{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,23]],"date-time":"2025-10-23T05:41:55Z","timestamp":1761198115061,"version":"build-2065373602"},"reference-count":44,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2022,9,24]],"date-time":"2022-09-24T00:00:00Z","timestamp":1663977600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Sapienza University"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>FBG sensors are used in many scientific and industrial fields for assessing the structural integrity of mechanical components and in very high (above 600 \u00b0C) or very low (cryogenic) temperature applications. The main concerns with the use of such sensors in applications involving extreme temperatures are related partly to the instability of the reflected spectrum, which tends to dissolve into the noise floor, and partly to the degradation of the mechanical properties of the optical fiber, which tends to worsen the inherent brittleness. All of this raises the need for a robust nickel protective coating to ensure the grating\u2019s integrity in high-temperature environments. In addition, the inherent brittleness of fiber-optic gratings leaves one to wonder whether it is possible to recover a broken, seemingly unusable sensor. In this way, a single-peak commercial FBG was intentionally broken in the middle of the grating length and re-spliced, inducing a strongly asymmetric chirped-like spectrum; then, a nickel coating was electrodeposited on its surface. The most important outcome achieved by this work is the regeneration of a highly distorted reflected spectrum through three thermal cycles performed from room temperature up to 500, 750, and 800 \u00b0C, respectively. After reaching a temperature of at least 700 \u00b0C, the spectrum, which has been drastically altered by splicing, becomes stable and restores its single peak shape. A further stabilization cycle carried out at 800 \u00b0C for 80 min led to an estimation of the stabilizing time of the new single-peak reflected spectrum.<\/jats:p>","DOI":"10.3390\/s22197255","type":"journal-article","created":{"date-parts":[[2022,9,26]],"date-time":"2022-09-26T03:34:17Z","timestamp":1664163257000},"page":"7255","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["FBG Spectrum Regeneration by Ni-Coating and High-Temperature Treatment"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4096-3592","authenticated-orcid":false,"given":"Carla","family":"Lupi","sequence":"first","affiliation":[{"name":"Dipartimento Ingegneria Chimica Materiali Ambiente, Sapienza Rome University, Via Eudossiana 18, 00184 Roma, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0793-4052","authenticated-orcid":false,"given":"Cristian","family":"Vendittozzi","sequence":"additional","affiliation":[{"name":"Campus FGA-UnB, Universidade de Bras\u00edlia, Bras\u00edlia 72444-240, DF, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7673-3556","authenticated-orcid":false,"given":"Erwin","family":"Ciro","sequence":"additional","affiliation":[{"name":"Dipartimento Ingegneria Chimica Materiali Ambiente, Sapienza Rome University, Via Eudossiana 18, 00184 Roma, Italy"},{"name":"Department of Engineering Sciences, Universit\u00e0 degli Studi Guglielmo Marconi, 00193 Rome, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ferdinando","family":"Felli","sequence":"additional","affiliation":[{"name":"Dipartimento Ingegneria Chimica Materiali Ambiente, Sapienza Rome University, Via Eudossiana 18, 00184 Roma, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,9,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"025107","DOI":"10.1088\/1555-6611\/aaf635","article-title":"Fiber Bragg grating temperature sensor of cladding with SrTiO3 thin film by pulsed laser deposition","volume":"29","author":"Cheng","year":"2019","journal-title":"Laser Phys."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"405","DOI":"10.1007\/s40009-020-01010-1","article-title":"Temperature Sensing with Fibre Bragg Grating and No-Core Fibre","volume":"44","author":"Daud","year":"2021","journal-title":"Natl. Acad. Sci. Lett."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Juraszek, J., and Antonik-Popio\u0142ek, P. (2021). Fibre optic fbg sensors for monitoring of the temperature of the building envelope. Materials, 14.","DOI":"10.3390\/ma14051207"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Xiang, Z., Wan, L., Gong, Z., Zhou, Z., Ma, Z., OuYang, X., He, Z., and Chan, C.C. (2019). Multifunctional textile platform for fiber optic wearable temperature-monitoring application. Micromachines, 10.","DOI":"10.3390\/mi10120866"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Ghorat, M., Gharehpetian, G.B., Latifi, H., Hejazi, M.A., and Bagheri, M. (2019). High-resolution FBG-based fiber-optic sensor with temperature compensation for PD monitoring. Sensors, 19.","DOI":"10.3390\/s19235285"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"5706","DOI":"10.1364\/OL.40.005706","article-title":"Type IIa Bragg grating based ultra-short DBR fiber laser with high temperature resistance","volume":"40","author":"Ran","year":"2015","journal-title":"Opt. Lett."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1109\/LPT.2013.2289967","article-title":"Enhanced temperature (~800 \u00b0C) stability of type-IIa FBG written by 255 nm beam","volume":"26","author":"Prakash","year":"2014","journal-title":"IEEE Photonics Technol. Lett."