{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,1]],"date-time":"2026-07-01T03:20:14Z","timestamp":1782876014572,"version":"3.54.5"},"reference-count":12,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2019,8,22]],"date-time":"2019-08-22T00:00:00Z","timestamp":1566432000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["51575140"],"award-info":[{"award-number":["51575140"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Heilongjiang Province Outstanding Youth Science Fund Project","award":["HSF20190040"],"award-info":[{"award-number":["HSF20190040"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Tuning nonlinearity of the laser is the main source of deterioration of the spatial resolution in optical frequency-domain reflectometry (OFDR) system. In this paper, we develop methods for tuning nonlinearity correction in an OFDR system from the aspect of data acquisition and post-processing. An external clock based on a zero-crossing detection is researched and implemented using a customized circuit. Equal-spacing frequency sampling is, therefore, achieved in real-time. The zero-crossing detection for the beating frequency of 20 MHz is achieved. The maximum sensing distance can reach the same length of the auxiliary interferometer. Moreover, a nonlinearity correction method based on the self-reference method is proposed. The auxiliary interferometer is no longer necessary in this scheme. The tuning information of the laser is extracted by a strong reflectivity point at the end of the measured fiber. The tuning information is then used to resample the raw signal, and the nonlinearity correction can be achieved. The spatial resolution test and the distributed strain measurement test were both performed based on this nonlinearity correction method. The results validated the feasibility of the proposed method. This method reduces the hardware and data burden for the system and has potential value for system integration and miniaturization.<\/jats:p>","DOI":"10.3390\/s19173660","type":"journal-article","created":{"date-parts":[[2019,8,23]],"date-time":"2019-08-23T10:15:07Z","timestamp":1566555307000},"page":"3660","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":32,"title":["Nonlinearity Correction in OFDR System Using a Zero-Crossing Detection-Based Clock and Self-Reference"],"prefix":"10.3390","volume":"19","author":[{"given":"Shiyuan","family":"Zhao","sequence":"first","affiliation":[{"name":"Center of Ultra-Precision Optoelectronic Instrument, Harbin Institute of Technology, Harbin 150080, China"},{"name":"Key Lab of Ultra-Precision Intelligent Instrumentation, Harbin Institute of Technology, Ministry of Industry and Information Technology, Harbin 150080, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jiwen","family":"Cui","sequence":"additional","affiliation":[{"name":"Center of Ultra-Precision Optoelectronic Instrument, Harbin Institute of Technology, Harbin 150080, China"},{"name":"Key Lab of Ultra-Precision Intelligent Instrumentation, Harbin Institute of Technology, Ministry of Industry and Information Technology, Harbin 150080, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jiubin","family":"Tan","sequence":"additional","affiliation":[{"name":"Center of Ultra-Precision Optoelectronic Instrument, Harbin Institute of Technology, Harbin 150080, China"},{"name":"Key Lab of Ultra-Precision Intelligent Instrumentation, Harbin Institute of Technology, Ministry of Industry and Information Technology, Harbin 150080, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2019,8,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1735","DOI":"10.1364\/AO.37.001735","article-title":"High-spatial-resolution distributed strain measurement in optical fiber with Rayleigh scatter","volume":"37","author":"Froggatt","year":"1998","journal-title":"Appl. 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