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Fiber Cavity Ring-Do.n Using an o.tical Time-Do.ain Reflecto.eter

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Pho.o.ic Senso.s 2014年第4期4卷 295-299页

作者： D. J. PASSo. S. o. SILVA J. R. A. FERNANDES M. B. MARQUES o. frazao INESC Po.to Rua do Campo Alegre 687 4169-007 Porto Portugal and Dept. de Fisica e Astronomia da Faculdade deCiOncias da Universidade do Porto Rua do Campo Alegre 687 4169-007 Porto Portugal Departamento.de Fisica Escola de Ci~ncias e Tecnologia Universidade de Tr6s-os-Montes e Alto Douro Quinta dePrados 5001-801 Vila Real Portugal

This wo.k presented a demo.stratio. o. the po.ential fo. a fiber based cavity ring-do.n （CRD） using an o.tical time-do.ain reflecto.eter （o.DR）. The o.DR was used to.send the impulses do.n into.abo.t 20km o. a standard single o.tical fiber, at the end o. which the fiber cavity ring-do.n was placed. The o.DR measured no.appreciable lo.ses, so.o.her CRDs multiplexed co.ld be spliced in parallel alo.g the same o.tical fiber. To.demo.strate the behavio. and sensitivity o. the pro.o.ed co.figuratio., a displacement senso. based o. a fiber taper with a diameter o. 50 μm was placed inside the fiber lo.p, and the induced lo.ses were measured o. the CRD signal -- a sensitivity o. 11.8 ＋ 0.5 μs/mm was achieved. The dynamic range o. the sensing head used in this co.figuratio. was abo.t 2 mm. Finally, this wo.k was also.co.pared with different wo.ks published in the literature.

关键词： o.tical fiber senso.s cavity ring-do.n o.DR

Ammo.ia Sensing System Based o. Wavelength Mo.ulatio. Spectro.co.y

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Pho.o.ic Senso.s 2015年第2期5卷 109-115页

作者： Duarte VIVEIRo. Jo.o.FERREIRA Susana o. SILVA Jo.na RIBEIRo.Deo.inda FLo.ES Jo.e L. SANTo. o.lando.frazao Jo.e M. BAPTISTA INESC Po.to Rua do Campo Alegre 687 4169-007 Porto Portugal Geo.o.y Center o. the University o. Po.to.and Department o. Geo.ciences Environment and Spatial Plannings Facultyof Science at University of Porto Rua do Campo Alegre 687 4169-007 Porto Portugal Department o. Physics and Astro.o.y Faculty of Science at University of Porto Rua do Campo Alegre 687 4169-007 Porto Portugal Co.petence Center o. Exact Sciences and Engineering University of Madeira Campus da Penteada 9000-390 Funchal Portugal

A sensing system in the near infrared regio. has been develo.ed fo. ammo.ia sensing based o. the wavelength mo.ulatio. spectro.co.y （WMS） principle. The WMS is a rather sensitive technique fo. detecting ato.ic/mo.ecular species, presenting the advantage that it can be used in the near-infrared regio. by using the o.tical teleco.municatio.s techno.o.y. In this technique, the laser wavelength and intensity were mo.ulated by applying a sine wave signal thro.gh the injectio. current, which allo.ed the shift o. the detectio. bandwidth to.higher frequencies where laser intensity no.se was typically lo.er. Two.multi-pass cells based o. free space light pro.agatio. with 160 cm and 16 cm o. o.tical path length were used, allo.ing the redundancy o.eratio. and techno.o.y validatio.. This system used a dio.e laser with an emissio. wavelength at 1512.21nm, where NH3 has a stro.g abso.ptio. line. The co.tro. o. the NH3 gas sensing system, as well as acquisitio., pro.essing and data presentatio. was perfo.med.

关键词： Ammo.ia sensing fiber o.tic system near infrared regio. wavelength mo.ulatio. spectro.co.y,enviro.ment

Fiber Fabry-Pero. Interfero.eter fo. Curvature Sensing

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Pho.o.ic Senso.s 2016年第4期6卷 339-344页

作者： Catarina S. Mo.TEIRo. Marta S. FERREIRA Susana o. SILVA Jens Ko.ELKE Kay SCHUSTER Jo.g BIERLICH o.lando.frazao Department o. Physics and Astro.o.y Sciences Faculty Porto University Rua do Campo Alegre 687 4169-007 Porto Portugal INESC-TEC Rua do Campo Alegre 687 4169-007 Porto Portugal IPHT Jena - Leibniz Institute o. Pho.o.ic Techno.o.y Albert-Einstein-Str. 9 07745 Jena Germany

A curvature senso. based o. an Fabry-Pero. （FP） interfero.eter was pro.o.ed. A capillary silica tube was fusio. spliced between two.single mo.e fibers, pro.ucing an FP cavity. Two.FP senso.s with different cavity lengths were develo.ed and subjected to.curvature and temperature. The FP senso. with lo.ger cavity sho.ed three distinct o.erating regio.s fo. the curvature measurement. Namely, a linear respo.se was sho.n fo. an intermediate curvature radius range, presenting a maximum sensitivity o. 68.52 pm/m-1. When subjected to.temperature, the sensing head pro.uced a similar respo.se fo. different curvature radii, with a sensitivity varying fro. 0.84 pm/℃ to.0.89 pm/℃, which resulted in a small cro.s-sensitivity to.temperature when the FP senso. was subjected to.curvature. The FP cavity with sho.ter length presented lo. sensitivity to.curvature.

关键词： Curvature measurement Fabry-Pero. interfero.eter o.tical fiber senso.

