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Applied Sciences
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Recent Progress in Fiber Optic Sensors: Bringing Light to Measurement
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Recent Progress in Fiber Optic Sensors: Bringing Light to Measurement

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Optics and Lasers".

Deadline for manuscript submissions: closed (30 June 2019) | Viewed by 66015

Special Issue Editors

Dr. Qiang Wu

E-Mail Website
Guest Editor
Physics and Electrical Engineering, Northumbria University, Newcastle Upon Tyne NE1 8ST, UK
Interests: optical fiber interferometers for novel fiber optical couplers and sensors; nanofiber; microsphere sensors for bio-chemical sensing; the design and fabrication of fiber bragg grating devices and their applications for sensing; nonlinear fibre optics; surface plasmon resonant and surface acoustic wave sensors
Special Issues, Collections and Topics in MDPI journals
Prof. Liyang Shao

E-Mail Website
Guest Editor
Department of Electrical and Electronic Engineering, Southern University of Science and Technology of China, Shenzhen 518055, China
Interests: fiber grating and sensors; distributed fiber optic sensing; microwave photonics for sensing; smart sensing systems for railway industry
Dr. Serhiy Korposh

E-Mail Website
Guest Editor
Department of Electrical and Electronic Engineering, The University of Nottingham, Nottingham NG7 2RD, UK

Special Issue Information

Dear Colleagues,

Fibre optic sensors have shown great intrinsic advantages over their electronic counterparts, such as high sensitivity, environmental ruggedness, long distance remote operation and real-time monitoring capability. Optical fibre sensors show great potential for applications involving measurements from the macro world to the micro. This Special Issue on fibre optic sensors invites original unpublished papers demonstrating recent advances and developments in novel concepts, structures, theories, materials and applications for fibre optic sensors and systems. We encourage submission of papers reviewing recently obtained results, addressing current challenges, novel structures and techniques, and applications of fibre optic sensors and systems. Potential topics include, but are not limited to, the recent advances in the following areas:

  • Physical, mechanical, acoustic and electro-magnetic sensors
  • Chemical, gas, biological, environmental and medical sensors
  • Micro structure and nanophotonic sensors
  • Gyroscopes, interferometric and polarimetric sensors
  • Multiplexing and distributed sensing
  • Sensor interrogation techniques and sensor systems
  • Surface plasmon resonant sensors
  • Sensor network and field tests
  • Novel concept for fibre sensors
  • Commercialization development of sensors

Dr. Qiang Wu
Prof. Liyang Shao
Dr. Serhiy Korposh
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Applied Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Optical fiber
  • Physical sensors
  • Chemical sensors
  • Biosensors
  • Fiber grating
  • Disbributed sensing
  • Photonic crystal fiber
  • Interferometer
  • Micro structure
  • nanophotonic
  • Sensor interrogation techniques
  • Sensor systems
  • Surface plasmon resonant
  • Sensor network

Published Papers (16 papers)

