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 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.

scholarly journals Sensing, Actuation, and Control of the SmartX Prototype Morphing Wing in the Wind Tunnel

Actuators ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 107
Author(s):  
Nakash Nazeer ◽  
Xuerui Wang ◽  
Roger M. Groves
Keyword(s):  
Wind Tunnel ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Experimental Testing ◽  
Single Mode ◽  
Fiber Optic Sensor ◽  
Sensor Data ◽  
Random Errors ◽  
Morphing Wing ◽  
Actuator Dynamics

This paper presents a study on trailing edge deflection estimation for the SmartX camber morphing wing demonstrator. This demonstrator integrates the technologies of smart sensing, smart actuation and smart controls using a six module distributed morphing concept. The morphing sequence is brought about by two actuators present at both ends of each of the morphing modules. The deflection estimation is carried out by interrogating optical fibers that are bonded on to the wing’s inner surface. A novel application is demonstrated using this method that utilizes the least amount of sensors for load monitoring purposes. The fiber optic sensor data is used to measure the deflections of the modules in the wind tunnel using a multi-modal fiber optic sensing approach and is compared to the deflections estimated by the actuators. Each module is probed by single-mode optical fibers that contain just four grating sensors and consider both bending and torsional deformations. The fiber optic method in this work combines the principles of hybrid interferometry and FBG spectral sensing. The analysis involves an initial calibration procedure outside the wind tunnel followed by experimental testing in the wind tunnel. This method is shown to experimentally achieve an accuracy of 2.8 mm deflection with an error of 9%. The error sources, including actuator dynamics, random errors, and nonlinear mechanical backlash, are identified and discussed.

scholarly journals Ex-Vivo Measurement of the pH in Aqueous Humor Samples by a Tapered Fiber-Optic Sensor

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5075
Author(s):  
Ondřej Podrazký ◽  
Jan Mrázek ◽  
Jana Proboštová ◽  
Soňa Vytykáčová ◽  
Ivan Kašík ◽  
...  
Keyword(s):  
Cataract Surgery ◽  
Aqueous Humor ◽  
Fiber Optic ◽  
Ex Vivo ◽  
Sol Gel ◽  
Ph Sensor ◽  
Fiber Optic Sensor ◽  
Optic Sensor ◽  
Tapered Optical Fiber ◽  
Practical Demonstration

A practical demonstration of pH measurement in real biological samples with an in-house developed fiber-optic pH sensor system is presented. The sensor uses 8-hydroxypyrene-1,3,6-trisulfonate (HPTS) fluorescent dye as the opto-chemical transducer. The dye is immobilized in a hybrid sol-gel matrix at the tip of a tapered optical fiber. We used 405 nm and 450 nm laser diodes for the dye excitation and a photomultiplier tube as a detector. The sensor was used for the measurement of pH in human aqueous humor samples during cataract surgery. Two groups of patients were tested, one underwent conventional phacoemulsification removal of the lens while the other was subjected to femtosecond laser assisted cataract surgery (FLACS). The precision of the measurement was ±0.04 pH units. The average pH of the aqueous humor of patients subjected to FLACS and those subjected to phacoemulsification were 7.24 ± 0.17 and 7.31 ± 0.20 respectively.

Identification of trespasser from the signatures of buried single mode fiber optic sensor cable

2015 ◽  
Author(s):  
Preetam Suman ◽  
Pallavi Gupta ◽  
Philip B. Kassey ◽  
Neera Saxena ◽  
Yogesh Choudhary ◽  
...  
Keyword(s):  
Fiber Optic ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Fiber Optic Sensor ◽  
Optic Sensor

scholarly journals High-Sensitivity Fiber-Optic Ultrasound Sensors for Medical Imaging Applications

1998 ◽  
Vol 20 (2) ◽  
pp. 103-112 ◽  
Author(s):  
H. Wen ◽  
D.G. Wiesler ◽  
A. Tveten ◽  
B. Danver ◽  
A. Dandridge
Keyword(s):  
Medical Imaging ◽  
Optical Fibers ◽  
Electromagnetic Interference ◽  
Fiber Optic ◽  
High Sensitivity ◽  
Single Mode ◽  
Piezoelectric Sensors ◽  
Single Element ◽  
Bending Radius ◽  
Laser Interferometers

This paper presents several designs of high-sensitivity, compact fiber-optic ultrasound sensors that may be used for medical imaging applications. These sensors translate ultrasonic pulses into strains in single-mode optical fibers, which are measured with fiber-based laser interferometers at high precision. The sensors are simpler and less expensive to make than piezoelectric sensors, and are not susceptible to electromagnetic interference. It is possible to make focal sensors with these designs, and several schemes are discussed. Because of the minimum bending radius of optical fibers, the designs are suitable for single element sensors rather than for arrays.

