{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,25]],"date-time":"2026-04-25T07:35:36Z","timestamp":1777102536426,"version":"3.51.4"},"reference-count":21,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2022,9,8]],"date-time":"2022-09-08T00:00:00Z","timestamp":1662595200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Natural Science Foundation of China","award":["11774432"],"award-info":[{"award-number":["11774432"]}]},{"name":"National Natural Science Foundation of China","award":["51509252"],"award-info":[{"award-number":["51509252"]}]},{"name":"National Natural Science Foundation of China","award":["41874091"],"award-info":[{"award-number":["41874091"]}]},{"name":"National Natural Science Foundation of China","award":["52071245"],"award-info":[{"award-number":["52071245"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The demodulation algorithm based on 3 \u00d7 3 coupler in a fiber-optic hydrophone array has gained extensive attention in recent years. The traditional method uses a circulator to construct the normal path-match interferometry; however, the problem of increasing the asymmetry of the three-way signal to be demodulated is easily overlooked. To provide a solution, we report a pretreatment method for hydrophone array based on 3 \u00d7 3 coupler demodulation. We use cubic spline interpolation to perform nonlinear fitting to the reflected pulse train and calculate the peak-to-peak values of the single pulse to determine the light intensity compensation coefficient of the interference signal, so as to demodulate the corrected three-way interference signal. For experimental verification, ultra-weak fiber Bragg gratings (uwFBGs) with reflectivity of \u221250 dB are applied to construct a hydrophone array with 800 sensors, and a vibratory liquid column method is set up to generate a low-frequency hydroacoustic signal. Compared to the traditional demodulation algorithm based on a 3 \u00d7 3 coupler, the pretreatment method can improve the consistency of interference signals. The Lissajous figures show that cubic spline interpolation can improve the accuracy of monopulse peak seeking results by about 1 dB, and intensity compensation can further lead to a much lower noise density level for the interference pulse amplitude\u2014specifically, more than 7 dB at 5~50 Hz\u2014and the signal-to-noise ratio is improved by approximately 10 dB at 10 Hz. The distinct advantages of the proposed pretreatment method make it an excellent candidate for a hydrophone array system based on path-match interferometry.<\/jats:p>","DOI":"10.3390\/s22186814","type":"journal-article","created":{"date-parts":[[2022,9,8]],"date-time":"2022-09-08T20:50:27Z","timestamp":1662670227000},"page":"6814","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":13,"title":["Pretreatment of Ultra-Weak Fiber Bragg Grating Hydrophone Array Based on Cubic Spline Interpolation Using Intensity Compensation"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2800-767X","authenticated-orcid":false,"given":"Yandong","family":"Pang","sequence":"first","affiliation":[{"name":"Department of Weaponry Engineering, Naval Engineering University, Wuhan 430070, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8453-1420","authenticated-orcid":false,"given":"Hanjie","family":"Liu","sequence":"additional","affiliation":[{"name":"National Engineering Laboratory for Fiber Optic Sensor Technology, Wuhan University of Technology, Wuhan 430032, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8863-7334","authenticated-orcid":false,"given":"Ciming","family":"Zhou","sequence":"additional","affiliation":[{"name":"National Engineering Laboratory for Fiber Optic Sensor Technology, Wuhan University of Technology, Wuhan 430032, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Junbin","family":"Huang","sequence":"additional","affiliation":[{"name":"Department of Weaponry Engineering, Naval Engineering University, Wuhan 430070, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hongcan","family":"Gu","sequence":"additional","affiliation":[{"name":"Department of Weaponry Engineering, Naval Engineering University, Wuhan 430070, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zhiqiang","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Weaponry Engineering, Naval Engineering University, Wuhan 430070, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,9,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"673","DOI":"10.3189\/002214308786570827","article-title":"Spatially distributed temperatures at the base of two mountain snowpacks measured with fiber-optic sensors","volume":"54","author":"Tyler","year":"2008","journal-title":"J. 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