{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T22:10:32Z","timestamp":1760220632197,"version":"build-2065373602"},"reference-count":27,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2012,9,12]],"date-time":"2012-09-12T00:00:00Z","timestamp":1347408000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Fiber-optic interferometric sensors based on graded-index multimode fibers have very high refractive-index sensitivity, as we previously demonstrated. In this paper, spatial-frequency multiplexing of this type of fiber-optic refractive index sensors is investigated. It is estimated that multiplexing of more than 10 such sensors is possible. In the multiplexing scheme, one of the sensors is used to investigate the refractive index and temperature responses. The fast Fourier transform (FFT) of the combined reflective spectra is analyzed. The intensity of the FFT spectra is linearly related with the refractive index and is not sensitive to the temperature.<\/jats:p>","DOI":"10.3390\/s120912377","type":"journal-article","created":{"date-parts":[[2012,9,12]],"date-time":"2012-09-12T12:11:41Z","timestamp":1347451901000},"page":"12377-12385","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":17,"title":["Spatial Frequency Multiplexing of Fiber-Optic Interferometric Refractive Index Sensors Based on Graded-Index Multimode Fibers"],"prefix":"10.3390","volume":"12","author":[{"given":"Li","family":"Liu","sequence":"first","affiliation":[{"name":"Key Lab of Optical Fiber Sensing & Communications (Education Ministry of China), University of Electronic Science & Technology of China, Chengdu, Sichuan 611731, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuan","family":"Gong","sequence":"additional","affiliation":[{"name":"Key Lab of Optical Fiber Sensing & Communications (Education Ministry of China), University of Electronic Science & Technology of China, Chengdu, Sichuan 611731, China"},{"name":"State Key Laboratory of Transient Optics and Photonics, Xi\u2019an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi\u2019an, Shaanxi 710119, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yu","family":"Wu","sequence":"additional","affiliation":[{"name":"Key Lab of Optical Fiber Sensing & Communications (Education Ministry of China), University of Electronic Science & Technology of China, Chengdu, Sichuan 611731, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tian","family":"Zhao","sequence":"additional","affiliation":[{"name":"Key Lab of Optical Fiber Sensing & Communications (Education Ministry of China), University of Electronic Science & Technology of China, Chengdu, Sichuan 611731, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hui-Juan","family":"Wu","sequence":"additional","affiliation":[{"name":"Key Lab of Optical Fiber Sensing & Communications (Education Ministry of China), University of Electronic Science & Technology of China, Chengdu, Sichuan 611731, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yun-Jiang","family":"Rao","sequence":"additional","affiliation":[{"name":"Key Lab of Optical Fiber Sensing & Communications (Education Ministry of China), University of Electronic Science & Technology of China, Chengdu, Sichuan 611731, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2012,9,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"141","DOI":"10.1364\/OE.18.000141","article-title":"Cross-talk free and ultra-compact fiber optic sensor for simultaneous measurement of temperature and refractive index","volume":"18","author":"Choi","year":"2010","journal-title":"Opt. 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