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Research

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11 pages, 3115 KiB  
Article
Experimental Study on Deformation Monitoring of Bored Pile Based on BOTDR
by Lei Gao, Chuan Han, Zhongquan Xu, Yingjie Jin and Jianqiang Yan
Appl. Sci. 2019, 9(12), 2435; https://0-doi-org.brum.beds.ac.uk/10.3390/app9122435 - 14 Jun 2019
Cited by 29 | Viewed by 2624
Abstract
In order to study the deformation of bored pile, it is necessary to monitor the strain of the pile. The distributed optical fiber sensing technology realizes the integration of sensing and transmission, which is incomparable with traditional point monitoring method. In this paper, [...] Read more.
In order to study the deformation of bored pile, it is necessary to monitor the strain of the pile. The distributed optical fiber sensing technology realizes the integration of sensing and transmission, which is incomparable with traditional point monitoring method. In this paper, the Brillouin optical time domain reflectometer (BOTDR) distributed optical fiber sensing technology is used to monitor the deformation of the bored pile. The raw data monitored by BOTDR is processed by the wavelet basis function, that can perform noise removal processing. Three different methods of noise removal are chosen. Through the processing, the db5 wavelet is used to decompose the deformation data of bored pile monitored by BOTDR into two layers. The decomposed high-frequency signal is denoised by the Stein-based unbiased risk threshold, rigrsure. The decomposed data is smoothed by the translational mean method, and the final data after denoising and smoothing processing is real and reliable. The results of this study will provide data support for the deformation characteristics of bored pile, and also show the advantages of distributed optical fiber sensing technology. Full article
(This article belongs to the Special Issue Recent Progress in Fiber Optic Sensors: Bringing Light to Measurement)
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11 pages, 4700 KiB  
Article
High Temperature (Up to 950 °C) Sensor Based on Micro Taper In-Line Fiber Mach–Zehnder Interferometer
by Yun-Cheng Liao, Bin Liu, Juan Liu, Sheng-Peng Wan, Xing-Dao He, Jinhui Yuan, Xinyu Fan and Qiang Wu
Appl. Sci. 2019, 9(12), 2394; https://0-doi-org.brum.beds.ac.uk/10.3390/app9122394 - 12 Jun 2019
Cited by 15 | Viewed by 3149
Abstract
A high temperature (up to 950 °C) sensor was proposed and demonstrated based on a micro taper in-line fiber Mach–Zehnder interferometer (MZI) structure. The fiber MZI structure comprises a single mode fiber (SMF) with two micro tapers along its longitudinal direction. An annealing [...] Read more.
A high temperature (up to 950 °C) sensor was proposed and demonstrated based on a micro taper in-line fiber Mach–Zehnder interferometer (MZI) structure. The fiber MZI structure comprises a single mode fiber (SMF) with two micro tapers along its longitudinal direction. An annealing at 1000 °C was applied to the fiber sensor to stabilize the temperature measurement. The experimental results showed that the sensitivity was 0.114 nm/°C and 0.116 nm/°C for the heating and cooling cycles, respectively, and, after two days, the sensor still had a sensitivity of 0.11 nm/°C, showing a good stability of the sensor. A probe-type fiber MZI was designed by cutting the sandwiched SMF, which has good linear temperature responses of 0.113 nm/°C over a large temperature range from 89 to 950 °C. The probe-type fiber MZI temperature sensor was independent to the surrounding refractive index (RI) and immune to strain. The developed sensor has a wide application prospect in the fields of high temperature hot gas flow, as well as oil and gas field development. Full article
(This article belongs to the Special Issue Recent Progress in Fiber Optic Sensors: Bringing Light to Measurement)
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18 pages, 7261 KiB  
Article
Framework and Application of a Big Data Monitoring System for Mining with a Pillar-Free Self-Forming Roadway
by Zhigang Tao, Xiaohui Zheng, Chun Zhu, Haijiang Zhang and Xiulian Zhang
Appl. Sci. 2019, 9(10), 2111; https://0-doi-org.brum.beds.ac.uk/10.3390/app9102111 - 23 May 2019
Cited by 5 | Viewed by 2654
Abstract
The construction of a self-formed roadway without coal pillars is a new mining technology based on short-arm beam formation through roof cutting. With it, mining, tunneling and retaining roadway construction can be accomplished in a ‘three-in-one’ process that removes the need to dig [...] Read more.
The construction of a self-formed roadway without coal pillars is a new mining technology based on short-arm beam formation through roof cutting. With it, mining, tunneling and retaining roadway construction can be accomplished in a ‘three-in-one’ process that removes the need to dig in advance at the working face and to leave behind coal pillars. In order to realize real-time monitoring and warnings regarding rock pressure during this process, a big data monitoring system was developed based on quasi-distributed fiber Bragg grating (FBG) sensing technology and cloud technology. Firstly, real-time monitoring data on the stress and strain of the underground surrounding rock-support system are obtained by FBG sensor and transmitted to the main computer of the above-ground monitoring and early warning system by using an underground industrial ring network. These data are then sent to a big data remote online real-time monitoring system. Through the deployment of a cloud server, authorized users can observe changes in force and movement in the rock surrounding the supporting system during coal mining and roadway formation from anywhere and at any time. The successful application of the system in the S1201-II working face of the Ning Tiaota Mine shows that this remote real-time monitoring system can enable timely and accurate field data acquisition, feedback real-time production information and achieve good monitoring performance. This study thus provides a scientific basis for ensuring safe mining with the coal pillar-free self-forming roadway method. Full article
