This paper presents an overview of optical fiber sensor networks for remote sensing. Firstly, the state of the art of remote fiber sensor systems has been considered. We have summarized the great evolution of these systems in recent years; this progress confirms that fiber-optic remote sensing is a promising technology with a wide field of practical applications. Afterwards, the most representative remote fiber-optic sensor systems are briefly explained, discussing their schemes, challenges, pros and cons. Finally, a synopsis of the main factors to take into consideration in the design of a remote sensor system is gathered. ; This work was supported by the Spanish Government project TEC2010-20224-C02-01.
The fiber optic communications industry has undoubtedly revolutionized the information and telecommunications technology (ICT) offering higher-performance and more reliable telecommunication links with ever decreasing bandwidth cost [1]. Simultaneously with these developments, fiber optic sensor technology has been associated with the optoelectronic and fiber optic communications industry, and many of the components associated with these industries were often developed for fiber optic sensor applications [1]. Fiber optic sensors take advantages of the exceptional characteristics of the optical fiber, which include compactness and small size, fast response, high resolution and sensitivity, good stability and repeatability, multiplexing capabilities, remote sensing, high flexibility, low propagating loss, affordable fabrication costs, simultaneous sensing ability, and resistance to electromagnetic interference [2–5] [1]. As optics and fiber optics component prices have fallen and quality has improved, the competence of fiber optic sensors to displace traditional sensors has increased [1], [6]. Nowadays, sensors rule the world. Sensors play a fundamental role to control and predict different products and systems, from consumer electronics to industrial environments, passing by the weather monitoring and biological and healthcare diagnosis. Those applied to health care monitoring have many benefits: minimize the cost per analysis, easy access to remote places without laboratory facilities such as vulnerable populations, reduce the treatment time and optimize the resources of the government health care system, among others [7–10]. In Colombia, for example, some transmissible diseases most frequently affect the most vulnerable populations. Since the Ministry of Health and Social Protection in Colombia should guarantees free diagnosis and treatment, and many of Colombia's rural areas have no access to adequate health services due to geographical and demographic 26 Optical Fiber Sensors for measurements in Life Sciences characteristics, along with the difficulties caused by the armed conflict, and other situations of violence; the priority must be given to those rural areas. One of the main purposes of the Ministry of Health and Social Protection is to carry out continuous and systematic monitoring of the epidemiological behavior in transmissible diseases. This monitoring should be performed in accordance with processes established that allow the notification, collection, and data analysis. Thus generating valid and reliable timely information to guide prevention and control measures for those diseases [11]. However, achieving this purpose is very complicated if conventional methods used for the detection of the diseases fail to reach the population affected. Therefore, it is essential to adapt and improve the technology used to detect those diseases when it is required to collect information at the remote zones with difficulties in accessing health services. The optical fiber biosensensing technology exhibits a good promising future to solve the issues that the conventional diagnosis methods used present such as: long procedures, expensive equipment and reagents, specialized personnel, lack of portability, low sensitivities, and need of biomarkers. In addition to the sensitivity and selectivity, one of the fundamental characteristics that makes most biosensors so potential is the possibility of performing the analysis of the substance to be determined directly, i.e. without the need for a marker, and in real time. These two characteristics give biosensors the possibility to perform not only a qualitative and quantitative analysis, but also the possibility of evaluating the kinetics of the interaction (affinity constant, association and dissociation, among others) and, therefore, elucidate the fundamental mechanisms of such interaction. In this thesis it is studied a novel biosensing technology applied to immunoassays (detection of an antigen/antibody binding) based on the single-mode-multimode-single mode (SMS) fiber optic structure. This structure consists of optical fiber that relies on a multimode interferometry operating principle. Optical fiber SMS immunosensors here studied present several advantages: Optical Fiber Sensors 27 • The proposed structure has biosensing parameters comparable to those achieved by more complex structures like long period grating and surface plasmon resonances, which places this immunosensing