scholarly journals Self-Imaging Effect in Liquid-Filled Hollow-Core Capillary Waveguide for Sensing Applications

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 135 ◽  
Author(s):  
Yijian Huang ◽  
Shuhui Liu ◽  
Lichao Zhang ◽  
Yiping Wang ◽  
Ying Wang
Keyword(s):  
Simple Structure ◽  
Low Cost ◽  
High Sensitivity ◽  
Single Mode ◽  
Fiber Optic Sensor ◽  
Hollow Core ◽  
Sensing Applications ◽  
Index Matching ◽  
Potential Applications ◽  
Physical And Chemical

A high sensitivity fiber-optic sensor based on self-imaging effect in a hollow-core capillary waveguide (HCCW) is presented for sensing applications. The sensor is composed of a section of HCCW fusion spliced between single mode fibers (SMFs). The self-imaging effect in the HCCW is investigated with different fiber lengths and arc-fusion parameters. By infiltrating the hollow core with index matching liquids, the peak wavelength of the proposed device shifts towards longer wavelengths. The temperature and refractive index (RI) responses of the sensor are studied systematically. When temperature is increased from 25 °C to 75 °C, the temperature sensitivity of the device can be improved significantly with the infiltrated structure, and reaches −0.49 nm/°C, compared with that of the un-filled device, which is 9.8 pm/°C. For the RI response, the liquid-filled structure achieves sensitivity of 12,005 nm/RIU in the range between 1.448 and 1.450, slightly higher than the 11,920 nm/RIU achieved by the un-filled one. The proposed sensor exhibits the advantages of simple structure, high sensitivity and low cost, which may find potential applications in physical and chemical sensing.

scholarly journals Sensitivity Enhancement of Curvature Fiber Sensor Based on Polymer-Coated Capillary Hollow-Core Fiber

Sensors ◽  
2020 ◽  
Vol 20 (13) ◽  
pp. 3763 ◽  
Author(s):  
Luis A. Herrera-Piad ◽  
Iván Hernández-Romano ◽  
Daniel A. May-Arrioja ◽  
Vladimir P. Minkovich ◽  
Miguel Torres-Cisneros
Keyword(s):  
Fiber Optic ◽  
High Sensitivity ◽  
Single Mode ◽  
Cost Effective ◽  
Fiber Optic Sensor ◽  
Hollow Core ◽  
Sensing Applications ◽  
Optic Sensor ◽  
Wide Range ◽  
Core Fiber

In this paper, we propose and experimentally demonstrate a simple technique to enhance the curvature sensitivity of a bending fiber optic sensor based on anti-resonant reflecting optical waveguide (ARROW) guidance. The sensing structure is assembled by splicing a segment of capillary hollow-core fiber (CHCF) between two single-mode fibers (SMF), and the device is set on a steel sheet for measuring different curvatures. Without any surface treatment, the ARROW sensor exhibits a curvature sensitivity of 1.6 dB/m−1 in a curvature range from 0 to 2.14 m−1. By carefully coating half of the CHCF length with polydimethylsiloxane (PDMS), the curvature sensitivity of the ARROW sensor is enhanced to −5.62 dB/m−1, as well as an increment in the curvature range (from 0 to 2.68 m−1). Moreover, the covered device exhibits a low-temperature sensitivity (0.038 dB/°C), meaning that temperature fluctuations do not compromise the bending fiber optic sensor operation. The ARROW sensor fabricated with this technique has high sensitivity and a wide range for curvature measurements, with the advantage that the technique is cost-effective and easy to implement. All these features make this technique appealing for real sensing applications, such as structural health monitoring.

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 INVESTIGATING THE EFFECT OF TAPER LENGTH ON SENSITIVITY OF THE TAPERED-FIBER BASED TEMPERATURE SENSOR

2016 ◽  
Vol 78 (3) ◽  
Author(s):  
Baktiar Musa ◽  
Yasmin Mustapha Kamil ◽  
Muhammad Hafiz Abu Bakar ◽  
Ahmad Shukri Mohd Noor ◽  
Alyani Ismail ◽  
...  
Keyword(s):  
Temperature Sensor ◽  
Optimum Parameter ◽  
Low Cost ◽  
High Sensitivity ◽  
Single Mode ◽  
Careful Selection ◽  
Tapered Fiber ◽  
Tapered Optical Fiber ◽  
Good Repeatability ◽  
Selection Of

A temperature sensor using single-mode tapered fiber is presented. To better understand the behaviour of a tapered optical fiber, transmission experiments with different taper profiles, specifically waist length were performed. The effects of taper profiles on the sensitivity of the sensor were also investigated. It is demonstrated that careful selection of the taper profile can increase the sensitivity of the sensor. In our experiment, a good temperature sensing result was achieved using the optimum parameter. The best sensitivity achieved was 45.5 pm/°C that measured the range of temperature from 30°C to 120°C. The fabricated sensors are easy to fabricate and relatively low cost. Our results indicate that the tapered fiber based temperature sensor has high sensitivity and good repeatability.  

