{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,15]],"date-time":"2026-01-15T05:10:20Z","timestamp":1768453820878,"version":"3.49.0"},"reference-count":39,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2024,8,28]],"date-time":"2024-08-28T00:00:00Z","timestamp":1724803200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Central Universities Basic Research Operating Costs of Ministry of Education B Key Laboratory Director\u2019s Fund Key Project","award":["GLAB2023ZR05"],"award-info":[{"award-number":["GLAB2023ZR05"]}]},{"name":"Zhangjiagang Leading Entrepreneurial and Innovative Talents (Team) Introduction Program","award":["GLAB2023ZR05"],"award-info":[{"award-number":["GLAB2023ZR05"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Bismuth germanate (Bi4Ge3O12, BGO) is a widely used optical sensing material with a high electro-optic coefficient, ideal for optical electric field sensors. Achieving high precision in electric field sensing requires fabricating optical waveguides on BGO. Traditional waveguide writing methods face challenges with this material. This study explores using femtosecond laser writing technology for preparing waveguides on BGO, leveraging ultrafast optical fields for superior material modification. Our experimental analysis shows that a cladding-type waveguide, written with a femtosecond laser at 200 kHz repetition frequency and 10.15 mW average power (pulse energy of 50.8 nJ), exhibits excellent light-guiding characteristics. Simulations of near-field optical intensity distribution and refractive index variations using the refractive index reconstruction method demonstrate that the refractive index modulation ensures single-mode transmission and effectively confines light to the core layer. In situ refractive index characterization confirms the feasibility of fabricating a waveguide with a refractive index reduction on BGO. The resulting waveguide has a loss per unit length of approximately 1.2 dB\/cm, marking a successful fabrication. Additionally, we design an antenna electrode, analyze sensor performance indicators, and integrate a preparation process plan for the antenna electrode. This achievement establishes a solid experimental foundation for future studies on BGO crystal waveguides in electric field measurement applications.<\/jats:p>","DOI":"10.3390\/s24175570","type":"journal-article","created":{"date-parts":[[2024,8,28]],"date-time":"2024-08-28T07:52:08Z","timestamp":1724831528000},"page":"5570","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Integrated Optical Waveguide Electric Field Sensors Based on Bismuth Germanate"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9719-9455","authenticated-orcid":false,"given":"Jin","family":"Wang","sequence":"first","affiliation":[{"name":"School of Mechanical Engineering and Electronic Information, China University of Geosciences, Wuhan 430074, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0000-3767-308X","authenticated-orcid":false,"given":"Yilin","family":"Song","sequence":"additional","affiliation":[{"name":"School of Mechanical Engineering and Electronic Information, China University of Geosciences, Wuhan 430074, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0007-9783-2530","authenticated-orcid":false,"given":"Xuefei","family":"Song","sequence":"additional","affiliation":[{"name":"School of Mechanical Engineering and Electronic Information, China University of Geosciences, Wuhan 430074, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-5401-4813","authenticated-orcid":false,"given":"Wei","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Mechanical Engineering and Electronic Information, China University of Geosciences, Wuhan 430074, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Junqi","family":"Yang","sequence":"additional","affiliation":[{"name":"School of Mechanical Engineering and Electronic Information, China University of Geosciences, Wuhan 430074, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-3620-4593","authenticated-orcid":false,"given":"Zhi","family":"Xuan","sequence":"additional","affiliation":[{"name":"School of Mechanical Engineering and Electronic Information, China University of Geosciences, Wuhan 430074, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2024,8,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"497","DOI":"10.1080\/716099675","article-title":"Optical Waveguide Theory","volume":"31","author":"Adams","year":"2010","journal-title":"Opt. 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