{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,28]],"date-time":"2026-03-28T12:29:45Z","timestamp":1774700985856,"version":"3.50.1"},"reference-count":30,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2023,5,15]],"date-time":"2023-05-15T00:00:00Z","timestamp":1684108800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Shandong Joint Fund Project of the National Natural Science Foundation of China (NSFC)","award":["U2006216"],"award-info":[{"award-number":["U2006216"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this study, a new temperature sensor with high sensitivity was achieved by four-layer Ge and B co-doped long-period fiber grating (LPFG) based on the mode coupling principle. By analyzing the mode conversion, the influence of the surrounding refractive index (SRI), the thickness and the refractive index of the film on the sensitivity of the sensor is studied. When 10 nm-thick titanium dioxide (TiO2) film is coated on the surface of the bare LPFG, the refractive index sensitivity of the sensor can be initially improved. Packaging PC452 UV-curable adhesive with a high-thermoluminescence coefficient for temperature sensitization can realize high-sensitivity temperature sensing and meet the requirements of ocean temperature detection. Finally, the effects of salt and protein attachment on the sensitivity are analyzed, which provides a reference for the subsequent application. The sensitivity of 3.8 nm\/\u00b0C in the range of 5\u201330 \u00b0C was achieved for this new sensor, and the resolution is about 0.00026 \u00b0C, which is over 20 times higher than ordinary temperature sensors. This new sensor meets the accuracy and range of general ocean temperature measurements and could be used in various marine monitoring and environmental protection applications.<\/jats:p>","DOI":"10.3390\/s23104768","type":"journal-article","created":{"date-parts":[[2023,5,16]],"date-time":"2023-05-16T02:27:04Z","timestamp":1684204024000},"page":"4768","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["High Sensitivity Temperature Sensing of Long-Period Fiber Grating for the Ocean"],"prefix":"10.3390","volume":"23","author":[{"given":"Jiayi","family":"Qu","sequence":"first","affiliation":[{"name":"Key Laboratory of Optoelectronics Information Technical Science, College of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6766-1263","authenticated-orcid":false,"given":"Hongxia","family":"Zhang","sequence":"additional","affiliation":[{"name":"Key Laboratory of Optoelectronics Information Technical Science, College of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China"}]},{"given":"Xinyu","family":"Shi","sequence":"additional","affiliation":[{"name":"Key Laboratory of Optoelectronics Information Technical Science, College of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China"},{"name":"Changchun National Extreme Precision Optics Co., Ltd., Changchun 130033, China"}]},{"given":"Chuanxi","family":"Li","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China"},{"name":"Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China"}]},{"given":"Dagong","family":"Jia","sequence":"additional","affiliation":[{"name":"Key Laboratory of Optoelectronics Information Technical Science, College of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China"}]},{"given":"Tiegen","family":"Liu","sequence":"additional","affiliation":[{"name":"Key Laboratory of Optoelectronics Information Technical Science, College of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China"}]},{"given":"Rongxin","family":"Su","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China"},{"name":"Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China"},{"name":"School of Marine Science and Technology, Tianjin University, Tianjin 300072, China"}]}],"member":"1968","published-online":{"date-parts":[[2023,5,15]]},"reference":[{"key":"ref_1","first-page":"060901","article-title":"Fiber Bragg grating sensors for monitoring of physical parameters: A comprehensive review","volume":"59","author":"Sahota","year":"2022","journal-title":"Opt. 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