{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,6]],"date-time":"2025-12-06T16:44:13Z","timestamp":1765039453427,"version":"build-2065373602"},"reference-count":24,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2019,1,15]],"date-time":"2019-01-15T00:00:00Z","timestamp":1547510400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100002347","name":"Bundesministerium f\u00fcr Bildung und Forschung","doi-asserted-by":"publisher","award":["03Z22A511"],"award-info":[{"award-number":["03Z22A511"]}],"id":[{"id":"10.13039\/501100002347","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>A grating-less fiber vector bend sensor is demonstrated using a standard single mode fiber spliced to a multimode fiber as a multimode interference device. The ring-shaped light intensity distribution at the end of the multimode fiber is subject to a vector transition in response to the fiber bend. Instead of comprehensive imaging processing for the analysis, the image can be tapped out by a seven-core fiber spliced to the other end of the multimode fiber. The seven-core fiber is further guided to seven single mode fibers via a commercial fan-out device. By comparing the relative light intensities received at the seven outputs, both the bend radius and its direction can be determined. Experiment has shown that a slight bend displacement of 10 \u00b5m over a 1.2-cm-long multimode fiber in the X direction (bend angle of 0.382\u00b0) causes a distinctive power imbalance of 4.6 dB between two chosen outputs (numbered C4 and C7). For the same displacement in the Y direction, the power ratio between the previous two outputs C4 and C7 remains constant, while the imbalance between another pair (C3 and C4) rises significantly to 7.0 dB.<\/jats:p>","DOI":"10.3390\/s19020321","type":"journal-article","created":{"date-parts":[[2019,1,16]],"date-time":"2019-01-16T03:09:13Z","timestamp":1547608153000},"page":"321","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Fiber Vector Bend Sensor Based on Multimode Interference and Image Tapping"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7952-8718","authenticated-orcid":false,"given":"Ziyang","family":"Zhang","sequence":"first","affiliation":[{"name":"School of Engineering, Westlake University, 18 Shilongshan Road, Hangzhou 310024, China"},{"name":"Institute of Advanced Technology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7563-0304","authenticated-orcid":false,"given":"Aashia","family":"Rahman","sequence":"additional","affiliation":[{"name":"innoFSPEC, Leibniz Institute for Astrophysics (AIP), an der Sternwarte 16, 14482 Potsdam, Germany"}]},{"given":"Julia","family":"Fiebrandt","sequence":"additional","affiliation":[{"name":"innoFSPEC, Leibniz Institute for Astrophysics (AIP), an der Sternwarte 16, 14482 Potsdam, Germany"},{"name":"PicoQuant GmbH, Rudower Chaussee 29, 12489 Berlin, Germany"}]},{"given":"Yu","family":"Wang","sequence":"additional","affiliation":[{"name":"innoFSPEC, Leibniz Institute for Astrophysics (AIP), an der Sternwarte 16, 14482 Potsdam, Germany"}]},{"given":"Kai","family":"Sun","sequence":"additional","affiliation":[{"name":"innoFSPEC, Leibniz Institute for Astrophysics (AIP), an der Sternwarte 16, 14482 Potsdam, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2645-3676","authenticated-orcid":false,"given":"Jiajun","family":"Luo","sequence":"additional","affiliation":[{"name":"innoFSPEC, Leibniz Institute for Astrophysics (AIP), an der Sternwarte 16, 14482 Potsdam, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6711-7137","authenticated-orcid":false,"given":"Kalaga","family":"Madhav","sequence":"additional","affiliation":[{"name":"innoFSPEC, Leibniz Institute for Astrophysics (AIP), an der Sternwarte 16, 14482 Potsdam, Germany"}]},{"given":"Martin M.","family":"Roth","sequence":"additional","affiliation":[{"name":"innoFSPEC, Leibniz Institute for Astrophysics (AIP), an der Sternwarte 16, 14482 Potsdam, Germany"}]}],"member":"1968","published-online":{"date-parts":[[2019,1,15]]},"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. Lightw. Technol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"2467","DOI":"10.3390\/s120302467","article-title":"Interferometric Fiber Optic Sensors","volume":"12","author":"Lee","year":"2012","journal-title":"Sensors"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"221","DOI":"10.1109\/LPT.2003.820117","article-title":"Simultaneous Strain and Temperature Measurements with Fiber Bragg Grating Written in Novel Hi-Bi Optical Fiber","volume":"16","author":"Chen","year":"2004","journal-title":"IEEE Photonics Technol. Lett."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"3508","DOI":"10.1364\/OL.39.003508","article-title":"Long period grating in multicore optical fiber: An ultra-sensitive vector bending sensor for low curvatures","volume":"39","author":"Saffari","year":"2014","journal-title":"Opt. Lett."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"2967","DOI":"10.1364\/OE.20.002967","article-title":"Shape sensing using multi-core fiber optic cable and parametric curve solutions","volume":"20","author":"Moore","year":"2012","journal-title":"Opt. Express"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"17415","DOI":"10.1038\/srep17415","article-title":"Compact Optical Fiber 3D Shape Sensor Based on a Pair of Orthogonal Tilted Fiber Bragg Gratings","volume":"5","author":"Feng","year":"2015","journal-title":"Sci. Rep."