{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,10]],"date-time":"2026-04-10T16:36:18Z","timestamp":1775838978633,"version":"3.50.1"},"reference-count":99,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2023,2,15]],"date-time":"2023-02-15T00:00:00Z","timestamp":1676419200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"THE NATIONAL KEY RESEARCH AND DEVELOPMENT PROGRAM OF CHINA","award":["2022YFB3205300"],"award-info":[{"award-number":["2022YFB3205300"]}]},{"name":"THE NATIONAL KEY RESEARCH AND DEVELOPMENT PROGRAM OF CHINA","award":["42276194"],"award-info":[{"award-number":["42276194"]}]},{"name":"THE NATIONAL NATURAL SCIENCE FOUNDATION OF CHINA","award":["2022YFB3205300"],"award-info":[{"award-number":["2022YFB3205300"]}]},{"name":"THE NATIONAL NATURAL SCIENCE FOUNDATION OF CHINA","award":["42276194"],"award-info":[{"award-number":["42276194"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This paper presents a systematic review of the research available on salinity optic fiber sensors (OFSs) for seawater based on the refractive index (RI) measurement principle for the actual measurement demand of seawater salinity in marine environmental monitoring, the definition of seawater salinity and the correspondence between the seawater RI and salinity. To further investigate the progress of in situ measurements of absolute salinity by OFSs, the sensing mechanisms, research progress and measurement performance indices of various existing fiber optic salinity sensors are summarized. According to the Thermodynamic Equation of Seawater-2010 (TEOS-10), absolute salinity is recommended for sensor calibration and measurement. Comprehensive domestic and international research progress shows that fiber-optic RI sensors are ideal for real-time, in situ measurement of the absolute salinity of seawater and have excellent potential for application in long-term in situ measurements in the deep ocean. Finally, based on marine environmental monitoring applications, a development plan and the technical requirements of salinity OFSs are proposed to provide references for researchers engaged in related industries.<\/jats:p>","DOI":"10.3390\/s23042187","type":"journal-article","created":{"date-parts":[[2023,2,15]],"date-time":"2023-02-15T04:47:24Z","timestamp":1676436444000},"page":"2187","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":55,"title":["Review of Seawater Fiber Optic Salinity Sensors Based on the Refractive Index Detection Principle"],"prefix":"10.3390","volume":"23","author":[{"given":"Gaochao","family":"Li","sequence":"first","affiliation":[{"name":"State Key Laboratory of Transducer Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China"},{"name":"College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9777-0241","authenticated-orcid":false,"given":"Yongjie","family":"Wang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Transducer Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China"},{"name":"College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China"}]},{"given":"Ancun","family":"Shi","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Transducer Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China"}]},{"given":"Yuanhui","family":"Liu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Transducer Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China"}]},{"given":"Fang","family":"Li","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Transducer Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China"},{"name":"College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China"}]}],"member":"1968","published-online":{"date-parts":[[2023,2,15]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"17029","DOI":"10.1007\/s11356-021-12741-z","article-title":"A Review: Saltwater Intrusion in North Africa\u2019s Coastal Areas-Current State and Future Challenges","volume":"28","author":"Agoubi","year":"2021","journal-title":"Environ. 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