{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T03:24:33Z","timestamp":1760239473768,"version":"build-2065373602"},"reference-count":34,"publisher":"MDPI AG","issue":"22","license":[{"start":{"date-parts":[[2020,11,20]],"date-time":"2020-11-20T00:00:00Z","timestamp":1605830400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Start-up fund from Shantou University","award":["NTF19023","NTF18016"],"award-info":[{"award-number":["NTF19023","NTF18016"]}]},{"name":"The Optics and Photoelectronics Project","award":["2018KCXTD011"],"award-info":[{"award-number":["2018KCXTD011"]}]},{"name":"Specialized Project Fund in Science and Technology of Guangdong Province","award":["190827105565385","190827105545434"],"award-info":[{"award-number":["190827105565385","190827105545434"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this paper, an endlessly single mode microstructured polymer optical fiber (mPOF) in a Mach\u2013Zehnder (M\u2013Z) interferometer configuration is demonstrated for temperature and strain measurement. Because there is no commercial splicer applied for POF-silica optical fiber (SOF) connectorization, prior to the M\u2013Z interferometric sensing, we introduce an imaging projecting method to align a polycarbonate mPOF to a SOF and then the splice is cured permanently using ultraviolet (UV) glue. A He-Ne laser beam at 632.8 nm coupled in a SOF is divided by a 1 \u00d7 2 fiber coupler to propagate in two fiber arms. A piece of mPOF is inserted in one arm for sensing implementation and the interference fringes are monitored by a camera. For non-annealed fiber, the temperature sensitivity is found to be 25.5 fringes\/\u00b0C for increasing temperature and 20.6 fringes\/\u00b0C for decreasing temperature. The converted sensitivity per unit length is 135.6 fringes\/\u00b0C\/m for increasing temperature, which is twice as much as the silica fiber, or 852.2 rad\/\u00b0C\/m (optical phase change versus fiber temperature), which is more than four times as much as that for the PMMA fiber. To solve the sensitivity disagreement, the fiber was annealed at 125 \u00b0C for 36 h. Just after the thermal treatment, the temperature measurement was conducted with sensitivities of 16.8 fringes\/\u00b0C and 21.3 fringes\/\u00b0C for increasing and decreasing process, respectively. One month after annealing, the linear response was improved showing a temperature sensitivity of ~20.7 fringes\/\u00b0C in forward and reverse temperature measurement. For the strain measurement based on non-annealed fiber, the sensitivity was found to be ~1463 fringes\/%\u03b5 showing repeatable linear response for forward and reverse strain. The fiber axial force sensitivity was calculated to be ~2886 fringes\/N, showing a force measurement resolution of ~3.47 \u00d7 10\u22124 N. The sensing methodology adopted in this work shows several advantages, such as very low cost, high sensitivity, a straightforward sensing mechanism, and ease of fabrication.<\/jats:p>","DOI":"10.3390\/s20226643","type":"journal-article","created":{"date-parts":[[2020,11,20]],"date-time":"2020-11-20T02:09:07Z","timestamp":1605838147000},"page":"6643","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Polycarbonate mPOF-Based Mach\u2013Zehnder Interferometer for Temperature and Strain Measurement"],"prefix":"10.3390","volume":"20","author":[{"given":"Xiaoyu","family":"Yue","sequence":"first","affiliation":[{"name":"Research Center for Advanced Optics and Photoelectronics, Department of Physics, College of Science, Shantou University, Shantou 515063, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Haijin","family":"Chen","sequence":"additional","affiliation":[{"name":"Research Center for Advanced Optics and Photoelectronics, Department of Physics, College of Science, Shantou University, Shantou 515063, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hang","family":"Qu","sequence":"additional","affiliation":[{"name":"Research Center for Advanced Optics and Photoelectronics, Department of Physics, College of Science, Shantou University, Shantou 515063, China"},{"name":"Key Laboratory of Intelligent Manufacturing Technology of MOE, Shantou University, Shantou 515063, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Rui","family":"Min","sequence":"additional","affiliation":[{"name":"Center for Cognition and Neuroergonomics, State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University at Zhuhai, Zhuhai 519087, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2164-9453","authenticated-orcid":false,"given":"Getinet","family":"Woyessa","sequence":"additional","affiliation":[{"name":"DTU Fotonik, Department of Photonics Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8041-9156","authenticated-orcid":false,"given":"Ole","family":"Bang","sequence":"additional","affiliation":[{"name":"DTU Fotonik, Department of Photonics Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0239-6144","authenticated-orcid":false,"given":"Xuehao","family":"Hu","sequence":"additional","affiliation":[{"name":"Research Center for Advanced Optics and Photoelectronics, Department of Physics, College of Science, Shantou University, Shantou 515063, China"},{"name":"Key Laboratory of Intelligent Manufacturing Technology of MOE, Shantou University, Shantou 515063, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,11,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"18807","DOI":"10.1364\/OE.22.018807","article-title":"Highly reflective Bragg gratings in slightly etched step-index polymer optical fiber","volume":"22","author":"Hu","year":"2014","journal-title":"Opt. 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