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"106650","DOI":"10.1016\/j.optlastec.2020.106650","article-title":"Regenerated Fibre Bragg Gratings: A critical assessment of more than 20 years of investigations","volume":"134","author":"Polz","year":"2021","journal-title":"Opt. Laser Technol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"236","DOI":"10.1016\/j.measurement.2015.09.020","article-title":"Regeneration, regenerated gratings and composite glass properties: The implications for high temperature micro and nano milling and optical sensing","volume":"79","author":"Canning","year":"2016","journal-title":"Meas. J. Int. Meas. Confed."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"3259","DOI":"10.1063\/1.1475366","article-title":"Fiber Bragg gratings with enhanced thermal stability","volume":"80","author":"Brambilla","year":"2002","journal-title":"Appl. Phys. Lett."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"275","DOI":"10.1002\/lpor.200810010","article-title":"Fibre gratings and devices for sensors and laser","volume":"2","author":"Canning","year":"2008","journal-title":"Laser Photonics Rev."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1016","DOI":"10.1364\/OL.27.001016","article-title":"Thermal stability of chemical composition gratings in fluorine-germanium-doped silica fibers","volume":"27","author":"Fokine","year":"2002","journal-title":"Opt. Lett."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Xia, H. (2012, January 4). Advanced Fiber Optical Sensor and Instrumentation for Power Generation Industrial Monitoring and Diagnostics. Proceedings of the SPIE Fiber Optic Sensors and Applications IX, Baltimore, MD, USA.","DOI":"10.1117\/12.922587"},{"key":"ref_14","unstructured":"Xia, H., McCarthy, K.T., Deng, K.-L.J., Lopez, F.J., and Avagliano, A.J. (2009). Fiber Bragg Grating for High Temperature Sensing. (No. 7,499,605), U.S. Patent."},{"key":"ref_15","first-page":"183","article-title":"Thermal regenerated type IIa fiber Bragg gratings for ultra-high temperature operation","volume":"284","author":"Lindner","year":"2011","journal-title":"OPTICS"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"6438","DOI":"10.1364\/OL.39.006438","article-title":"Thermal regenerated grating operation at temperatures up to 1400\u00b0C using new class of multimaterial glass-based photosensitive fiber","volume":"39","author":"Yang","year":"2014","journal-title":"Opt. Lett."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2360","DOI":"10.1364\/OL.29.002360","article-title":"Enhanced type IIA gratings for high-temperature operation","volume":"29","author":"Groothoff","year":"2004","journal-title":"Opt. Lett."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"586","DOI":"10.1364\/OL.35.000586","article-title":"Thermal stabilization of Type I fiber Bragg gratings for operation up to 600 \u00b0C","volume":"35","author":"Canning","year":"2010","journal-title":"Opt. Lett."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"27520","DOI":"10.1364\/OE.23.027520","article-title":"Influence of pre-annealing on the thermal regeneration of fiber Bragg gratings in standard optical fibers","volume":"23","author":"Holmberg","year":"2015","journal-title":"Opt. Express"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"368","DOI":"10.1016\/j.yofte.2018.08.013","article-title":"Temperature sensing characteristics of metal coated FBG during dynamic cooling process","volume":"45","author":"Li","year":"2018","journal-title":"Opt. Fiber Technol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1237","DOI":"10.1016\/j.ijleo.2015.10.234","article-title":"Beam propagation and mode coupling study in a coupled waveguide structure by using scalar finite element method","volume":"127","author":"Raghuwanshi","year":"2016","journal-title":"Optik"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"53","DOI":"10.12720\/jcm.14.1.53-57","article-title":"Impact of apodization profile on performance of fiber bragg grating strain\u2013temperature sensor","volume":"14","author":"Tahhan","year":"2019","journal-title":"J. Commun."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"012001","DOI":"10.1088\/1742-6596\/2049\/1\/012001","article-title":"Integration of chirping and apodization of Topas materials for improving the performance of fiber Bragg grating sensors","volume":"2049","author":"Saktioto","year":"2021","journal-title":"J. Phys. Conf. Ser."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"401","DOI":"10.1016\/j.optcom.2018.05.050","article-title":"Development and analysis of a model based on chirped fiber Bragg gratings employed for cracks characterization in materials","volume":"426","author":"Duchowicz","year":"2018","journal-title":"Opt. Commun."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"84","DOI":"10.1016\/j.yofte.2018.02.017","article-title":"Modeling FBG sensors sensitivity from cryogenic temperatures to room temperature as a function of metal coating thickness","volume":"42","author":"Vendittozzi","year":"2018","journal-title":"Opt. Fiber Technol."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Ross, M.J., Jenkins, R.B., Nelson, C., and Joyce, P. (2019). High temperature effects during high energy laser strikes on embedded fiber bragg grating sensors. Sensors, 19.","DOI":"10.3390\/s19061432"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1811","DOI":"10.1109\/LPT.2016.2572762","article-title":"An electroplating method for surface mounting optical fiber sensors on the metal substrate","volume":"28","author":"Li","year":"2016","journal-title":"IEEE Photonics Technol. Lett."