{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,28]],"date-time":"2026-02-28T17:45:52Z","timestamp":1772300752448,"version":"3.50.1"},"reference-count":18,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2021,1,19]],"date-time":"2021-01-19T00:00:00Z","timestamp":1611014400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Photonics"],"abstract":"<jats:p>We present a giant sensitivity displacement sensor combining the push-pull method and enhanced Vernier effect. The displacement sensor consists in two interferometers that are composed by two cleaved standard optical fibers coupled by a 3 dB coupler and combined with a double-sided mirror. The push pull-method is applied to the mirror creating a symmetrical change to the length of each interferometer. Furthermore, we demonstrate that the Vernier effect has a maximum sensitivity of two-fold that obtained with a single interferometer. The combination of the push-pull method and the Vernier effect in the displacement sensors allows a sensitivity of 60 \u00b1 1 nm\/\u03bcm when compared with a single interferometer working in the same free spectral range. In addition, exploring the maximum performance of the displacement sensors, a sensitivity of 254 \u00b1 6 nm\/\u03bcm is achieved, presenting a M-factor of 1071 and MVernier of 1.9 corresponding to a resolution of 79 pm. This new solution allows the implementation of giant-sensitive displacement measurement for a wide range of applications.<\/jats:p>","DOI":"10.3390\/photonics8010023","type":"journal-article","created":{"date-parts":[[2021,1,20]],"date-time":"2021-01-20T03:34:25Z","timestamp":1611113665000},"page":"23","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Giant Displacement Sensitivity Using Push-Pull Method in Interferometry"],"prefix":"10.3390","volume":"8","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0384-1924","authenticated-orcid":false,"given":"Paulo","family":"Robalinho","sequence":"first","affiliation":[{"name":"INESC TEC\u2014Institute for Systems and Computer Engineering, Technology and Science, Rua do Campo Alegre 687, 4169-007 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7680-1056","authenticated-orcid":false,"given":"Orlando","family":"Fraz\u00e3o","sequence":"additional","affiliation":[{"name":"INESC TEC\u2014Institute for Systems and Computer Engineering, Technology and Science, Rua do Campo Alegre 687, 4169-007 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2021,1,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"72","DOI":"10.1038\/scientificamerican1160-72","article-title":"Fiber optics","volume":"203","author":"Kapany","year":"1960","journal-title":"Sci. Am."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"M-Hern\u00e1ndez, M.E., Goicoechea, J., and Arregui, F.J. (2019). Hg2+ Optical Fiber Sensor Based on LSPR Generated by Gold Nanoparticles Embedded in LBL Nano-Assembled Coatings. Sensors, 19.","DOI":"10.3390\/s19224906"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Maciak, E. (2019). Low-Coherence Interferometric Fiber Optic Sensor for Humidity Monitoring Based on Nafion\u00ae Thin Film. Sensors, 19.","DOI":"10.3390\/s19030629"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"85","DOI":"10.1016\/j.sna.2004.03.038","article-title":"Applications of a high accuracy optical fiber displacement sensor to vibrometry and profilometry","volume":"116","author":"Alayli","year":"2004","journal-title":"Sens. Actuators A Phys."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Tabassum, S., Wang, Y., Qu, J., Wang, Q., Oren, S., Weber, R.J., Lu, M., Kumar, R., and Dong, L. (November, January 30). Patterning of Nanophotonic Structures at Optical Fiber Tip for Refractive Index Sensing. Proceedings of the 2016 IEEE SENSORS, Orlando, FL, USA.","DOI":"10.1109\/ICSENS.2016.7808581"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"14690","DOI":"10.1364\/OE.24.014690","article-title":"In-fiber Fabry-Perot interferometer for strain and magnetic field sensing","volume":"24","author":"Costa","year":"2016","journal-title":"Opt. Express"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"521","DOI":"10.1016\/j.snb.2016.06.119","article-title":"Fiber optic SPR sensor for refractive index and temperature measurement based on MMF-FBG-MMF structure","volume":"237","author":"Hu","year":"2016","journal-title":"Sens. Actuators B Chem."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1016\/j.sna.2019.03.011","article-title":"Ultrasensitive refractive index sensor based on parallel-connected dual Fabry-Perot interferometers with Vernier effect","volume":"290","author":"Yao","year":"2019","journal-title":"Sens. Actuators A Phys."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"415","DOI":"10.1016\/j.yofte.2018.07.023","article-title":"A high-sensitivity optical fiber relative humidity sensor based on microsphere WGM resonator","volume":"45","author":"Liang","year":"2018","journal-title":"Opt. Fiber Technol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"22242","DOI":"10.1364\/OE.19.022242","article-title":"Coupled optofluidic ring laser for ultrahigh-sensitive sensing","volume":"19","author":"Zhang","year":"2011","journal-title":"Opt. Express"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"108451","DOI":"10.1016\/j.measurement.2020.108451","article-title":"Fiber-optic sensors based on Vernier effect","volume":"167","author":"Liu","year":"2021","journal-title":"Measurement"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"837","DOI":"10.1109\/LPT.2014.2308327","article-title":"M\u2013Z Interferometer Constructed by Two S-Bend Fibers for Displacement and Force Measurements","volume":"26","author":"Chen","year":"2014","journal-title":"IEEE Photonics Technol. Lett."},{"key":"ref_13","first-page":"10","article-title":"High-precision micro-displacement optical-fiber sensor based on surface plasmon resonance","volume":"42","author":"Zhu","year":"2017","journal-title":"Opt. Lett."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"2324","DOI":"10.1109\/JLT.2016.2535662","article-title":"A Highly Sensitive Fibre-Optic Nano-Displacement Sensor Based on Surface Plasmon Resonance","volume":"34","author":"Wang","year":"2016","journal-title":"J. Light. Technol."},{"key":"ref_15","unstructured":"Robalinho, P., Gomes, A.D., and Fraz\u00e3o, O. (2020). Colossal enhancement of strain sensitivity using the push-pull deformation method. IEEE Sens. J., 1."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Gomes, A.D., Ferreira, M.S., Bierlich, J., Kobelke, J., Rothhardt, M., Bartel, H., and Fraz\u00e3o, O. (2019). Optical Harmonic Vernier Effect: A New Tool for High Performance Interferometric Fiber Sensors. Sensor, 19.","DOI":"10.3390\/s19245431"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"4145","DOI":"10.1364\/OE.384815","article-title":"Ultrasensitive refractive index sensor based on enhanced Vernier effect through cascaded fiber core-offset pairs","volume":"28","author":"Li","year":"2020","journal-title":"Opt. Express"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1139","DOI":"10.1109\/LPT.2020.3014695","article-title":"High Enhancement Strain Sensor Based on Vernier Effect Using 2-Fiber Loop Mirrors","volume":"32","author":"Robalinho","year":"2020","journal-title":"IEEE Photonics Technol. Lett."}],"container-title":["Photonics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2304-6732\/8\/1\/23\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T05:12:57Z","timestamp":1760159577000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2304-6732\/8\/1\/23"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,1,19]]},"references-count":18,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2021,1]]}},"alternative-id":["photonics8010023"],"URL":"https:\/\/doi.org\/10.3390\/photonics8010023","relation":{},"ISSN":["2304-6732"],"issn-type":[{"value":"2304-6732","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,1,19]]}}}