device as a very promising option for biological and medical applications where high sensitivities, high selectivity and compact structures are required. • The sinusoidal spectrum of the SMS sensors proposed allows a sharp peak corresponding to the fundamental frequency to be observed. Consequently, it is possible to obtain a phase sensitive device by tracking the phase of this fundamental frequency as a function of the parameter to detect. FFT analysis technique is shown to have advantages since it could simplify the detection system making unnecessary the use of sophisticated optical interrogators. • The proposed structure and the bioassay performed is a label free assay, which implies that detection molecules are not labelled or modified. This means easier and lower cost procedures. The main results obtained using this concept of biosensors will be presented along this thesis as is described. First, Chapters 1 and 2, include an overview of the optical fiber sensors field, mainly focused on optical fiber biosensors. The sensors developed as a result of this thesis are presented as contributions in Chapters 3, 4, 5 and 6. These contributions were submitted to peer-reviewed top scientific journals and conferences. Finally, Chapter 7 presents and discusses a series of conclusions, current work, and future perspectives derived from this thesis. ; Doctorado
We use digitally enhanced heterodyne interferometry to measure the stability of optical fiber laser frequency references. Suppression of laser frequency noise by over four orders of magnitude is achieved using post processing time delay interferometry, allowing us to measure the mechanical stability for frequencies as low as 100 μHz. The performance of the digitally enhanced heterodyne interferometer platform used here is not practically limited by the dynamic range or bandwidth issues that can occur in feedback stabilization systems. This allows longer measurement times, better frequency discrimination, a reduction in spatially uncorrelated noise sources and an increase in interferometer sensitivity. An optical fiber frequency reference with the stability reported here, over a signal band of 20 mHz-1 Hz, has potential for use in demanding environments, such as space-based interferometry missions and optical flywheel applications. ; This work was supported under the Australian Government's Australian Space Research Programme.
We use digitally enhanced heterodyne interferometry to measure the stability of optical fiber laser frequency references. Suppression of laser frequency noise by over four orders of magnitude is achieved using post processing time delay interferometry, allowing us to measure the mechanical stability for frequencies as low as 100 μHz. The performance of the digitally enhanced heterodyne interferometer platform used here is not practically limited by the dynamic range or bandwidth issues that can occur in feedback stabilization systems. This allows longer measurement times, better frequency discrimination, a reduction in spatially uncorrelated noise sources and an increase in interferometer sensitivity. An optical fiber frequency reference with the stability reported here, over a signal band of 20 mHz-1 Hz, has potential for use in demanding environments, such as space-based interferometry missions and optical flywheel applications. ; This work was supported under the Australian Government's Australian Space Research Programme.
"(c) 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works." ; Polymer optical fiber (POF) is a growing technology in short distance telecommunication due to its flexibility, easy connectorization, and lower cost than the mostly deployed silica optical fiber technology. Microstructured POFs (mPOFs) have particular promising potential applications in the sensors and telecommunications field, and they could specially help to reduce losses in polymer fibers by using hollow-core fibers or reduce the modal dispersion by providing a large mode area endlessly single-mode. However, mPOFs are intrinsically more difficult to cut due to the cladding hole structure and it becomes necessary to have a high quality POF cleaver. In the well-known hot-blade cutting process, fiber and blade are heated, which requires electrical components and increases cost. A new method has recently been identified, allowing POF to be cut without the need for heating the blade and fiber, thus opening up the possibility of an electrically passive cleaver. In this letter, we describe the implementation and testing of a high quality cleaver based on a mechanical system formed by a constant force spring and a damper, which leads to the first reported electrical passive and portable cleaver. ; This work was supported in part by the Juan de la Cierva Program of the Spanish Government, in part by the National Project MINECO under Grant TEC2014-60378-C2-1-R MEMES, in part by the Regional GVA funded PROMETEO 2013/012 Project on Next Generation Microwave Photonic Technologies, and in part by the China Scholarship Council. ; D. Sáez-Rodriguez; Min, R.; Ortega Tamarit, B.; Nielsen, K.; Webb, D. (2016). Passive and Portable Polymer Optical Fiber Cleaver. IEEE ...