(This article belongs to the Special Issue Recent Progress in Fiber Optic Sensors: Bringing Light to Measurement)
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9 pages, 1666 KiB  
Article
Hybrid Grating in Reduced-Diameter Fiber for Temperature-Calibrated High-Sensitivity Refractive Index Sensing
by Biqiang Jiang, Zhen Hao, Dingyi Feng, Kaiming Zhou, Lin Zhang and Jianlin Zhao
Appl. Sci. 2019, 9(9), 1923; https://0-doi-org.brum.beds.ac.uk/10.3390/app9091923 - 10 May 2019
Cited by 6 | Viewed by 2532
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Recent Progress in Fiber Optic Sensors: Bringing Light to Measurement)
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10 pages, 2780 KiB  
Article
Reflective Fiber Surface Plasmon Resonance Sensor for High-Sensitive Mercury Ion Detection
by Zhenlin Chen, Kunlin Han and Ya-Nan Zhang
Appl. Sci. 2019, 9(7), 1480; https://0-doi-org.brum.beds.ac.uk/10.3390/app9071480 - 09 Apr 2019
Cited by 29 | Viewed by 3776
Abstract
This paper proposes a reflective fiber mercury ion sensor based on the surface plasmon resonance (SPR) principle and chitosan (CS)/polyacrylic acid (PAA) multilayer sensitive film. By optimizing the coating parameters of the gold film, the refractive index (RI) sensitivity of the reflective SPR [...] Read more.
This paper proposes a reflective fiber mercury ion sensor based on the surface plasmon resonance (SPR) principle and chitosan (CS)/polyacrylic acid (PAA) multilayer sensitive film. By optimizing the coating parameters of the gold film, the refractive index (RI) sensitivity of the reflective SPR sensor is demonstrated to be 2110.33 nm/RIU. Then, a multi-layer CS/PAA film is fixed on the surface of the gold film as a mercury ion sensitive film to form a reflective SPR fiber mercury ion sensor. Experimental results demonstrate that the sensor can be used to detect different concentrations of mercury ions with a high sensitivity of 0.5586 nm/μM and good specificity and repeatability. Therefore, the reflective SPR fiber mercury ion sensor shows great promise for future applications of environmental monitoring and drinking water safety. Full article
(This article belongs to the Special Issue Recent Progress in Fiber Optic Sensors: Bringing Light to Measurement)
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15 pages, 5853 KiB  
Article
Wing Load and Angle of Attack Identification by Integrating Optical Fiber Sensing and Neural Network Approach in Wind Tunnel Test
by Daichi Wada and Masato Tamayama
Appl. Sci. 2019, 9(7), 1461; https://0-doi-org.brum.beds.ac.uk/10.3390/app9071461 - 08 Apr 2019
Cited by 9 | Viewed by 3226
Abstract
The load and angle of attack (AoA) for wing structures are critical parameters to be monitored for efficient operation of an aircraft. This study presents wing load and AoA identification techniques by integrating an optical fiber sensing technique and a neural network approach. [...] Read more.
The load and angle of attack (AoA) for wing structures are critical parameters to be monitored for efficient operation of an aircraft. This study presents wing load and AoA identification techniques by integrating an optical fiber sensing technique and a neural network approach. We developed a 3.6-m semi-spanned wing model with eight flaps and bonded two optical fibers with 30 fiber Bragg gratings (FBGs) each along the main and aft spars. Using this model in a wind tunnel test, we demonstrate load and AoA identification through a neural network approach. We input the FBG data and the eight flap angles to a neural network and output estimated load distributions on the eight wing segments. Thereafter, we identify the AoA by using the estimated load distributions and the flap angles through another neural network. This multi-neural-network process requires only the FBG and flap angle data to be measured. We successfully identified the load distributions with an error range of −1.5–1.4 N and a standard deviation of 0.57 N. The AoA was also successfully identified with error ranges of −1.03–0.46° and a standard deviation of 0.38°. Full article
(This article belongs to the Special Issue Recent Progress in Fiber Optic Sensors: Bringing Light to Measurement)
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11 pages, 3080 KiB  
Article
Optical Properties of Buffers and Cell Culture Media for Optofluidic and Sensing Applications
by Van Thuy Hoang, Grzegorz Stępniewski, Karolina H. Czarnecka, Rafał Kasztelanic, Van Cao Long, Khoa Dinh Xuan, Liyang Shao, Mateusz Śmietana and Ryszard Buczyński
Appl. Sci. 2019, 9(6), 1145; https://0-doi-org.brum.beds.ac.uk/10.3390/app9061145 - 18 Mar 2019
Cited by 45 | Viewed by 6266
Abstract
Interactions between light and various cells in cultures, such as bacteria or mammalian cells, are widely applied for optical sensors and optofluidic systems. These microorganisms need to be kept in proper aqueous media, referred to as buffers or cell culture media, that are [...] Read more.
Interactions between light and various cells in cultures, such as bacteria or mammalian cells, are widely applied for optical sensors and optofluidic systems. These microorganisms need to be kept in proper aqueous media, referred to as buffers or cell culture media, that are required, respectively, for stable storage or delivering biochemical nutrients for their growth. When experiments or numerical analyses on optical devices are performed, the properties of these media are usually considered to be similar to those of pure water, with negligible influence of biochemical compounds on the medium’s optical properties. In this work, we investigated the transmission, material dispersion, and scattering properties of selected and widely used buffers and cell culture media. We show that the optical properties of these media may significantly vary from those of water. Well-defined properties of buffers and cell culture media are essential for proper design of various optical sensing or future optofluidic systems dealing with biological structures. Full article
(This article belongs to the Special Issue Recent Progress in Fiber Optic Sensors: Bringing Light to Measurement)
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11 pages, 2479 KiB  
Article
Influence of Initial Phase Modulation on the Sensitivity of the Optical Fiber Sagnac Acoustic Emission Sensor