Experimental Research of Strain and Temperature Based on EFPI Sensor

2011 ◽  
Vol 130-134 ◽  
pp. 4185-4188
Author(s):  
Xiu Feng Yang ◽  
Chun Yu Zhang ◽  
Zheng Rong Tong
Keyword(s):  
Low Cost ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Good Reliability ◽  
High Repetition ◽  
Sensing Applications ◽  
Fabry Perot ◽  
Wet Chemical ◽  
The Many ◽  
Multi Mode

An extrinsic Fabry-Perot (F-P) interferometric (EFPI) sensor by using simple etching and fusing method is proposed and demonstrated. The cavity is formed by wet chemical etching of multi-mode fiber (MMF) end face in hydrofluoric acid solutions, and then it is fused to the end of a single-mode fiber (SMF) to form an extrinsic F-P structure. The strain and temperature of EFPI sensor are studied experimentally. The experimental results show that the interference wavelength becomes 2.648nm longer while the strain increases from 0N to 637N, and the strain sensitivity is about 0.004nm/N, and linearity is 0.999. The interference wavelength becomes 0.032nm shorter while the temperature increases from 20°C to 100°C. This kind of sensor has the many advantages of easy fabrication, good reliability, high-repetition, small size, low cost and mass-production, which offers great prospect for sensing applications.

scholarly journals A Micro Bubble Structure Based Fabry–Perot Optical Fiber Strain Sensor with High Sensitivity and Low-Cost Characteristics

Sensors ◽  
2017 ◽  
Vol 17 (3) ◽  
pp. 555 ◽  
Author(s):  
Lu Yan ◽  
Zhiguo Gui ◽  
Guanjun Wang ◽  
Yongquan An ◽  
Jinyu Gu ◽  
...  
Keyword(s):  
Low Cost ◽  
Strain Sensor ◽  
Glass Tube ◽  
High Sensitivity ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Fabry Perot ◽  
Micro Bubble ◽  
Bubble Structure ◽  
Cost Characteristics

A high-sensitivity, low-cost, ultrathin, hollow fiber micro bubble structure was proposed; such a bubble can be used to develop a high-sensitivity strain sensor based on a Fabry–Perot interferometer (FPI). The micro bubble is fabricated at the fiber tip by splicing a glass tube to a single mode fiber (SMF) and then the glass tube is filled with gas in order to expand and form a micro bubble. The sensitivity of the strain sensor with a cavity length of about 155 μm and a bubble wall thickness of about 6 μm was measured to be up to 8.14 pm/μϵ.

scholarly journals Deployment and Comparison of a Low-Cost High-Sensitivity Concentration Meters Using Micro-Optical Resonators

Proceedings ◽  
2020 ◽  
Vol 60 (1) ◽  
pp. 53
Author(s):  
Amir R. Ali ◽  
Maram Wael ◽  
Reem Amr Assal
Keyword(s):  
Chemical Composition ◽  
Morphological Changes ◽  
Low Cost ◽  
High Sensitivity ◽  
Single Mode ◽  
Optical Resonators ◽  
Optical Resonator ◽  
Single Mode Laser ◽  
Varied Chemical ◽  
Very High

Micro-optical resonators have been introduced as sensors in many applications for a wide number of variable types of stimuli due to their very high resolution, high sensitivity, and high-quality factor. In this paper, a novel micro-optical sensor was designed and tested as a concentration meter for chemical composition of a solution. The micro-optical resonator used is based on whispering gallery mode (WGM). This phenomenon appears when a tapered, single-mode laser carrying micro-optical fiber is evanescently coupled with a polymeric or silica micro-optical resonator. The presented sensor shows the change in concentration by experiencing a change in its morphology due to the varied viscosity of its environment. The variation of concentrations or fluid contents results in a change between the radii of the micro-optical resonator. With varied chemical composition and concentration in the tested sample varied infinitesimally small morphological changes are detected. The change in the resonators shape is read as a WGM shift in the resonance transmission spectrum, which is interpreted using a technique called cross-correlation, which compares the output across time to display the shift, which is later translated into distinct concentration levels. The proposed, exceptionally low-cost sensors were able to detect change at very high resolutions allowing better sensitivity along with wider range of variation. Experimental work for detection of ranges of concentrations of variable type of contaminants is presented.

scholarly journals A Bio-Compatible Fiber Optic pH Sensor Based on a Thin Core Interferometric Technique

Photonics ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 11 ◽  
Author(s):  
Magnus Engholm ◽  
Krister Hammarling ◽  
Henrik Andersson ◽  
Mats Sandberg ◽  
Hans-Erik Nilsson
Keyword(s):  
Fiber Optic ◽  
Ph Sensor ◽  
High Sensitivity ◽  
Single Mode ◽  
Measurement Range ◽  
Ph Sensitive ◽  
Fiber Optic Sensor ◽  
Design Parameters ◽  
Sensitive Material ◽  
Interferometric Technique

