{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T00:36:54Z","timestamp":1760229414270,"version":"build-2065373602"},"reference-count":27,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2022,6,14]],"date-time":"2022-06-14T00:00:00Z","timestamp":1655164800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"the National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["61975022","CQYC202005011","61825501"],"award-info":[{"award-number":["61975022","CQYC202005011","61825501"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"the Chongqing Talents","award":["61975022","CQYC202005011","61825501"],"award-info":[{"award-number":["61975022","CQYC202005011","61825501"]}]},{"DOI":"10.13039\/501100014219","name":"the National Science Fund for Distinguished Young Scholars","doi-asserted-by":"publisher","award":["61975022","CQYC202005011","61825501"],"award-info":[{"award-number":["61975022","CQYC202005011","61825501"]}],"id":[{"id":"10.13039\/501100014219","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Liquid-level sensors are required in modern industrial and medical fields. Optical liquid-level sensors can solve the safety problems of traditional electrical sensors, which have attracted extensive attention in both academia and industry. We propose a distributed liquid-level sensor based on optical frequency domain reflectometry and with no-core fiber. The sensing mechanism uses optical frequency domain reflectometry to capture the strong reflection of the evanescent field of the no-core fiber at the liquid\u2013air interface. The experimental results show that the proposed method can achieve a high resolution of 0.1 mm, stability of \u00b115 \u03bcm, a relatively large measurement range of 175 mm, and a high signal-to-noise ratio of 30 dB. The sensing length can be extended to 1.25 m with a weakened signal-to-noise ratio of 10 dB. The proposed method has broad development prospects in the field of intelligent industry and extreme environments.<\/jats:p>","DOI":"10.3390\/s22124480","type":"journal-article","created":{"date-parts":[[2022,6,14]],"date-time":"2022-06-14T03:00:17Z","timestamp":1655175617000},"page":"4480","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["High-Resolution and Large-Sensing-Range Liquid-Level Sensor Based on Optical Frequency Domain Reflectometry and No-Core Fiber"],"prefix":"10.3390","volume":"22","author":[{"given":"Guolu","family":"Yin","sequence":"first","affiliation":[{"name":"Key Laboratory of Optoelectronic Technology & Systems (Ministry of Education), Chongqing University, Chongqing 400044, China"},{"name":"State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Pengxi","family":"Yang","sequence":"additional","affiliation":[{"name":"Key Laboratory of Optoelectronic Technology & Systems (Ministry of Education), Chongqing University, Chongqing 400044, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hu","family":"Xiao","sequence":"additional","affiliation":[{"name":"Key Laboratory of Optoelectronic Technology & Systems (Ministry of Education), Chongqing University, Chongqing 400044, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yu","family":"Wang","sequence":"additional","affiliation":[{"name":"Key Laboratory of Optoelectronic Technology & Systems (Ministry of Education), Chongqing University, Chongqing 400044, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zeheng","family":"Zhang","sequence":"additional","affiliation":[{"name":"Key Laboratory of Optoelectronic Technology & Systems (Ministry of Education), Chongqing University, Chongqing 400044, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Fabing","family":"Yan","sequence":"additional","affiliation":[{"name":"Key Laboratory of Optoelectronic Technology & Systems (Ministry of Education), Chongqing University, Chongqing 400044, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tao","family":"Zhu","sequence":"additional","affiliation":[{"name":"Key Laboratory of Optoelectronic Technology & Systems (Ministry of Education), Chongqing University, Chongqing 400044, China"},{"name":"State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,6,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"7179","DOI":"10.1109\/JSEN.2019.2915031","article-title":"Optical fiber sensing for sub-millimeter liquid-level monitoring: A review","volume":"19","author":"Diaz","year":"2019","journal-title":"IEEE Sens. J."},{"key":"ref_2","first-page":"582","article-title":"An accurate detection for dynamic liquid level based on MIMO ultrasonic transducer array","volume":"64","author":"Li","year":"2014","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.sna.2007.04.027","article-title":"Liquid-level measurement system based on a remote grounded capacitive sensor","volume":"138","author":"Reverter","year":"2007","journal-title":"Sens. Actuators A"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1177\/0020294014546943","article-title":"A review on capacitive-type sensor for measurement of height of liquid level","volume":"47","author":"Kumar","year":"2014","journal-title":"Meas. Control"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"2892","DOI":"10.1109\/TIM.2018.2830678","article-title":"A liquid-level sensor based on a hollow coaxial cable fabry\u2013perot resonator with micrometer resolution","volume":"67","author":"Zhu","year":"2018","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"3425","DOI":"10.1364\/OL.36.003425","article-title":"Fiber-optic sensor for liquid level measurement","volume":"36","author":"LiKamWa","year":"2011","journal-title":"Opt. Lett."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"5515","DOI":"10.1109\/JSEN.2017.2724849","article-title":"Increasing the sensitivity of an optic level sensor with a wavelength and phase sensitive single-mode multimode single-mode fiber structure","volume":"17","author":"Fuentes","year":"2017","journal-title":"IEEE Sens. J."