scholarly journals Ultra-Sensitive Intensity Modulated Strain Sensor by Tapered Thin-Core Fiber Based Modal Interferometer

Photonics ◽  
2021 ◽  
Vol 8 (9) ◽  
pp. 372
Author(s):  
Chuanxu Liu ◽  
Dexue Sun ◽  
Jiuru Yang ◽  
Hui Zhang ◽  
Lingling Ran
Keyword(s):  
Light Field ◽  
Axial Strain ◽  
Beam Propagation Method ◽  
Temperature Response ◽  
Strain Sensor ◽  
Quantitative Relationship ◽  
Wavelength Shift ◽  
Strain Response ◽  
Core Fiber ◽  
Intensity Loss

In this paper, to enhance practicality, a novel tapered thin-core fiber (t-TCF) based modal interferometer is proposed and demonstrated experimentally. The light field distribution of t-TCF structure is investigated by a beam propagation method, and the quantitative relationship is gained between light intensity loss and waist diameter. Under ~30 μm waist diameter, multiple t-TCF based sensor heads are fabricated by arc-discharged splicing and taper techniques, and comprehensive tests are performed with respects to axial strain and temperature. The experimental results show that, with near-zero wavelength shift, obvious intensity strain response is exhibited and negative-proportional to the reduced length of TCF. Thus, the maximum sensitivity reaches 0.119 dB/με when the TCF length is equal to 15 mm, and a sub-micro-strain detection resolution (about 0.084 με) is obtained. Besides, owing to the flat red-shifted temperature response, the calculated cross-sensitivity of our sensor is compressed within 0.32 με/°C, which is promising for high precision strain related engineering applications.

Spring-Steel Pipe Fiber Bragg Grating Strain Sensor

2014 ◽  
Vol 620 ◽  
pp. 233-237
Author(s):  
Li Peng ◽  
Chuan Li ◽  
Zhen Gang Zhao ◽  
Sheng Wu ◽  
Ying Na Li
Keyword(s):  
Fiber Bragg Grating ◽  
Axial Strain ◽  
Strain Sensor ◽  
Optical Loss ◽  
Spring Steel ◽  
Steel Pipe ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Repeatability Error ◽  
The Stability

Structure’s strain reflects the stability of the project, the excessive structural strain will destroy the stability of the structure. Fiber Bragg Grating has many features, such as, strong anti-interference ability, low optical loss, and it can be used for a long time in the project, etc. Base on the features, the Fiber Bragg Grating Strain Sensor can be used in slope and other projects for the long-term monitoring. In this paper, we develop a Fiber Bragg Grating Strain Sensor based on the spring-steel pipe, FBG be fixed to the inner of the steel pipe by epoxy glue, it is protected by a stainless steel pipe outside, the Flange be fixed to the both side of the spring-steel pipe. When the tension acting one the flanges, the spring-steel pipe occurs an axial strain, this axial strain makes the center wavelength of the Fiber Bragg Grating change, measuring the wavelength shift amount of the Fiber Bragg Grating can calculate the strain. The loading experiment indicates that the sensitivity of the Spring-steel pipe Fiber Bragg Grating Strain Sensor is 0.81pm/με, the linearity of the sensor is 2.1%FS, and the repeatability error of the sensor is 2.29%FS.

scholarly journals Complex Wavefront Shaping through a Multi-Core Fiber

2021 ◽  
Vol 11 (9) ◽  
pp. 3949
Author(s):  
Jiawei Sun ◽  
Nektarios Koukourakis ◽  
Jürgen W. Czarske
Keyword(s):  
Phase Retrieval ◽  
Light Field ◽  
Discrete Distribution ◽  
Cell Manipulation ◽  
Retrieval Algorithm ◽  
Optical Cell ◽  
Loop Control ◽  
Wavefront Shaping ◽  
Core Fiber ◽  
Phase Retrieval Algorithm

Wavefront shaping through a multi-core fiber (MCF) is turning into an attractive method for endoscopic imaging and optical cell-manipulation on a chip. However, the discrete distribution and the low number of cores induce pixelated phase modulation, becoming an obstacle for delivering complex light field distributions through MCFs. We demonstrate a novel phase retrieval algorithm named Core–Gerchberg–Saxton (Core-GS) employing the captured core distribution map to retrieve tailored modulation hologram for the targeted intensity distribution at the distal far-field. Complex light fields are reconstructed through MCFs with high fidelity up to 96.2%. Closed-loop control with experimental feedback denotes the capability of the Core-GS algorithm for precise intensity manipulation of the reconstructed light field. Core-GS provides a robust way for wavefront shaping through MCFs; it facilitates the MCF becoming a vital waveguide in endoscopic and lab-on-a-chip applications.

