This study investigates the utilization of an in-fiber interferometer embedded in polydimethylsiloxane (PDMS) to develop a highly sensitive tactile sensor. The tapered mode-field mismatch structure is more conducive stimulating strong high order modes promote sensitivity Experimental investigations are conducted sensing performance sensor, resulting 23.636 nm/N and detection limit 0.746 mN. experiments demonstrate that employing fast Fourier transform (FFT) inverse FFT (IFFT) methods filter...

A soft highly sensitive tactile sensor based on an in-fiber interferometer embedded in polydimethylsiloxane (PDMS) structure is studied. Theoretical simulation obtains that the high order sensing modes and PDMS can improve sensitivity. Experiments show different modes, derived by fast Fourier transform (FFT) inverse FFT methods, present performance. Corresponding to mode, 1.3593 nm/kPa sensitivity 37 Pa (0.015 N) detection limit obtained. Meanwhile, it also shows very good stability,...

An optical fiber interferometric refractometer for alcohol gas concentration and low refractive index (RI) solution (with 1.33–1.38 RI range) measurement is theoretically experimentally demonstrated. The based on a single-mode thin-core (STS) structure. By embedding suitably sized air cavity at the splicing point, high-order cladding modes are successfully excited, which makes sensor more suitable measurement. effect of cavity’s diameter sensitivity was analyzed experimentally, proved that...

An ultrasensitive micronewton force optical sensor based on a tapered fiber Mach-Zehnder interferometer (MZI) embedded in polydimethylsiloxane (PDMS) is studied. Benefited from the methods of non-adiabatic tapering combined with mode field mismatch between different fibers, both which can excite high order modes, achieves sensitivity up to 0.194 nm/mN and low detection limit 103 μN. Meanwhile, this possesses longer effective interference length narrower free spectral range (FSR) than other...

Abstract Before saturated absorption, graphene possesses optical nonlinear refractive index, which is a photoinduced index effect. Taking advantage of this effect, wavelength tunable filter realized based on filled all fiber Fabry‐Pérot microcavity. Experimental results show that the interference exhibits linear red‐shift with increase tunning power and efficiency increases cavity length thickness. In study, maximum vs can get 66 pm/mW. This has advantages high efficiency, simple structure,...

Abstract In view of the problem that sensing characteristics multi-mode interferometric fiber sensors cannot be accurately analyzed, an analysis method based on fast Fourier transform (FFT) and inverse (IFFT) is proposed demonstrated theoretically experimentally. The suitabilities rectangular window function with narrow main lobe (high spectrum resolution) low side mode energy leakage) Hanning wide (low high concentration) in this kind sensor are discussed, respectively. This can not only...

Abstract As a high-resolution sensor, it is very important to improve the spectral stability of microfiber Sagnac loop interferometer. A fiber Bragg grating (FBG) mode selecting method proposed and demonstrated. The can filter out some cladding modes by FBG in make working energy more concentrated, which shows that interference spectrum becomes uniform. At same time, sensitivity linearity sensor be improved slightly this method. In our experiment, resolution get 1.41 × 10 -5 ∼ 7.49 -6 liquid...

Large standoff magnetometry (LSM) is an emerging non-intrusive, above-ground, passive geo-magnetization flux leakage measurement technology to detect pipeline features or anomalies associated with elevated stresses. Although many promising field trial results have been reported in the past, its overall performance still has not reached sufficient consistency and reliability. This paper presents PG&E’s effort gaining some fundamental understanding of current LSM qualitative &...

Graphene exhibits a particular optical polarization dependence property, which is that supporting states of graphene can be readily altered through tuning the polarity imaginary part its conductivity. The in-fiber Mach–Zehnder interferometer (MZI) possesses extremely high sensitivity to surrounding refractive index cladding modes. Combining and interferometer, graphene-optical fiber hybrid MZI constructed. Depending on interference wavelength expresses periodic drift with light linear angle...

Abstract Large standoff magnetometry (LSM) as a non-intrusive NDE technology has been used many years in commercial trials for above-ground detection of underground pipeline anomalies associated with stress concentration zones (SCZs). As passive geo-magnetization flux leakage measurement method, it mainly targeting common such corrosion, gouges/dents and cracks that are often very localized small scale. Insufficient consistency reliability still the major concern due to technical challenges...

A temperature-insensitive all fiber Fabry–Pérot (F–P) and Mach–Zehnder (M–Z) hybrid compact structure its sensing characteristics are proposed theoretically experimentally demonstrated. In one sensor, two kinds of principles existing, which is shown in the process that with increase refractive index (RI) liquid, dip wavelengths coming from F–P interference do red-drift, dips M–Z blue-drift, respectively. Due to opposite shift almost same temperature sensitivities, difference between...

An air pressure sensor is demonstrated based on a closed micro-cavity F-P (Fabry-Perot) optical fiber interferent sensing structure. The wavelengths present red-shift with the increase. Its sensitivity can get 1.271nm/MPa for linear fitting of experiment results.

There are more and people-centered devices around the world, so people's attention to flexible robots is gradually increasing, this drives development of sensors. By understanding background fiber elastic sensor, an all-optical curvature sensor proposed, which composed a polydimethylsiloxane(PDMS) material encapsulated Mach-Zehnder interferometer(MZI), worn different fingers can produce wavelength drift phenomenon. It small in volume, light weight, without electromagnetic interference, high...

An all-fiber dynamic sound pressure sensor based on Mach-Zehnder interferometer(MZI) encapsulated with the Poly Ethylene Terephthalate (PET) diaphragm is composed. The relationships between material, size, thickness of and sensitivity are analyzed theoretically. simulation results show that shape variable increases as radius decrease under condition small deflection theorem, resulting in a good linear relationship diaphragm. can be widely used detection, signal collection, recovery.

Abstract Applications of a novel 3-D mapping and visualization technology for underground natural gas plastic/metallic pipelines improving pipeline assets management beyond the capability other known technologies are presented. The developed is based on combining Radar Forced-Resonance-Imaging (FRI) principles referred to as Bakhtar Buried Pipe Detector (BPD) with its original platform under US Air Force SBIR programs “BakhtarRadar”. This extremely low-power (≤ 10 dBm) detection volumetric...

A Sagnac loop liquid refractive index sensor is proposed based on SMF-Tapered TCF-SMF (STS) and FBG. In the range of 1.333-1.3465 1.3515-1.363, sensitivity 5521.6nm/RIU 7173.8nm/RIU, respectively. By cascading FBG, random fluctuation wavelength reduced from±0.862nm to 0.004nm. It can effectively filter out part cladding mode improve stability sensor.

A comb filter based on microfiber Sagnac ring is proposed. The transmission spectrum of the proposed theoretically analyzed. And polarization characteristics are experimentally demonstrated. experimental results show that variation angle will cause drift and depth variation. wave peak intensity approximately sinusoidal waveforms through rotating controller. By studying filter, can be better applied to dense wavelength division multiplexing system.