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1016\/j.sna.2016.04.046","article-title":"Liquid level measurement based on a no-core fiber with temperature compensation using a fiber Bragg grating","volume":"245","author":"Li","year":"2016","journal-title":"Sens. Actuators A"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"237","DOI":"10.1016\/j.sna.2018.07.056","article-title":"The liquid level monitoring with sub-millimeter resolution by discrete wavelength sampling method","volume":"282","author":"Yi","year":"2018","journal-title":"Sens. Actuators A"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Zhang, F., Li, S., Yan, X., Zhang, X., Wang, F., Suzuki, T., and Cheng, T. (2020). A refractive index sensitive liquid level monitoring sensor based on multimode interference. Photonics, 7.","DOI":"10.3390\/photonics7040089"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"3984","DOI":"10.1109\/JSEN.2015.2406872","article-title":"All-fiber Mach\u2013Zehnder interferometer for liquid level measurement","volume":"15","author":"Sun","year":"2015","journal-title":"IEEE Sens. J."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"169","DOI":"10.1364\/OL.45.000169","article-title":"Highly sensitive liquid-level sensor based on an optical reflective microfiber probe","volume":"45","author":"Wang","year":"2020","journal-title":"Opt. Lett."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"7870","DOI":"10.1364\/OE.449485","article-title":"In-line reflected fiber sensor for simultaneous measurement of temperature and liquid level based on tapered few-mode fiber","volume":"30","author":"Li","year":"2022","journal-title":"Opt. Express"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"2125","DOI":"10.1364\/OL.44.002125","article-title":"Sub-micrometer resolution liquid level sensor based on a hollow core fiber structure","volume":"44","author":"Liu","year":"2019","journal-title":"Opt. Lett."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"113134","DOI":"10.1016\/j.sna.2021.113134","article-title":"High sensitivity liquid level sensor for microfluidic applications using a hollow core fiber structure","volume":"332","author":"Liu","year":"2021","journal-title":"Sens. Actuators A"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"4882","DOI":"10.1109\/JSEN.2019.2895549","article-title":"Low-cost and high-performance optical fiber-based sensor for liquid level monitoring","volume":"19","author":"Martins","year":"2019","journal-title":"IEEE Sens. J."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"268","DOI":"10.1109\/LPT.2015.2494611","article-title":"An ultra-sensitive liquid-level indicator based on an etched chirped-fiber Bragg grating","volume":"28","author":"Chang","year":"2016","journal-title":"IEEE Photonics Technol. Lett."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"125104","DOI":"10.1088\/0957-0233\/27\/12\/125104","article-title":"Intensity liquid level sensor based on multimode interference and fiber Bragg grating","volume":"27","author":"Oliveira","year":"2016","journal-title":"Meas. Sci. Technol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"2878","DOI":"10.1109\/JSEN.2011.2145416","article-title":"Implementation and characterization of liquid-level sensor based on a long-period fiber grating Mach\u2013Zehnder interferometer","volume":"11","author":"Fu","year":"2011","journal-title":"IEEE Sens. J."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Pan, Z., Huang, Y., and Xiao, H. (2018). Multi-parameter sensing device to detect liquid layers using long-period fiber gratings. Sensors, 18.","DOI":"10.3390\/s18093094"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"114","DOI":"10.1016\/j.sna.2018.09.014","article-title":"Liquid level sensing for harsh environment applications using distributed fiber optic temperature measurements","volume":"282","author":"Petrie","year":"2018","journal-title":"Sens. Actuators A"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"795","DOI":"10.1364\/AO.382725","article-title":"Liquid-level sensing method based on differential pulse-width pair Brillouin optical time-domain analysis and a self-heated high attenuation fiber","volume":"59","author":"Zhang","year":"2020","journal-title":"Appl. Opt."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1023","DOI":"10.1109\/JLT.2018.2885226","article-title":"Chaotic correlation optical fiber liquid level sensor","volume":"37","author":"Wang","year":"2018","journal-title":"J. Lightwave Technol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"11538","DOI":"10.1364\/OE.412935","article-title":"High resolution and large sensing range liquid level measurement using phase-sensitive optic distributed sensor","volume":"29","author":"Liu","year":"2021","journal-title":"Opt. Express"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"837","DOI":"10.1109\/JLT.2021.3123725","article-title":"In-fiber auxiliary interferometer to compensate laser nonlinear tuning in simplified OFDR","volume":"40","author":"Yin","year":"2021","journal-title":"J. Lightwave Technol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"5845","DOI":"10.1364\/OE.17.005845","article-title":"Analysis and suppression of nonlinear frequency modulation in an optical frequency-domain reflectometer","volume":"17","author":"Wuilpart","year":"2009","journal-title":"Opt. Express"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"16140","DOI":"10.1364\/OE.390549","article-title":"Distributed directional torsion sensing based on an optical frequency domain reflectometer and a helical multicore fiber","volume":"28","author":"Yin","year":"2020","journal-title":"Opt. 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