{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T04:24:33Z","timestamp":1760243073895,"version":"build-2065373602"},"reference-count":20,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2015,8,28]],"date-time":"2015-08-28T00:00:00Z","timestamp":1440720000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>A ratiometric wavelength measurement based on a Silicon-on-Insulator (SOI) integrated device is proposed and designed, which consists of directional couplers acting as two edge filters with opposite spectral responses. The optimal separation distance between two parallel silicon waveguides and the interaction length of the directional coupler are designed to meet the desired spectral response by using local supermodes. The wavelength discrimination ability of the designed ratiometric structure is demonstrated by a beam propagation method numerically and then is verified experimentally. The experimental results have shown a general agreement with the theoretical models. The ratiometric wavelength system demonstrates a resolution of better than 50 pm at a wavelength around 1550 nm with ease of assembly and calibration.<\/jats:p>","DOI":"10.3390\/s150921280","type":"journal-article","created":{"date-parts":[[2015,9,1]],"date-time":"2015-09-01T10:55:58Z","timestamp":1441104958000},"page":"21280-21293","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["A Ratiometric Wavelength Measurement Based on a  Silicon-on-Insulator Directional Coupler Integrated Device"],"prefix":"10.3390","volume":"15","author":[{"given":"Pengfei","family":"Wang","sequence":"first","affiliation":[{"name":"Photonic Research Centre, Dublin Institute of Technology, Kevin Street, Dublin 8, Ireland"},{"name":"Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ, UK"}]},{"given":"Agus","family":"Hatta","sequence":"additional","affiliation":[{"name":"Department of Engineering Physics, Faculty of Industrial Technology,  Institut Teknologi Sepuluh Nopember, Surabaya, Sukolilo 60111, Indonesia"}]},{"given":"Haoyu","family":"Zhao","sequence":"additional","affiliation":[{"name":"Key laboratory of In-fiber Integrated Optics of Ministry of Education, College of Science,  Harbin Engineering University, Harbin 150001, China"}]},{"given":"Jie","family":"Zheng","sequence":"additional","affiliation":[{"name":"State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7187-2127","authenticated-orcid":false,"given":"Gerald","family":"Farrell","sequence":"additional","affiliation":[{"name":"Photonic Research Centre, Dublin Institute of Technology, Kevin Street, Dublin 8, Ireland"}]},{"given":"Gilberto","family":"Brambilla","sequence":"additional","affiliation":[{"name":"Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ, UK"}]}],"member":"1968","published-online":{"date-parts":[[2015,8,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1442","DOI":"10.1109\/50.618377","article-title":"Fiber grating sensors","volume":"15","author":"Kersey","year":"1997","journal-title":"J. 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