Strain, torsion and refractive index sensors based on helical long period fibre grating inscribed in small-core fibre for structural condition monitoring

2021 ◽  
Vol 24 (6) ◽  
pp. 1248-1255
Author(s):  
Cailing Fu ◽  
Yi-Qing Ni ◽  
Tong Sun ◽  
Yiping Wang ◽  
Siqi Ding ◽  
...  
Keyword(s):  
Refractive Index ◽  
High Sensitivity ◽  
Single Mode ◽  
Structural Condition ◽  
Core Diameter ◽  
Small Core ◽  
Long Period ◽  
Sensing Applications ◽  
Core Fibre ◽  
Refractive Index Sensors

This study is intended to develop long period fibre grating sensors for potential applications in environmental and durability monitoring of coastal structures. High-quality helical long period fibre gratings (HLPFGs) are inscribed in different types of small-core single mode fibre (SMF) by use of hydrogen-oxygen flame heating technique. A detailed investigation of the effect of core diameter on their transmission spectrum and optimum length of the HLPFG has been pursued. A longer length is required to achieve the same coupling attenuation in a smaller-core SMF than that of a larger-core fibre. The strain, torsion and refractive index (RI) properties of the HLPFG is investigated experimentally to develop a high-sensitivity sensor. The experimental results show that the strain sensitivity could be enhanced by means of employing a larger-core diameter SMF. Moreover, the HLFPGs are also sensitive to the torsion and external RI. Hence, such HLFPGs have great potential for sensing applications.

scholarly journals High sensitivity refractive index sensor based on a tapered small core single-mode fiber structure

2015 ◽  
Vol 40 (17) ◽  
pp. 4166 ◽  
Author(s):  
Dejun Liu ◽  
Arun Kumar Mallik ◽  
Jinhui Yuan ◽  
Chongxiu Yu ◽  
Gerald Farrell ◽  
...  
Keyword(s):  
Refractive Index ◽  
High Sensitivity ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Refractive Index Sensor ◽  
Fiber Structure ◽  
Small Core

scholarly journals Hybrid Grating in Reduced-Diameter Fiber for Temperature-Calibrated High-Sensitivity Refractive Index Sensing

2019 ◽  
Vol 9 (9) ◽  
pp. 1923
Author(s):  
Biqiang Jiang ◽  
Zhen Hao ◽  
Dingyi Feng ◽  
Kaiming Zhou ◽  
Lin Zhang ◽  
...  
Keyword(s):  
Refractive Index ◽  
Simultaneous Measurement ◽  
Surrounding Medium ◽  
High Sensitivity ◽  
Fiber Grating ◽  
Bragg Resonance ◽  
Core Mode ◽  
Promising Alternative ◽  
Sensing Applications ◽  
Highly Sensitive

We propose and experimentally demonstrate a hybrid grating, in which an excessively tilted fiber grating (Ex-TFG) and a fiber Bragg grating (FBG) were co-inscribed in a reduced-diameter fiber (RDF). The hybrid grating showed strong resonances due to coupling among core mode and a set of polarization-dependent cladding modes. This coupling showed enhanced evanescent fields by the reduced cladding size, thus allowing stronger interaction with the surrounding medium. Moreover, the FBG’s Bragg resonance confined by the thick cladding was exempt from the change of the surrounding medium’s refractive index (RI), and then the FBG can work as a temperature compensator. As a result, the Ex-TFG in RDF promised a highly sensitive RI measurement, with a sensitivity up to ~1224 nm/RIU near the RI of 1.38. Through simultaneous measurement of temperature and RI, the temperature dependence of water’s RI is then determined. Therefore, the proposed hybrid grating with a spectrum of multi-peaks embedded with a sharp Bragg resonance is a promising alternative for the simultaneous measurement of multi-parameters for many RI-based sensing applications.

scholarly journals Reusable TiN Substrate for Surface Plasmon Resonance Heterodyne Phase Interrogation Sensor

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1325 ◽  
Author(s):  
Ru-Jing Sun ◽  
Hung Ji Huang ◽  
Chien-Nan Hsiao ◽  
Yu-Wei Lin ◽  
Bo-Huei Liao ◽  
...  
Keyword(s):  
Refractive Index ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
High Sensitivity ◽  
Nanorod Array ◽  
Glass Substrates ◽  
Sensing Applications ◽  
Bulk Charge ◽  
Phase Interrogation