Automated Fiber-Optic System for Monitoring the Stability of the Pit Quarry Mass and Dumps

2021 ◽  
pp. 19-26
Author(s):  
А.D. Меkhtiyev ◽  
◽  
E.G. Neshina ◽  
P.Sh. Madi ◽  
D.A. Gorokhov ◽  
...  
Keyword(s):  
Rock Mass ◽  
Optical Fiber ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Light Wave ◽  
Single Mode ◽  
Fiber Optic Sensors ◽  
Fiber Optic Sensor ◽  
Laboratory Sample ◽  
Single Mode Optical Fiber

This article ls with the issues related to the development of a system for monitoring the deformation and displacement of the rock mass leading to the collapse of the quarry sides. Monitoring system uses point-to-point fiber-optic sensors. Fiber-optic sensors and control cables of the communication line are made based on the single mode optical fibers, which allows to measure with high accuracy the deformations and displacements of the rock mass at a distance of 30-50 km. To create fiber-optic pressure sensors, an optical fiber of the ITU-T G. 652.D standard is used. Laboratory sample is developed concerning the point fiber-optic sensor made based on the two-arm Mach-Zender interferometer using a single mode optical fiber for monitoring strain (displacements) with a change in the sensitivity and a reduced influence of temperature interference leading to zero drift. The article presents a mathematical apparatus for calculating the intensity of radiation of a light wave passing through an optical fiber with and without mechanical stress. A laboratory sample of single mode optical fibers based on the Mach-Zender interferometer showed a fairly high linearity and accuracy in the measurement and can be used to control the strain of the mass after appropriate refinement of its design. Mathematical expressions are also given for determining the intensity of the light wave when the distance between the fixing points of a single mode optical fiber changes depending on the change in the external temperature. A diagram for measuring strain using a point fiber-optic strain sensor is developed. Hardware and software package is developed, which can be used to perform a number of settings of measuring channels. The work is aimed at solving the production problems of the Kenzhem quarry of AK Altynalmas JSC.

scholarly journals Preparation and Characterization of Microsphere ZnO ALD Coating Dedicated for the Fiber-Optic Refractive Index Sensor

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 306 ◽  
Author(s):  
Paulina Listewnik ◽  
Marzena Hirsch ◽  
Przemysław Struk ◽  
Matthieu Weber ◽  
Mikhael Bechelany ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Fiber ◽  
Fiber Optic ◽  
Single Mode ◽  
Atomic Layer ◽  
Fiber Optic Sensor ◽  
Refractive Index Sensor ◽  
Layer Deposition ◽  
Fabry Perot

We report the fabrication of a novel fiber-optic sensor device, based on the use of a microsphere conformally coated with a thin layer of zinc oxide (ZnO) by atomic layer deposition (ALD), and its use as a refractive index sensor. The microsphere was prepared on the tip of a single-mode optical fiber, on which a conformal ZnO thin film of 200 nm was deposited using an ALD process based on diethyl zinc (DEZ) and water at 100 °C. The modified fiber-optic microsphere was examined using scanning electron microscopy and Raman spectroscopy. Theoretical modeling has been carried out to assess the structure performance, and the performed experimental measurements carried out confirmed the enhanced sensing abilities when the microsphere was coated with a ZnO layer. The fabricated refractive index sensor was operating in a reflective mode of a Fabry–Pérot configuration, using a low coherent measurement system. The application of the ALD ZnO coating enabled for a better measurement of the refractive index of samples in the range of the refractive index allowed by the optical fiber. The proof-of-concept results presented in this work open prospects for the sensing community and will promote the use of fiber-optic sensing technologies.

High Sensitivity Humidity Fiber-Optic Sensor Based on All-Agar Fabry–Perot Interferometer

2018 ◽  
Vol 18 (12) ◽  
pp. 4879-4885 ◽  
Author(s):  
Bo Wang ◽  
Jiajun Tian ◽  
Ling Hu ◽  
Yong Yao
Keyword(s):  
Fiber Optic ◽  
High Sensitivity ◽  
Fiber Optic Sensor ◽  
Optic Sensor ◽  
Fabry Perot

Raman distributed temperature fiber-optic sensor based on single-mode fiber

2015 ◽  
Author(s):  
Sun Woo Kim ◽  
Min Seong Seo ◽  
Jung Min Hwang ◽  
Bong-Wan Lee ◽  
Min Yong Jeon
Keyword(s):  
Fiber Optic ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Fiber Optic Sensor ◽  
Optic Sensor
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