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Li, C., Yang, W., Wang, M., Yu, X., Fan, J., Xiong, Y., Yang, Y., and Li, L. (2020). A review of coating materials used to improve the performance of optical fiber sensors. Sensors, 20.","DOI":"10.3390\/s20154215"},{"key":"ref_29","first-page":"246","article-title":"Railway overhead contact wire monitoring system by means of FBG sensor","volume":"57","author":"Lupi","year":"2021","journal-title":"Frat. Ed Integrit\u00e0 Strutt."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"095509","DOI":"10.1088\/1402-4896\/abb05c","article-title":"Fabrication and modification of temperature FBG sensor: Role of optical fiber type and Cu sputtered thickness","volume":"95","author":"Koo","year":"2020","journal-title":"Phys. Scr."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"012033","DOI":"10.1088\/1742-6596\/1892\/1\/012033","article-title":"Temperature sensitivity of FBG coating with zinc oxide and silicon carbide","volume":"1892","author":"Mansor","year":"2021","journal-title":"J. Phys. Conf. Ser."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"4791","DOI":"10.1109\/JLT.2019.2920120","article-title":"Electroless Nickel-Plating Sealing in FBG Pressure Sensor for Thermoelectric Power Plant Engines Applications","volume":"37","author":"Rosolem","year":"2019","journal-title":"J. Light. Technol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"102456","DOI":"10.1016\/j.rinp.2019.102456","article-title":"A novel high temperature resistant Mo-Cu functional gradient coating for optic fiber Bragg grating","volume":"14","author":"He","year":"2019","journal-title":"Results Phys."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Lupi, C., Felli, F., Dell\u2019Era, A., Ciro, E., Caponero, M.A., Kalinowski, H.J., and Vendittozzi, C. (2019). Critical Issues of Double-Metal Layer Coating on FBG for Applications at High Temperatures. Sens. Artic., 19.","DOI":"10.3390\/s19183824"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"7425","DOI":"10.1109\/JSEN.2019.2916639","article-title":"Analysis of fiber optic sensor embedded in metals by automatic and manual tig welding","volume":"19","author":"Grandal","year":"2019","journal-title":"IEEE Sens. J."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"N71","DOI":"10.1088\/0964-1726\/14\/6\/N02","article-title":"Metal coating for enhancing the sensitivity of fibre Bragg grating sensors at cryogenic temperature","volume":"14","author":"Lupi","year":"2005","journal-title":"Smart Mater. Struct."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"142","DOI":"10.1016\/j.cryogenics.2008.02.007","article-title":"Performance evaluation of metal-coated fiber Bragg grating sensors for sensing cryogenic temperature","volume":"48","author":"Suesser","year":"2008","journal-title":"Cryogenics"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"106768","DOI":"10.1016\/j.optlastec.2020.106768","article-title":"Study of fiber Bragg gratings with TiN-coated for cryogenic temperature measurement","volume":"136","author":"Hsu","year":"2021","journal-title":"Opt. Laser Technol."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"054404","DOI":"10.1117\/1.OE.52.5.054404","article-title":"Effect of metalizing nickel on the spectrum of fiber Bragg grating","volume":"52","author":"Rao","year":"2013","journal-title":"Opt. Eng."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"4854","DOI":"10.1021\/jacs.7b00279","article-title":"A Study of the Mechanism of the Hydrogen Evolution Reaction on Nickel by Surface Interrogation Scanning Electrochemical Microscopy","volume":"139","author":"Liang","year":"2017","journal-title":"J. Am. Chem. Soc."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1152","DOI":"10.1023\/B:RUEL.0000048647.12787.bb","article-title":"Cathodic hydrogen evolution on nickel in acidic environment","volume":"40","author":"Tamm","year":"2004","journal-title":"Russ. J. Electrochem."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"766","DOI":"10.1016\/j.optcom.2011.10.084","article-title":"Peculiarities of thermo-optic coefficient under different temperature regimes in optical fibers containing fiber Bragg gratings","volume":"285","author":"Adamovsky","year":"2012","journal-title":"Opt. Commun."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1847","DOI":"10.1007\/s00170-015-7609-x","article-title":"A finite element model of thermal evolution in laser micro sintering","volume":"83","author":"Yin","year":"2016","journal-title":"Int. J. Adv. Manuf. Technol."},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Zhang, J., and Korzhavyi, P.A. (2020). First principles investigation on thermodynamic properties and stacking fault energy of paramagnetic nickel at high temperatures. Metals, 10.","DOI":"10.3390\/met10030319"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/19\/7255\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T00:38:54Z","timestamp":1760143134000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/19\/7255"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,9,24]]},"references-count":44,"journal-issue":{"issue":"19","published-online":{"date-parts":[[2022,10]]}},"alternative-id":["s22197255"],"URL":"https:\/\/doi.org\/10.3390\/s22197255","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2022,9,24]]}}}