by Zhuming Cheng, Jie Zeng, Dakai Liang, Chen Chang and Bing Wang
Appl. Sci. 2019, 9(5), 1018; https://0-doi-org.brum.beds.ac.uk/10.3390/app9051018 - 12 Mar 2019
Cited by 4 | Viewed by 2790
Abstract
Improving the phase sensitivity of the optical fiber Sagnac sensor is very important for accurately detecting weak signals of acoustic emission. Theoretical analysis shows that the initial phase of the sensor is π under ideal conditions, and the maximum phase sensitivity is obtained [...] Read more.
Improving the phase sensitivity of the optical fiber Sagnac sensor is very important for accurately detecting weak signals of acoustic emission. Theoretical analysis shows that the initial phase of the sensor is π under ideal conditions, and the maximum phase sensitivity is obtained when the bias phase is π/2. In this work, an experimental system was built with an aluminum alloy plate as the experimental object. The initial phase of the sensor was modulated by a Y-branch waveguide, and the fitting curve of the experimental data was in good agreement with the curve of the numerical simulation. Moreover, our experiments show there was a single value for the bias phase of π/2, which significantly deviated from the theoretical value. The results show that the greatest phase sensitivity of the sensor not only could be increased by nearly nine times through modulating the initial phase, but also could suppress the harmonic interferences in the sensing system. This study can provide a useful reference for improving the phase sensitivity of the optical fiber Sagnac AE sensor in practical applications. Full article
(This article belongs to the Special Issue Recent Progress in Fiber Optic Sensors: Bringing Light to Measurement)
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14 pages, 2784 KiB  
Article
Fiber Optic Sensing for Geomechanical Monitoring: (2)- Distributed Strain Measurements at a Pumping Test and Geomechanical Modeling of Deformation of Reservoir Rocks
by Xinglin Lei, Ziqiu Xue and Tsutomu Hashimoto
Appl. Sci. 2019, 9(3), 417; https://0-doi-org.brum.beds.ac.uk/10.3390/app9030417 - 26 Jan 2019
Cited by 21 | Viewed by 4090
Abstract
In this study distributed fiber optic sensing has been used to measure strain along a vertical well of a depth of 300 m during a pumping test. The observed strain data has been used in geomechanical simulation, in which a combined analytical and [...] Read more.
In this study distributed fiber optic sensing has been used to measure strain along a vertical well of a depth of 300 m during a pumping test. The observed strain data has been used in geomechanical simulation, in which a combined analytical and numerical approach was applied in providing scaled-up formation properties. The outcomes of the field test have demonstrated the practical use of distributed fiber optic strain sensing for monitoring reservoir formation responses at different regions of sandstone–mudstone alternations along a continuous trajectory. It also demonstrated that sensitive and scaled rock properties, including the equivalent permeability and pore compressibility, can be well constrained by the combined use of water head and distributed strain data. In comparison with the conventional methods, fiber optic strain monitoring enables a lower number of short-term tests to be designed to calibrate the parameters used to model the rock properties. The obtained parameters can be directly used in long-term geomechanical simulation of deformation of reservoir rocks due to fluid injection or production at the CO2 storage and oil and gas fields. Full article
(This article belongs to the Special Issue Recent Progress in Fiber Optic Sensors: Bringing Light to Measurement)
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15 pages, 4607 KiB  
Article
Characteristic Analysis and Experiment of Adaptive Fiber Optic Current Sensor Technology
by Yansong Li, Weiwei Zhang, Xinying Liu and Jun Liu
Appl. Sci. 2019, 9(2), 333; https://0-doi-org.brum.beds.ac.uk/10.3390/app9020333 - 18 Jan 2019
Cited by 16 | Viewed by 4139
Abstract
The straight-through magneto-optical glass current sensor has desirable temperature properties, but it is vulnerable to magnetic interference. In contrast, a polarization-type fiber optic current sensor has poor temperature performance, but the magnetic anti-interference characteristic is very good. Aiming at the problem that the [...] Read more.
The straight-through magneto-optical glass current sensor has desirable temperature properties, but it is vulnerable to magnetic interference. In contrast, a polarization-type fiber optic current sensor has poor temperature performance, but the magnetic anti-interference characteristic is very good. Aiming at the problem that the accuracy of a fiber optic current sensor is susceptible to external disturbances and temperature fluctuations, we present an adaptive technology of a fiber optic current sensor that uses the magneto-optical output signal to correct the fiber output signal. The working principle of the improved method is introduced in this paper. The structure of the specific optical system and the signal processing system are presented. Temperature fluctuation and magnetic change detection units are included in the design in order to provide signal selection under different environmental fluctuations, thus stabilizing the output current data. The signal processing system was proved to be effective by building an experimental platform. Full article
(This article belongs to the Special Issue Recent Progress in Fiber Optic Sensors: Bringing Light to Measurement)
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19 pages, 6532 KiB  
Article
Denoising of the Fiber Bragg Grating Deformation Spectrum Signal Using Variational Mode Decomposition Combined with Wavelet Thresholding
by Weifang Zhang, Meng Zhang, Yan Zhao, Bo Jin and Wei Dai
Appl. Sci. 2019, 9(1), 180; https://0-doi-org.brum.beds.ac.uk/10.3390/app9010180 - 06 Jan 2019
Cited by 13 | Viewed by 3035
Abstract
Damage detection using an FBG sensor is a critical process for an assessment of any inspection technology classified as structural health monitoring (SHM). FBG signals containing noise in experiments are developed to detect flaws. In this paper, we propose a novel signal denoising [...] Read more.