scholarly journals The relationship between photometric and spectroscopic oscillation amplitudes from 3D stellar atmosphere simulations

2021 ◽  
Author(s):  
Yixiao Zhou ◽  
Thomas Nordlander ◽  
Luca Casagrande ◽  
Meridith Joyce ◽  
Yaguang Li ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Three Dimensional ◽  
Quantitative Relationship ◽  
Stellar Atmospheres ◽  
Spectral Lines ◽  
Wavelength Shift ◽  
The Sun ◽  
Theoretical Derivation ◽  
Velocity Amplitude ◽  
Good Agreement

Abstract We establish a quantitative relationship between photometric and spectroscopic detections of solar-like oscillations using ab initio, three-dimensional (3D), hydrodynamical numerical simulations of stellar atmospheres. We present a theoretical derivation as proof of concept for our method. We perform realistic spectral line formation calculations to quantify the ratio between luminosity and radial velocity amplitude for two case studies: the Sun and the red giant ε Tau. Luminosity amplitudes are computed based on the bolometric flux predicted by 3D simulations with granulation background modelled the same way as asteroseismic observations. Radial velocity amplitudes are determined from the wavelength shift of synthesized spectral lines with methods closely resembling those used in BiSON and SONG observations. Consequently, the theoretical luminosity to radial velocity amplitude ratios are directly comparable with corresponding observations. For the Sun, we predict theoretical ratios of 21.0 and 23.7 ppm/[m s−1] from BiSON and SONG respectively, in good agreement with observations 19.1 and 21.6 ppm/[m s−1]. For ε Tau, we predict K2 and SONG ratios of 48.4 ppm/[m s−1], again in good agreement with observations 42.2 ppm/[m s−1], and much improved over the result from conventional empirical scaling relations which gives 23.2 ppm/[m s−1]. This study thus opens the path towards a quantitative understanding of solar-like oscillations, via detailed modelling of 3D stellar atmospheres.

scholarly journals Perrogator: A Portable Energy-Efficient Interrogator for Dynamic Monitoring of Wavelength-Based Sensors in Wearable Applications

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2962 ◽  
Author(s):  
Camilo A. R. Diaz ◽  
Arnaldo Gomes Leal-Junior ◽  
Letícia M. Avellar ◽  
Paulo F. C. Antunes ◽  
Maria J. Pontes ◽  
...  
Keyword(s):  
Optical Sensors ◽  
Energy Efficient ◽  
Axial Strain ◽  
Healthy Person ◽  
Tunable Filter ◽  
Dynamic Monitoring ◽  
Wavelength Shift ◽  
Knee Angle ◽  
Single Board Computer ◽  
Good Agreement

In this paper, we report the development of a portable energy-efficient interrogator (Perrogator) for wavelength-based optical sensors. The interrogator is based on a compact solution encompassing a white light source and the spectral convolution between the sensor and a tunable filter, which is acquired by a photodetector, where a microcontroller has two functions: (i) To control the filter tuning and to (ii) acquire the photodetector signal. Then, the data is sent to a single-board computer for further signal processing. Furthermore, the employed single-board computer has a Wi-Fi module, which can be used to send the sensors data to the cloud. The proposed approach resulted in an interrogator with a resolution as high as 3.82 pm (for 15.64 nm sweeping range) and maximum acquisition frequency of about 210 Hz (with lower resolution ~15.30 pm). Perrogator was compared with a commercial fiber Bragg grating (FBG) interrogator for strain measurements and good agreement between both devices was found (1.226 pm/µε for the commercial interrogator and 1.201 pm/µε for the proposed approach with root mean square error of 0.0144 and 0.0153, respectively), where the Perrogator has the additional advantages of lower cost, higher portability and lower energy consumption. In order to demonstrate such advantages in conjunction with the high acquisition frequency allowed us to demonstrate two wearable applications using the proposed interrogation device over FBG and Fabry-Perot interferometer (FPI) sensors. In the first application, an FBG-embedded smart textile for knee angle assessment was used to analyze the gait of a healthy person. Due to the capability of reconstructing the FBG spectra, it was possible to employ a technique based on the FBG wavelength shift and reflectivity to decouple the effects of the bending angle and axial strain on the FBG response. The measurement of the knee angle as well as the estimation of the angular and axial displacements on the grating that can be correlated to the variations of the knee center of rotation were performed. In the second application, a FPI was embedded in a chest band for simultaneous measurement of breath and heart rates, where good agreement (error below 5%) was found with the reference sensors in all analyzed cases.

