scholarly journals Cost-effective optical coherence tomography spectrometer based on a tilted fiber Bragg grating

Author(s):  
Stefan Remund ◽  
Anke Bossen ◽  
Xianfeng Chen ◽  
Ling Wang ◽  
Adedotun Adebayo ◽  
...  
Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3639
Author(s):  
Abdelfateh Kerrouche ◽  
Taoufik Najeh ◽  
Pablo Jaen-Sola

Railway infrastructure plays a major role in providing the most cost-effective way to transport freight and passengers. The increase in train speed, traffic growth, heavier axles, and harsh environments make railway assets susceptible to degradation and failure. Railway switches and crossings (S&C) are a key element in any railway network, providing flexible traffic for trains to switch between tracks (through or turnout direction). S&C systems have complex structures, with many components, such as crossing parts, frogs, switchblades, and point machines. Many technologies (e.g., electrical, mechanical, and electronic devices) are used to operate and control S&C. These S&C systems are subject to failures and malfunctions that can cause delays, traffic disruptions, and even deadly accidents. Suitable field-based monitoring techniques to deal with fault detection in railway S&C systems are sought after. Wear is the major cause of S&C system failures. A novel measuring method to monitor excessive wear on the frog, as part of S&C, based on fiber Bragg grating (FBG) optical fiber sensors, is discussed in this paper. The developed solution is based on FBG sensors measuring the strain profile of the frog of S&C to determine wear size. A numerical model of a 3D prototype was developed through the finite element method, to define loading testing conditions, as well as for comparison with experimental tests. The sensors were examined under periodic and controlled loading tests. Results of this pilot study, based on simulation and laboratory tests, have shown a correlation for the static load. It was shown that the results of the experimental and the numerical studies were in good agreement.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Thomas Kurmann ◽  
Siqing Yu ◽  
Pablo Márquez-Neila ◽  
Andreas Ebneter ◽  
Martin Zinkernagel ◽  
...  

Abstract In ophthalmology, retinal biological markers, or biomarkers, play a critical role in the management of chronic eye conditions and in the development of new therapeutics. While many imaging technologies used today can visualize these, Optical Coherence Tomography (OCT) is often the tool of choice due to its ability to image retinal structures in three dimensions at micrometer resolution. But with widespread use in clinical routine, and growing prevalence in chronic retinal conditions, the quantity of scans acquired worldwide is surpassing the capacity of retinal specialists to inspect these in meaningful ways. Instead, automated analysis of scans using machine learning algorithms provide a cost effective and reliable alternative to assist ophthalmologists in clinical routine and research. We present a machine learning method capable of consistently identifying a wide range of common retinal biomarkers from OCT scans. Our approach avoids the need for costly segmentation annotations and allows scans to be characterized by biomarker distributions. These can then be used to classify scans based on their underlying pathology in a device-independent way.


Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 770
Author(s):  
Konrad Markowski ◽  
Kacper Wojakowski ◽  
Ernest Pokropek ◽  
Michał Marzęcki

In this article, an extensive analysis of the performance of the fiber optics-based abrasion sensor that utilizes chirped fiber Bragg grating, is presented. For the response investigation during abrasion, a numerical analysis, based on the transfer matrix method and coupled mode theory, is provided. The influence of the SLED source spectral position in respect to the spectral position of the chirped fiber Bragg grating is evaluated together with the influence of the changes of the ambient temperature of the sensor. Experimental verification of the sensor’s performance is provided, together with the proposition of the packaging of the sensor. In the article, a simple, cost-effective and multiplexation-ready concept of the wear or abrasion sensor system is presented and discussed.


2014 ◽  
Author(s):  
Stefan Remund ◽  
Anke Bossen ◽  
Xianfeng Chen ◽  
Ling Wang ◽  
Lin Zhang ◽  
...  

2013 ◽  
Vol 64 (3) ◽  
Author(s):  
Liau Qian Yu ◽  
Asrul Izam Azmi ◽  
Siti Musliha Aishah Musa ◽  
Raja Kamarulzaman Raja Ibrahim

The development of Fiber Bragg Grating (FBG) sensing technique has improved significantly especially in the sensor head design and real-time data acquisition technique. This paper presents the development of a simple and cost effective packaging technique that further enhances the performances of the FBG sensor. The packaged FBG sensor overcomes the nonuniform heat distribution of a bare FBG that causes eccentric response of FBG spectrum. Therefore, the packaged FBG sensor could be operated for a localized area with high temperature differential. The packaging also compensates the unwanted strain effect from the surrounding which makes temperature measurement become more accurate. The experimental works have been successfully carried out to demonstrate the system operation and the packaging functionalities. The temperature sensitivity coefficient of the bare FBG sensor measured in experiment is 10.05 pm/°C, while the packaged fiber sensor is 10.09 pm/°C, which are expected from the design.


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