Damage detection using an FBG sensor is a critical process for an assessment of any inspection technology classified as structural health monitoring (SHM). FBG signals containing noise in experiments are developed to detect flaws. In this paper, we propose a novel signal denoising method that combines variational mode decomposition (VMD) and changed thresholding wavelets to denoise experimental and mixed signals. VMD is a recently introduced adaptive signal decomposition algorithm. Compared with traditional empirical mode decomposition (EMD), and it is well founded theoretically and more robust to noise samples. First, input signals were broken down into a given number of K band-limited intrinsic mode functions (BLIMFs) by VMD. For the purpose of avoiding the impact of overbinning or underbinning on VMD denoising, the mixed signals, which were obtained by adding different signal/noise ratio (SNR) noises to the experimental signals, were designed to select the best decomposition number K and data-fidelity constraint parameter α. After that, the realistic experimental signals were processed using four denoising algorithms to evaluate denoising performance. The results show that, upon adding additional noisy signals and realistic signals, the proposed algorithm delivers excellent performance over the EMD-based denoising method and discrete wavelet transform filtering. Full article
(This article belongs to the Special Issue Recent Progress in Fiber Optic Sensors: Bringing Light to Measurement)
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17 pages, 24586 KiB  
Article
Use of Fiber-Optic Sensors for the Detection of the Rail Vehicles and Monitoring of the Rock Mass Dynamic Response Due to Railway Rolling Stock for the Civil Engineering Needs
by Jan Nedoma, Martin Stolarik, Marcel Fajkus, Miroslav Pinka and Stanislav Hejduk
Appl. Sci. 2019, 9(1), 134; https://0-doi-org.brum.beds.ac.uk/10.3390/app9010134 - 02 Jan 2019
Cited by 16 | Viewed by 3907
Abstract
The paper describes the original results of a comparative study of the standard seismic station vs. a novel interferometric sensor for civil engineering needs. The presented results showed that to implement seismic measurements using standard seismic stations, a method using a fiber optic [...] Read more.
The paper describes the original results of a comparative study of the standard seismic station vs. a novel interferometric sensor for civil engineering needs. The presented results showed that to implement seismic measurements using standard seismic stations, a method using a fiber optic interferometer may serve as an alternative. We presented time records and the frequency spectra obtained from experimental measurements of the dynamic response of the upper rock mass beneath passing tram vehicles (a total of 769 passes) over a period of five months of practical measurements under various climatic conditions. The fiber-optic sensor detected all phenomena at a 100% rate, and the recorded results were compared to the results from a standard seismic station. Both sets of results were recorded simultaneously and agreed significantly, especially in terms of frequency. With regard to time, all tram vehicle axles were detected in individual time records. With regard to frequency, the results detected in the bandwidth generally correlated to rail transport for individual types of tram vehicles. Full article
(This article belongs to the Special Issue Recent Progress in Fiber Optic Sensors: Bringing Light to Measurement)
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11 pages, 3007 KiB  
Communication
Game Theory in Molecular Nanosensing System for Rapid Detection of Hg2+ in Aqueous Solutions
by Nan Fang Nie, Xin Xing Zhang, Chu Shan Fang, Qiu Yan Zhu, Jiao Yang Lu, Fu Rui Zhang, Qing Feng Yao, Wei Tao Huang, Xue Zhi Ding and Li Qiu Xia
Appl. Sci. 2018, 8(12), 2530; https://0-doi-org.brum.beds.ac.uk/10.3390/app8122530 - 07 Dec 2018
Cited by 5 | Viewed by 2671
Abstract
Game theory—the scientific study of interactive, rational decision making—describes the interaction of two or more players from macroscopic organisms to microscopic cellular and subcellular levels. Life based on molecules is the highest and most complex expression of molecular interactions. However, using simple molecules [...] Read more.
Game theory—the scientific study of interactive, rational decision making—describes the interaction of two or more players from macroscopic organisms to microscopic cellular and subcellular levels. Life based on molecules is the highest and most complex expression of molecular interactions. However, using simple molecules to expand game theory for molecular decision-making remains challenging. Herein, we demonstrate a proof-of-concept molecular game-theoretical system (molecular prisoner’s dilemma) that relies on formation of the thymine–Hg2+–thymine hairpin structure specifically induced by Hg2+ and fluorescence quenching and molecular adsorption capacities of cobalt oxyhydroxide (CoOOH) nanosheets, resulting in fluorescence intensity and distribution change of polythymine oligonucleotide 33-repeat thymines (T33). The “bait” molecule, T33, interacted with two molecular players, CoOOH and Hg2+, in different states (absence = silence and presence = betrayal), regarded as strategies. We created conflicts (sharing or self-interest) of fluorescence distribution of T33, quantifiable in a 2 × 2 payoff matrix. In addition, the molecular game-theoretical-system based on T33 and CoOOH was used for sensing Hg2+ over the range of 20 to 600 nM with the detection limit of 7.94 nM (3σ) and for determination of Hg2+ in pond water. Inspired by the proof-of-concept for molecular game theory, various molecular decision-making systems could be developed, which would help promote molecular information processing and generating novel molecular intelligent decision systems for environmental monitoring and molecular diagnosis and therapy. Full article
(This article belongs to the Special Issue Recent Progress in Fiber Optic Sensors: Bringing Light to Measurement)
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Review