Prediction of Stress-Strain Response Using Rotational Multiple Yield Surface Framework in Malaysian Residual Soil

2020 ◽  
Vol 843 ◽  
pp. 132-137
Author(s):  
Asmidar Alias ◽  
Mohd Jamaludin Md Noor ◽  
Abdul Samad Abdul Rahman
Keyword(s):  
Shear Strength ◽  
Effective Stress ◽  
Volume Change ◽  
Yield Surface ◽  
Axial Strain ◽  
The Body ◽  
Residual Soil ◽  
Strain Response ◽  
Stress Strain ◽  
Soil Volume

Soil settlement is normally quantified using conventional soil volume change models which are solely based on the effective stress and the role of shear strength is ignored due to the difficulties to incorporate in the framework. The Rotational Multiple Yield Surface Framework (RMYSF) is a soil volume change model developed from the standpoint of the interaction between the effective stress and shear strength. RMYSF incorporates the development of mobilised shear strength within the body of the soil whenever the soil is subjected to anisotropic compression. Currently the framework has been applied to predict the soil anisotropic stress-strain behaviour at any effective stress. This paper present the enhancement of this volume change framework using normalisation of axial strain with the understanding that the failure axial strain is not unique, but increases as the effective stress increases. This technique has essentially produced a better accuracy in the prediction of the stress-strain response for Malaysian residual soils. A series of drained tri-axial tests under various effective stresses has been conducted using specimens of 50mm diameter and 100mm height and from the stress-strain curves the inherent mobilised shear strength envelopes at various axial strains have been determined. These mobilised shear strength envelopes were then applied for the prediction of the soil stress-strain response. An excellent agreement between the predicted and the actual stress-strain curves has been achieved.

Strain sensor based on two concatenated abrupt-tapers in twin-core fiber

2018 ◽  
Vol 46 ◽  
pp. 1-4 ◽  
Author(s):  
Yuanyuan Hu ◽  
Tigang Ning ◽  
Chuanbiao Zhang ◽  
Jingjing Zheng ◽  
Li Pei ◽  
...  
Keyword(s):  
Strain Sensor ◽  
Core Fiber

A Magnetic Microsensor with Temperature Compensation Based on Optical Mechatronic Technology

2010 ◽  
Vol 670 ◽  
pp. 164-170
Author(s):  
Chi Chih Lai ◽  
I Nan Chang ◽  
Hsing Cheng Chang ◽  
Chang Chou Hwang ◽  
Wen Fung Liu ◽  
...  
Keyword(s):  
Temperature Compensation ◽  
Magnetic Force ◽  
Coupling Effect ◽  
Magnetic Measurement ◽  
Temperature Response ◽  
Wavelength Shift ◽  
Microelectromechanical System ◽  
Bending Mechanism ◽  
Related Stress ◽  
Magnetic Strength

An optical mechatronic magnetic microsensor with temperature compensation based on fiber Bragg grating (FBG) and microelectromechanical system (MEMS) technologies is demonstrated. Parallel nickel-electroplated cantilever beams are fabricated as an attractive bending mechanism for pushing the optical fiber. Related stress induced cantilever bend caused by magnetic force driving reflective wavelength shift that exactly corresponds with photo-elastic coupling effect to characterize microsensors. Two different cycles of gratings in the same fiber have fabricated to perform the function of magnetic sensing and temperature compensation for reducing temperature-induced bias in magnetic measurement automatically. The sensitivity of 2.238 T/nm with null temperature response has obtained which excited by Nd-Fe-B magnets with residual magnetic strength up to 1.26 Tesla.

scholarly journals Study on Train Wheel Out-of-Roundness Monitoring Method by PVDF Sensing Technology

2014 ◽  
Vol 8 (1) ◽  
pp. 77-80
Author(s):  
Ying Song ◽  
Zhichen Wang ◽  
Yanliang Du
Keyword(s):  
Visual Inspection ◽  
Strain Sensor ◽  
Condition Index ◽  
Contact Forces ◽  
Strain Response ◽  
Element Analysis ◽  
Monitoring Method ◽  
Sensing Technology ◽  
Train Speed ◽  
Set Up

Wheel out-of-roundness (OOR) inevitably jeopardizes the safety of railway operations. Regular visual inspection and checking by experienced workers are the commonly adopted practices to identify wheel defects. However, the defects may not be spotted timely. The paper puts forward a new method of real-time monitor wheel OOR based on PVDF strain sensor. In this method, the track strain response upon wheel-rail interaction is measured and processed to generate a condition index which directly reflects the wheel condition. Firstly, theoretical model of relationship between PVDF sensor output and wheel/rail loads was set up, and the principle for measuring vertical wheel/rail contact forces was proposed. Secondly, the effects of horizontal wheel/rail force and train speed on the output results have been discussed. Finally, this approach was verified by finite element analysis, and the preliminary results showed that this electromagnetic-immune system provides an effective alternative for wheel defects’ detection.

Sign in / Sign up

Export Citation Format

Share Document