{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T05:06:36Z","timestamp":1787029596459,"version":"build-2736575974"},"reference-count":38,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2023,7,9]],"date-time":"2023-07-09T00:00:00Z","timestamp":1688860800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"publisher","award":["NRF-2021R1A4A1031660"],"award-info":[{"award-number":["NRF-2021R1A4A1031660"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"publisher","award":["KIMM-NK242"],"award-info":[{"award-number":["KIMM-NK242"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Korea Institute of Machinery &amp; Materials","award":["NRF-2021R1A4A1031660"],"award-info":[{"award-number":["NRF-2021R1A4A1031660"]}]},{"name":"Korea Institute of Machinery &amp; Materials","award":["KIMM-NK242"],"award-info":[{"award-number":["KIMM-NK242"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>We present a phase-locked synthetic wavelength interferometer that enables a complete elimination of cyclic errors in absolute distance measurements. With this method, the phase difference between the reference and measurement paths is fed back into a phase lock-in system, which is then used to control the synthetic wavelength and set the phase difference to zero using an external cavity acousto-optic modulator. We validated the cyclic error removal of the proposed phase-locked method by comparing it with the conventional phase-measuring method of the synthetic wavelength interferometer. By analyzing the locked error signal, we achieved a precision of 0.6 mrad in phase without any observed cyclic errors.<\/jats:p>","DOI":"10.3390\/s23146253","type":"journal-article","created":{"date-parts":[[2023,7,10]],"date-time":"2023-07-10T01:02:50Z","timestamp":1688950970000},"page":"6253","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Phase-Locked Synthetic Wavelength Interferometer Using a Femtosecond Laser for Absolute Distance Measurement without Cyclic Error"],"prefix":"10.3390","volume":"23","author":[{"given":"Hyeokin","family":"Kang","sequence":"first","affiliation":[{"name":"Department of Mechanical System Design Engineering, Seoul National University of Science and Technology (Seoultech), 232 Gongneung-ro, Nowon-gu, Seoul 01811, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joohyung","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Mechanical System Design Engineering, Seoul National University of Science and Technology (Seoultech), 232 Gongneung-ro, Nowon-gu, Seoul 01811, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4271-5771","authenticated-orcid":false,"given":"Young-Jin","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Science Town, Daejeon 34141, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0235-1739","authenticated-orcid":false,"given":"Seung-Woo","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Science Town, Daejeon 34141, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,7,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1038\/416233a","article-title":"Optical frequency metrology","volume":"416","author":"Udem","year":"2002","journal-title":"Nature"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"635","DOI":"10.1126\/science.288.5466.635","article-title":"Carrier-Envelope Phase Control of Femtosecond Mode-Locked Lasers and Direct Optical Frequency Synthesis","volume":"288","author":"Jones","year":"2000","journal-title":"Science"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"6501","DOI":"10.1126\/science.aay3676","article-title":"Optical frequency combs: Coherently uniting the electromagnetic spectrum","volume":"369","author":"Diddams","year":"2020","journal-title":"Science"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"186","DOI":"10.1038\/nphoton.2011.38","article-title":"Searching for applications with a fine-tooth comb","volume":"5","author":"Newbury","year":"2011","journal-title":"Nat. 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