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18 pages, 3972 KiB  
Review
Reviews on Corrugated Diaphragms in Miniature Fiber-Optic Pressure Sensors
by Honglin Li, Hui Deng, Guangqi Zheng, Mingguang Shan, Zhi Zhong and Bin Liu
Appl. Sci. 2019, 9(11), 2241; https://0-doi-org.brum.beds.ac.uk/10.3390/app9112241 - 30 May 2019
Cited by 11 | Viewed by 5267
Abstract
Corrugated diaphragms (CDs) have been widely used in many fields because of their higher pressure sensitivity and wider linear range compared to flat diaphragms (FDs) in the same circumstances. Especially in the application of miniature fiber-optic pressure sensors, the introduction of the corrugated [...] Read more.
Corrugated diaphragms (CDs) have been widely used in many fields because of their higher pressure sensitivity and wider linear range compared to flat diaphragms (FDs) in the same circumstances. Especially in the application of miniature fiber-optic pressure sensors, the introduction of the corrugated structure gives the sensor high sensitivity, large dynamic range, good linearity, small hysteresis, good stability, and so on. Research on CD-based miniature fiber-optic pressure sensors has gradually attracted more attention in recent years. In this paper, the principles of operation of a miniature fiber-optic pressure sensor are briefly introduced, then the mechanical properties of FD and CD, as well as their influences on the performance of the sensor, are analyzed in detail. The application status of CDs in miniature fiber-optic pressure sensors is reviewed, and our conclusions and the prospects for the application of CDs in miniature fiber-optic pressure sensors are given finally. Full article
(This article belongs to the Special Issue Recent Progress in Fiber Optic Sensors: Bringing Light to Measurement)
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22 pages, 4394 KiB  
Review
Recent Advances in Plasmonic Sensor-Based Fiber Optic Probes for Biological Applications
by M. S. Aruna Gandhi, Suoda Chu, K. Senthilnathan, P. Ramesh Babu, K. Nakkeeran and Qian Li
Appl. Sci. 2019, 9(5), 949; https://0-doi-org.brum.beds.ac.uk/10.3390/app9050949 - 06 Mar 2019
Cited by 109 | Viewed by 12971
Abstract
The survey focuses on the most significant contributions in the field of fiber optic plasmonic sensors (FOPS) in recent years. FOPSs are plasmonic sensor-based fiber optic probes that use an optical field to measure the biological agents. Owing to their high sensitivity, high [...] Read more.
The survey focuses on the most significant contributions in the field of fiber optic plasmonic sensors (FOPS) in recent years. FOPSs are plasmonic sensor-based fiber optic probes that use an optical field to measure the biological agents. Owing to their high sensitivity, high resolution, and low cost, FOPS turn out to be potential alternatives to conventional biological fiber optic sensors. FOPS use optical transduction mechanisms to enhance sensitivity and resolution. The optical transduction mechanisms of FOPS with different geometrical structures and the photonic properties of the geometries are discussed in detail. The studies of optical properties with a combination of suitable materials for testing the biosamples allow for diagnosing diseases in the medical field. Full article
(This article belongs to the Special Issue Recent Progress in Fiber Optic Sensors: Bringing Light to Measurement)
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Other