There is an increasing demand for compact, reliable and versatile sensor concepts for pH-level monitoring within several industrial, chemical as well as bio-medical applications. Many pH sensors concepts have been proposed, however, there is still a need for improved sensor solutions with respect to reliability, durability and miniaturization but also for multiparameter sensing. Here we present a conceptual verification, which includes theoretical simulations as well as experimental evaluation of a fiber optic pH-sensor based on a bio-compatible pH sensitive material not previously used in this context. The fiber optic sensor is based on a Mach-Zehnder interferometric technique, where the pH sensitive material is coated on a short, typically 20-25 mm thin core fiber spliced between two standard single mode fibers. The working principle of the sensor is simulated by using COMSOL Multiphysics. The simulations are used as a guideline for the construction of the sensors that have been experimentally evaluated in different liquids with pH ranging from 1.95 to 11.89. The results are promising, showing the potential for the development of bio-compatible fiber optic pH sensor with short response time, high sensitivity and broad measurement range. The developed sensor concept can find future use in many medical- or bio-chemical applications as well as in environmental monitoring of large areas. Challenges encountered during the sensor development due to variation in the design parameters are discussed.

scholarly journals Temperature-Independent Gas Pressure Sensor with High Birefringence Photonic Crystal Fiber-Based Reflective Lyot Filter

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5312 ◽  
Author(s):  
Bo Huang ◽  
Ying Wang ◽  
Chun Mao
Keyword(s):  
Pressure Sensor ◽  
Simple Structure ◽  
High Sensitivity ◽  
Gas Pressure ◽  
Hollow Core ◽  
Photonic Bandgap Fiber ◽  
High Birefringence ◽  
Crystal Fiber ◽  
Lyot Filter

A novel temperature-independent gas pressure sensor based on a reflective fiber Lyot filter is presented in this paper. The reflective fiber Lyot filter is simply consist of a fiber polarizer and a segment of hollow-core photonic bandgap fiber (HB-PCF). The HB-PCF plays the role of birefringent cavity in the reflective fiber Lyot filter and works as the sensor head in the gas pressure sensor. Experiment results show that the responses of the sensor to gas pressure and temperature are 3.94 nm/MPa and −0.009 nm/°C, indicating that the proposed gas pressure is sensitive to gas pressure rather than temperature. Coupled with the advantages of simple structure, easy manufacture, high sensitivity and temperature independent, the proposed reflective fiber Lyot filter-based gas pressure sensor holds great potential application in the field of gas pressure monitoring.

Single-polarization single-mode hollow-core negative curvature fiber with nested U-type cladding elements

2021 ◽  
Author(s):  
Qiwei Wang ◽  
Shi Qiu ◽  
Jinhui Yuan ◽  
Guiyao Zhou ◽  
Changming Xia ◽  
...  
Keyword(s):  
Negative Curvature ◽  
Extinction Ratio ◽  
Single Mode ◽  
High Order Mode ◽  
Confinement Loss ◽  
Structure Parameters ◽  
Hollow Core ◽  
Propagation Characteristics ◽  
Potential Applications ◽  
Single Polarization

Abstract Hollow-core negative curvature fibers (HC-NCFs) have become one of the research hotspots in the field of optical fiber because of its potential applications in the data and energy transmissions. In this paper, a new kind of single-polarization single-mode HC-NCF with nested U-type cladding elements is proposed. To achieve the single-polarization single-mode transmission, we use two different silica tube thicknesses that satisfy the resonance and anti-resonance conditions on the U-type cladding elements and the cladding tubes, respectively. Besides, the elliptical elements are introduced to achieve good single-mode performance. By studying the influences of the structure parameters on the propagation characteristics, the optimized structure parameters are obtained. The simulation results show that when the wavelength is located at 1550 nm, the single-polarization single-mode transmission is achieved, along with the polarization extinction ratio of 25749 and minimum high-order mode extinction ratio of 174. Furthermore, the confinement loss is only 0.0015 dB/m.

scholarly journals An Ethanol Vapor Sensor Based on a Microfiber with a Quantum-Dot Gel Coating

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 300 ◽  
Author(s):  
Siqi Hu ◽  
Guofeng Yan ◽  
Chunzhou Wu ◽  
Sailing He
Keyword(s):  
Quantum Dot ◽  
Low Cost ◽  
Temperature Response ◽  
High Sensitivity ◽  
Ethanol Vapor ◽  
Fast Response ◽  
Cost System ◽  
Sensing Applications ◽  
Vapor Sensor ◽  
Ethanol Sensing

An ethanol vapor sensor based on a microfiber with a quantum-dot (QD) gel coating is proposed and demonstrated. The QD gel was made from UV glue as the gel matrix and CdSe/ZnS QDs with a concentration of 1 mg/mL. The drawing and coating processes were conducted by using a simple and low-cost system developed for this study. Bending, ethanol sensing, temperature response, and time response tests were carried out, respectively. The experimental results showed that the fabricated sensor had a high sensitivity of −3.3%/ppm, a very low temperature cross-sensitivity of 0.17 ppm/°C, and a fast response time of 1.1 s. The easily fabricated robust structure and the excellent sensing performance render the sensor a promising platform for real ethanol sensing applications.

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