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"3109","DOI":"10.1364\/OL.40.003109","article-title":"Cladding waveguide gratings in standard single-mode fiber for 3D shape sensing","volume":"40","author":"Waltermann","year":"2015","journal-title":"Opt. Lett."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"035701","DOI":"10.1088\/2040-8986\/aaaa39","article-title":"Fiber-based three-dimensional multi-mode interference device as efficient power divider and vector curvature sensor","volume":"20","author":"Zhang","year":"2018","journal-title":"J. Opt."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Fiebrandt, J., Zhang, Z., Haynes, D., Wang, Y., Sun, K., and Roth, M.M. (2018). Multimode interference device in a rounded rectangle-core fiber. Advanced Photonics 2018 (BGPP, IPR, NP, NOMA, Sensors, Networks, SPPCom, SOF), OSA Technical Digest (Online), Optical Society of America. paper SoW4H.4.","DOI":"10.1364\/SOF.2018.SoW4H.4"},{"key":"ref_10","first-page":"2066","article-title":"Bending Vector Sensor Based on the Multimode-2-Core-Multimode Fiber Structure","volume":"28","author":"Wang","year":"2016","journal-title":"IEEE Photonics Technol. Lett."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"375","DOI":"10.1109\/LPT.2017.2786338","article-title":"Directional Bending Sensor Based on a Dual Side-Hole Fiber Mach\u2013Zehnder Interferometer","volume":"30","author":"Tian","year":"2018","journal-title":"IEEE Photonics Technol. Lett."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"3010","DOI":"10.1364\/OE.23.003010","article-title":"Micro-bending vector sensor based on six-airhole grapefruit microstructure fiber using lateral offset splicing","volume":"23","author":"Huang","year":"2015","journal-title":"Opt. Express"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"7718","DOI":"10.1364\/AO.51.007718","article-title":"Arrayed waveguide grating interrogator for fiber Bragg grating sensors: Measurement and simulation","volume":"51","author":"Koch","year":"2012","journal-title":"Appl. Opt."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Gifford, D.K., Froggatt, M.E., and Kreger, S.T. (2011). High precision, high sensitivity distributed displacement and temperature measurements using OFDR-based phase tracking. Proc. SPIE, 7753.","DOI":"10.1117\/12.885131"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"20183","DOI":"10.1364\/OE.25.020183","article-title":"Towards large dynamic range and ultrahigh measurement resolution in distributed fiber sensing based on multicore fiber","volume":"25","author":"Dang","year":"2017","journal-title":"Opt. Express"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1988","DOI":"10.1364\/OE.17.001988","article-title":"Efficient multi-mode to single-mode coupling in a photonic lantern","volume":"17","author":"Noordegraaf","year":"2009","journal-title":"Opt. Express"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"107","DOI":"10.1364\/AOP.7.000107","article-title":"The photonic lantern","volume":"7","author":"Birks","year":"2015","journal-title":"Adv. Opt. Photonics"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"317","DOI":"10.1364\/OL.31.000317","article-title":"All-fiber multimode-interference-based refractometer sensor: Proposal and design","volume":"31","author":"Wang","year":"2006","journal-title":"Opt. Lett."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"155","DOI":"10.1109\/LPT.2012.2230617","article-title":"Strain-Temperature Discrimination Using Multimode Interference in Tapered Fiber","volume":"25","author":"Andre","year":"2013","journal-title":"IEEE Photonics Technol. Lett."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"26929","DOI":"10.3390\/s151026929","article-title":"Highly Sensitive Liquid Core Temperature Sensor Based on Multimode Interference Effects","volume":"15","year":"2015","journal-title":"Sensors"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"832","DOI":"10.1364\/OL.41.000832","article-title":"Ultrasensitive vector bending sensor based on multicore optical fiber","volume":"41","author":"Villatoro","year":"2016","journal-title":"Opt. Lett."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Villatoro, J., Arrizabalaga, O., Antonio-Lopez, E., Zubia, J., and de Oc\u00e1riz, I.S. (2017). Multicore Fiber Sensors. Optical Fiber Communication Conference, Osa Technical Digest (Online), Optical Society of America. paper Th3H.1.","DOI":"10.1364\/OFC.2017.Th3H.1"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"5188","DOI":"10.1364\/OL.40.005188","article-title":"Bending sensor combining multicore fiber with a mode-selective photonic lantern","volume":"40","author":"Newkirk","year":"2015","journal-title":"Opt. Lett."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1337","DOI":"10.1109\/LPT.2018.2847233","article-title":"Single-mode to 61 spots divider with multimode interference in hexagonal core fiber","volume":"30","author":"Zhang","year":"2018","journal-title":"IEEE Photonics Technol. Lett."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/2\/321\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T12:26:00Z","timestamp":1760185560000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/2\/321"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,1,15]]},"references-count":24,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2019,1]]}},"alternative-id":["s19020321"],"URL":"https:\/\/doi.org\/10.3390\/s19020321","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2019,1,15]]}}}