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7 pages, 2275 KiB  
Letter
Ultra-Small Fiber Bragg Grating Accelerometer
by Kuo Li, Guoyong Liu, Yuqing Li, Jun Yang and Wenlong Ma
Appl. Sci. 2019, 9(13), 2707; https://0-doi-org.brum.beds.ac.uk/10.3390/app9132707 - 03 Jul 2019
Cited by 10 | Viewed by 2204
Abstract
Reducing the size of an accelerometer overcomes the tradeoff between its sensitivity and resonant frequency, and the theoretical relationships are analyzed. A fiber Bragg grating (FBG) accelerometer with the shortest vibration arm, 7 mm, among FBG accelerometers using the optical fiber to hold [...] Read more.
Reducing the size of an accelerometer overcomes the tradeoff between its sensitivity and resonant frequency, and the theoretical relationships are analyzed. A fiber Bragg grating (FBG) accelerometer with the shortest vibration arm, 7 mm, among FBG accelerometers using the optical fiber to hold its inertial object is demonstrated here. The inertial object was 4.41 g. The experimental crest-to-trough sensitivity and resonant frequency, 244 pm/g and 90 Hz, disagree with the theoretical values, 633 pm/g and 67 Hz, perhaps due to the friction between the inertial object and shell. In order to find the theoretical values, a method to find the pre-stretch of the FBG is also presented here, based on the stretch of the FBG at equilibrium and the mass of the inertial object. The FFT program, experimental data and theoretical calculations are presented in detail in the Supplementary Material. Full article
(This article belongs to the Special Issue Recent Progress in Fiber Optic Sensors: Bringing Light to Measurement)
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