An ultrahigh temperature distributed sensor based on a Raman optical-time-domain-reflectometry (ROTDR) and two types of fibers: a standard multimode fiber and multimode gold-coated fiber are experimentally validated in this paper. A calibration technique has been implemented to correct the dynamic variation of the optical loss in the gold-coated fiber. Distributed temperature measurements up to 600º C have been carried out. ; This work was supported in part by the ENSA through TOMATIN project (cofounded by the Cantabria government) and in part by the Spanish Ministry of Economy and Competitiveness through the Projects TEC2013-47264-C2-1-R and TEC2016-76021-C2-2-R.
[EN] A plastic filament of poly (methyl methacrylate) (PMMA) was fabricated by extrusion. The mode confinement was simulated using numerical software. The idea is to study how the light intensity changes inside the plastic optical fiber (POF) when a bending in multiple directions is applied. The results obtained from the simulation were compared to the experimental observations. The non-circular shape of the POF allows sensing a rotation applied as well. The angle of rotation was obtained processing two images of the end facet of the fiber (one with the fiber in a reference position and one with the rotated fiber), using an intensity-based automatic image registration. The accuracy in the rotation calculation was of 0.01 degrees. ; FINESSE project, funded by the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Action grant agreement no 722509. Ministry of Economy and Competitiveness project DIMENSION TEC2017 and by the Generalitat Valenciana project PROMETEO 2017/017. ; Sartiano, D.; Geernaert, T.; Torres Roca, E.; Sales Maicas, S. (2020). Bend-Direction and Rotation Plastic Optical Fiber Sensor. Sensors. 20(18):1-9. https://doi.org/10.3390/s20185405 ; S ; 1 ; 9 ; 20 ; 18
A high-temperature distributed sensor system based on a Brillouin optical time-domain analyzer and a multimode gold-coated fiber is presented in this paper. Distributed measurements of temperatures up to 600 °C are demonstrated with a temperature accuracy of about 10 °C. The system shows a consistent response for repetitive measurements, even considering increasing or decreasing temperature changes. This is the first time to the best of our knowledge that a gold-coated fiber is used for high-temperature distributed measurements in a Brillouin-based system. The proposed solution via the gold-coated fiber allows a feasible deployment in field applications such as industrial scenarios. ; This work was supported in part by the Spanish Government through Projects under Grant TEC2013-47264-C2-1-R and Grant TEC2016-76021-C2-2-R and in part by a Parliament of Cantabria postdoc Grant.
Nanocoated D-shaped optical fibers have been proven as effective sensors. Here, we show that the full width at half minimum (FWHM) of lossy mode resonance can be reduced by optimizing the nanocoating width, thickness and refractive index. As a counterpart, several resonances are observed in the optical spectrum for specific conditions. These resonances are caused by multiple modes guided in the nanocoating. By optimizing the width of the coating and the imaginary part of its refractive index, it is possible to isolate one of these resonances, which allows one to reduce the full width at half minimum of the device and, hence, to increase the figure of merit. Moreover, it is even possible to avoid the need of a polarizer by designing a device where the resonance bands for TE and TM polarization are centered at the same wavelength. This is interesting for the development of optical filters and sensors with a high figure of merit. ; Spanish Ministry of Education and Science-FEDER (TEC2013-43679-R, TEC2016-78047- R); Government of Navarra Health Department (64/2015, 72/2015); Government of Navarra 2016/PI008.
Trabajo presentado a la 26th International Conference on Optical Fiber Sensors. Suiza, 2020 ; A fiber ring laser cavity configuration was used to analyze the effect of gamma-irradiation over the performance of different types of erbium doped fibers. Preliminary results validates this method to monitor gamma-radiation in real time. ; Financial support from the Spanish Comisión Interministerial de Ciencia y Tecnología within project TEC2016- 76021-C2-1-R and FEDER funds from the European Union are acknowledged. The reported investigations were performed in the frame of the COST Action MP 1401.