A TiN-based substrate with high reusability presented high-sensitivity refractive index measurements in a home-built surface plasmon resonance (SPR) heterodyne phase interrogation system. TiN layers with and without additional inclined-deposited TiN (i-TiN) layers on glass substrates reached high bulk charge carrier densities of 1.28 × 1022 and 1.91 × 1022 cm−3, respectively. The additional 1.4 nm i-TiN layer of the nanorod array presented a detection limit of 6.1 × 10−7 RIU and was higher than that of the 46 nm TiN layer at 1.2 × 10−6 RIU when measuring the refractive index of a glucose solution. Furthermore, the long-term durability of the TiN-based substrate demonstrated by multiple processing experiments presented a high potential for various practical sensing applications.

scholarly journals Ultrashort Long-Period Fiber Gratings Inscribed on a Single-Mode Fiber for Torsion Sensing Applications

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Marta Nespereira ◽  
João M. P. Coelho ◽  
José Manuel Rebordão
Keyword(s):  
Single Mode ◽  
Single Mode Fiber ◽  
Wavelength Shift ◽  
Fiber Grating ◽  
Long Period ◽  
Sensing Applications ◽  
High Tension ◽  
Long Period Fiber Gratings ◽  
Order Of Magnitude ◽  
Period Fiber Grating

The response of ultrashort-length CO2-induced long-period fiber grating (LPFG) sensors to torsion is reported. While engraving using CO2 laser radiation, the fiber is submitted to high tension allowing the obtainment of gratings with shorter lengths, down to 2.4 mm, which is almost one order of magnitude lower than the usual. Also, the fiber is only irradiated in one side, creating an asymmetrical profile leading to highly birefringent gratings. Sensitivity to axial twists is demonstrated, with values up to 0.15 nm/(rad/m) for the resonant wavelength shift and higher than 0.03 dBm/(rad/m) for the variation in the intensity (attenuation). Discrimination between rotation directions, clockwise and counterclockwise, was observed.

Long-period grating refractive index sensor with a modified cladding structure for large operational range and high sensitivity

2006 ◽  
Vol 45 (24) ◽  
pp. 6142 ◽  
Author(s):  
Jian Yang ◽  
Li Yang ◽  
Chang-Qing Xu ◽  
Chenglin Xu ◽  
Weiping Huang ◽  
...  
Keyword(s):  
Refractive Index ◽  
High Sensitivity ◽  
Refractive Index Sensor ◽  
Long Period Grating ◽  
Long Period ◽  
Operational Range

scholarly journals Fiber Optic Refractive Index Sensors Based on a Ball Resonator and Optical Backscatter Interrogation

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6199
Author(s):  
Madina Shaimerdenova ◽  
Takhmina Ayupova ◽  
Marzhan Sypabekova ◽  
Daniele Tosi
Keyword(s):  
Refractive Index ◽  
Reflection Spectrum ◽  
Return Loss ◽  
Fiber Optic ◽  
Single Mode ◽  
Wavelength Shift ◽  
Amplitude Change ◽  
Highly Sensitive ◽  
Refractive Index Sensors ◽  
Index Unit

In this work, we introduced fabrication and interrogation of simple and highly sensitive fiber-optic refractive index (RI) sensors based on ball resonators built on the tip of single-mode fibers. The probes have been fabricated through a CO2 fiber splicer, with a fast (~600 s) and repeatable method. The ball resonator acted as a weak interferometer with a return loss below −50 dB and was interrogated with an optical backscatter reflectometer measuring the reflection spectrum. The ball resonators behaved as weak interferometers with a shallow fringe and a spectrum that appeared close to a random signal, and RI sensitivity could be measured either through wavelength shift or amplitude change. In this work, we reported four samples having sensitivity ranges 48.9–403.3 nm/RIU and 256.0–566.2 dB/RIU (RIU = refractive index unit). Ball resonators appeared as a sensitive and robust platform for RI sensing in liquid and can be further functionalized for biosensing.

Sign in / Sign up

Export Citation Format

Share Document