{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,7]],"date-time":"2025-11-07T13:23:27Z","timestamp":1762521807780,"version":"build-2065373602"},"reference-count":11,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2015,7,29]],"date-time":"2015-07-29T00:00:00Z","timestamp":1438128000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"publisher","award":["2010-0028509"],"award-info":[{"award-number":["2010-0028509"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Fiber Bragg grating sensors are placed in a fiber-optic Sagnac loop to combine the grating temperature sensors and the fiber-optic mandrel acoustic emission sensors in single optical circuit. A wavelength-scanning fiber-optic laser is used as a common light source for both sensors. A fiber-optic attenuator is placed at a specific position in the Sagnac loop in order to separate buried Bragg wavelengths from the Sagnac interferometer output. The Bragg wavelength shifts are measured with scanning band-pass filter demodulation and the mandrel output is analyzed by applying a fast Fourier transform to the interference signal. This hybrid-scheme could greatly reduce the size and the complexity of optical circuitry and signal processing unit, making it suitable for low cost multi-stress monitoring of large scale power systems.<\/jats:p>","DOI":"10.3390\/s150818579","type":"journal-article","created":{"date-parts":[[2015,7,29]],"date-time":"2015-07-29T10:25:31Z","timestamp":1438165531000},"page":"18579-18586","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Multi-Stress Monitoring System with Fiber-Optic Mandrels and Fiber Bragg Grating Sensors in a Sagnac Loop"],"prefix":"10.3390","volume":"15","author":[{"given":"Hyunjin","family":"Kim","sequence":"first","affiliation":[{"name":"Division of Electronics and Information Engineering, Chonbuk National University, Jeonju 561-756, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Umesh","family":"Sampath","sequence":"additional","affiliation":[{"name":"Division of Electronics and Information Engineering, Chonbuk National University, Jeonju 561-756, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Minho","family":"Song","sequence":"additional","affiliation":[{"name":"Division of Electronics and Information Engineering, Chonbuk National University, Jeonju 561-756, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2015,7,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Abiki, H., Afsharirad, H., Mohseni, A., Khoshkhati, F., Monsef, H., and Sahmsi, P. (2010, January 26\u201328). Effective on-line parameters for transformer monitoring and protection. Proceedings of the North American Power Symposium (NAPS), Arlington, TX, USA.","DOI":"10.1109\/NAPS.2010.5619954"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"12","DOI":"10.1109\/MEI.2002.1161455","article-title":"Review of condition assessment of power transformers in service","volume":"18","author":"Wang","year":"2002","journal-title":"Electr. Insulation Mag."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Gockenbach, E., and Borsi, H. (2008, January 21\u201324). Condition monitoring and diagnosis of power transformers. Proceedings of the Condition Monitoring and Diagnosis 2008, Beijing, China.","DOI":"10.1109\/CMD.2008.4580427"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1264","DOI":"10.1109\/JSEN.2008.926926","article-title":"Multipoint Fiber-Optic Hot-Spot Sensing Network Integrated into High Power Transformer for Continuous Monitoring","volume":"8","author":"Ribeiro","year":"2008","journal-title":"Sens. J."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"472","DOI":"10.1109\/TMTT.1982.1131089","article-title":"Optical fiber sensor technology","volume":"30","author":"Giallorenzi","year":"1982","journal-title":"Trans. Microw. Theory Tech."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1370","DOI":"10.1364\/OL.18.001370","article-title":"Multiplexed fiber Bragg grating strain-sensor system with a fiber Fabry-Perot wavelength filter","volume":"18","author":"Kersey","year":"1993","journal-title":"Opt. 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