Potential niches for a power-over-fiber (PoF) technique can be found in hazardous areas that require controlling unauthorized access to risk areas and integration of multiple sensors, in scenarios avoiding electromagnetic interference, and the presence of ignition factors. This paper develops a PoF system that provides galvanic isolation between two ends of a fiber for remotely powering a proximity sensor as a proof of concept of the proposed technology. We analyze scalability issues for remotely powering multiple sensors in a specific application for the hazardous environment. The maximum number of remote sensors that can be optically powered and the limiting factors are also studied; considering different types of multimode optical fibers, span lengths, and wavelengths. We finally address the fiber mode field diameter effect as a factor that limits the maximum power to be injected into the fiber. This analysis shows the advantages of using step-index versus graded-index fibers. ; This work was supported in part by the Spanish Ministerio de Economía, Industria y Competitividad, Comunidad de Madrid and H2020 European Union Programme under Grants TEC2015-63826-C3-2-R and S2013/MIT-2790, in part by FSE, and in part by 5G PPP BlueSpace Project under Grant 762055. ; Publicado
We report the infrasonic performance of a fiber optic laser frequency reference with potential application to space-based gravitational wave detectors, such as the Laser Interferometer Space Antenna. We determine the optimum cross-over frequency between an optical frequency comb stabilized to a Rubidium atomic reference and two passive, all-fiber interferometers interrogated using digitally enhanced homodyne interferometery. By measuring the relative stability between the three independent optical frequency references, we find the optimum cross-over frequency to occur at 1.5 mHz, indicating that our passive fiber frequency reference is superior to the optical frequency comb at all higher frequencies. In addition, we find our fiber interferometers achieve a stability of 20 kHz/√Hz at 1.5 mHz, improving to a stability of 4 Hz/√Hz above 3 Hz. These results represent an independent characterization of digitally enhanced fiber references over long time scales and provide an estimate of thermal effects on these passively isolated systems, informing future reference architectures. ; This research is supported by an Australian Government Research Training Program (RTP) Scholarship.
Trabajo presentado a la 26th International Conference on Optical Fiber Sensors. Suiza, 2019 ; A discrete sensor based on a Sn0₂-FP (Fabry-Pérot) cavity is presented and characterized in real soil conditions. Results are compared, for the first time to our knowledge, with a commercial capacitive sensor and gravimetric measurements. ; The Spanish Government projects TEC 2016-76021-C2-1-R, TEC2016-78047-R, TEC2016-79367-C2-2-R, Innocampus and the Cost Action MP 1401, as well as to the AEI/FEDER Funds are acknowledged.
The international research community has been nurturing photonic technologies over the years, aiming to develop cost effective solutions for a number of applications. Optical fibers offer an efficient solution for sensing and communication fields. Fiber optic sensors present appealing characteristics that make them very attractive when compared with conventional electric sensors such as immunity to electromagnetic interferences, as well as unfavorable environments, small size, ability for multiplexing and remote sensing. Another important aspect when using optical fibers is the ability to simultaneously use them as sensors and communication channels. The primary motivation for this PhD work was the study and development of new structures based in photonic crystal fibers. The main idea was to take advantage of the know-how of our group in fiber-optic communications and photonic sensing, as well as the recent advances in the sensing area to develop new structures based on the platform of photonic crystal fibers. ; The work presented in this thesis was accomplished due to different financial supports, as well as co-work relationships inside of the university and outside during research times developed abroad. Due to the financial support obtained, thanks should be pay to: Spanish Government project TEC 2013-47264-C2-2-R; Innocampus and the INTERREG SUDOE Project "ECOAL-MGT-Ecological Management of Coal Waste Piles, SOE3/P2/P714"; As well as FEDER founds; Spanish Government project TEC 2016-76021-C2-1-R; Cost action MP1401; ; Programa de Doctorado en Tecnologías de las Comunicaciones, Bioingeniería y de las Energías Renovables (RD 99/2011) ; Bioingeniaritzako eta Komunikazioen eta Energia Berriztagarrien Teknologietako Doktoretza Programa (ED 99/2011)
