, varying zero nm. In spite these variations, experimental results spectral signature TFBG-SPR sensors similar to simulations...

A simultaneous relative humidity (RH) and temperature sensor based on an optical fiber Fabry-Perot interferometer is proposed experimentally demonstrated. This constructed by splicing a short length of photonic crystal (PCF) to single mode coating ultrathin polyvinyl alcohol film the PCFs cleaved surface. The total this sensing head only ~110 μM compact size means it can be used flexibly in limited space harsh environments. Experimental results demonstrate that simultaneously measure ambient...

In this letter, we proposed a gas refractometer based on optical fiber Fabry-Perot interferometer with an open cavity. The cavity is short section capillary tube spliced between single-mode and side-hole (SHF). unique cladding of the SHF enables entering or leaving freely. measurement pressure-induced refractive index change nitrogen has been demonstrated by monitoring wavelength shift interference pattern. robust microsize architecture make good candidate for sensing applications.

A miniature optical fiber ultrasonic sensor based on the Fabry-Perot interferometer (FPI) is proposed and experimentally demonstrated. The cavity of a section hollow core coated with 353ND diaphragm. well-define interference pattern achieved, spectral sideband filter technique used to interrogate sensor. Because thin reflective diaphragm extremely sensitive sound pressure, signal-to-noise ratio response reaches 31.22 dB pulse excitation 300 kHz. clear interface information can be...

A simple and compact thin-core fiber (TCF)-based Mach-Zehnder interferometer (MZI) is proposed for curvature measurement. The sensor head composed by a short section of TCF embedded between two single-mode fibers. MZI works on the basis interference core mode cladding in TCF. transmission spectrum analyzed fast Fourier transform, which indicates that mainly occurs LP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub>...

In this paper, a polymer polyhexamethylene biguanide (PHMB) based Fabry-Perot (FP) interferometric optical fiber sensor for carbon dioxide gas detection at atmospheric pressure is investigated and experimentally demonstrated. The absorption release of CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> molecules lead to the refractive index change PHMB. length sensitive FP cavity can be easily controlled by using Czochralski method....

A Mach-Zehnder interferometric magnetic field sensor based on a photonic crystal fiber (PCF) and fluid (MF) was designed experimentally demonstrated. The sensing probe consists of single-mode-(SM)-multimode-PCF-SM structure through arc fusion splicing. It then laser engrave notched with the femtosecond so that PCF cladding selectively infilled MF. well-defined interference pattern obtained account tunable refractive index MF cladding. transmission spectra proposed under different intensities...

We have designed and developed a compact fiber optic accelerometer for vibration detection. The mechanical vibrating element is hexagonal structure which fabricated using 3D-printing technology. Such can efficiently convert vertical vibrations into periodic deformations of longitudinally positioned Bragg grating (FBG) inscribed. By demodulating the wavelength shift reflection spectrum, we established relationship between vibrational acceleration shift. measured sensitivity 421.4pm/g. A...

We demonstrate a fiber-optic strain sensor based on seven-core fiber (7-CF) for accurate extrusion bending and tensile sensing. The structure we designed is the 7-CF spliced to piece of multimode each side with lateral core-offset then conventionally fused single mode optical as input output ports. experimental results indicate that optimal curvature sensitivity achieved 25.96 nm/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , 0.094...

A low-flow flowmeter based on the bending measurement of a cladding fiber Bragg grating (CLFBG) has been proposed and demonstrated. The CLFBG is fixed in cantilever beam structure composed spring circular target. femtosecond laser side-illumination technique was utilized to ensure that inscription remains close core–cladding interface multi-cladding (MCLF). resonance presents dependence because asymmetrical distribution along cross section. force exerted target by slow flow rate fluid order...