Curvature Senso. Based o. a Lo.g-Perio. Grating in a Fiber Ring Reso.ato. Interro.ated by an o.DR

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Pho.o.ic Senso.s 2020年第1期10卷 1-6页

作者： Regina MAGALHAES Susana SILVA o.lando.frazao INESC TEC and Department o. Physics and Astro.o.y Faculty of Sciences of University of PortoPorto 4169-007Portugal

The pro.o.ed technique demo.strates a fiber ring reso.ato. interro.ated by an o.tical time do.ain reflecto.eter(o.DR),fo. intensity *** using this metho.o.o.y,a cavity ro.nd trip time o. 2.85ms was *** a pro.f o. co.cept,a lo.g-perio. grating was inserted in the reso.ant cavity o.erating as a curvature sensing device.A no.el signal pro.essing appro.ch was o.tlined,regarding to.the lo.arithmic behavio. o. the *** analyzing the experimental results,an increase in the measured sensitivities was o.tained by increasing applied *** curvatures perfo.med fro. 1.8 m^(-1) to.4.5 m^(-1),the sensitivity values ranged fro. 2.94 dB·km^(-1) to.5.15 dB·km^(-1).In its turn,the sensitivities o.tained presented a linear behavio. when studied as a functio. o. the applied curvature,fo.lo.ing a slo.e o. 0.86×10-3 *** advantages o. applying this technique were also.discussed,demo.strating two.similar fiber rings multiplexed in a series o. co.figuratio.s.

关键词： Cavity ring-do.n curvature fiber ring reso.ato. lo.g perio. grating o.tical fiber senso.s o.DR

Strain Sensitivity Enhancement in Suspended Co.e Fiber Tapers

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Pho.o.ic Senso.s 2013年第2期3卷 118-123页

作者： Ricardo.M. ANDRE Susana o. SILVA Martin BECKER Kay SCHUSTER M. Ro.HARDT H. BARTELT Manuel B. MARQUES o.lando.frazao INESC Po.to Rua do Campo Alegre 687 4169-007 Porto Portugal Departamento.de Fisica e Astro.o.ia da Faculdade de Ciencias da Universidade do.Po.to Rua do Campo Alegre 687 4169-007 Porto Portugal PHT Institute for Photonic Technology Jena Albert-Einstein-Str. 9 07745 Jena Germany

Suspended co.e fiber tapers with different cro.s sectio.s （with diameters fro. 70μm to.120 μm） are pro.uced by filament heating. Befo.e o.taining the taper, the spectral behavio. o. the suspended co.e fiber is a multimo.e interference structure. When the taper is made, an intermo.al interference between a few mo.es is o.served. This effect is clearly visible fo. lo. taper co.e dimensio.s. Since the co.e and cladding do.no. co.lapse, two.taper regio.s exist, o.e in the co.e and the o.her in the cladding. The cladding taper do.s no. affect the light transmissio., o.ly the co.e is reduced to.a micro.aper. The spectral respo.se o. the micro.aper based-suspended co.e fiber is similar to.a beat o. two.interfero.eters. The strain is applied to.the micro.aper, and with the reductio. in the transverse area, an increase in sensitivity is o.served. When the taper is immersed in a liquid with a different index o. refractio. o. subjected to.temperature variatio.s, no.spectral change o.curs.

关键词： o.tical fiber senso. taper micro.tructured fiber

Center o. Gravity Estimatio. Using a Reactio. Bo.rd Instrumented With Fiber Bragg Gratings

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Pho.o.ic Senso.s 2018年第1期8卷 1-6页

作者： Rui o.IVEIRA Paulo.Ro.IZ Manuel B. MARQUES o.lando.frazao INESC TEC Rua do Campo Alegre 687 4150-179 Porto Portugal CIDESD-ISMAI-Institute University o. Maia (ISMAl) Av. Carlos Oliveira Campos Castelo da Maia 4475-690 MaiaPortugal Department o. Physics and Astro.o.y Faculty of Sciences University of Porto Rua do Campo Alegre 687 4169-007Porto Portugal

The purpo.e o. the present wo.k is to.co.struct a reactio. bo.rd based o. fiber Bragg gratings （FBGs） that co.ld be used fo. estimatio. o. the 2D co.rdinates o. the pro.ectio. o. center o. gravity （CG） o. an o.ject. The apparatus is co.sisted o. a rigid equilateral triangular bo.rd mo.nted o. three suppo.ts at the vertices, two.o. which have cantilevers instrumented with FBGs. When an o.ject o. kno.n weight is placed o. the bo.rd, the bending strain o. the cantilevers is measured by a pro.o.tio.al wavelength shift o. the FBGs. Applying the equilibrium co.ditio.s o. a rigid bo.y and pro.er calibratio. pro.edures, the wavelength shift is used to.estimate the vertical reactio. fo.ces and mo.ents o. fo.ce at the suppo.ts and the co.rdinates o. the o.ject＇s CG pro.ectio. o. the bo.rd. This metho. can be used o. a regular basis to.estimate the CG o. the human bo.y o. o.jects with co.plex geo.etry and density distributio.. An example is pro.ided fo. the estimatio. o. the CG pro.ectio. co.rdinates o. two.o.tho.aedic femur bo.e mo.els, o.e intact, and the o.her with a hip stem implant encased. The clinical implicatio.s o. changing the no.mal CG lo.atio. by means o. a pro.thesis have been discussed.

关键词： o.tical fiber senso.s fiber Bragg gratings cantilever center o. gravity hip pro.thesis

Interfero.eter Based o. a D-shape Chao.ic o.tical Fiber fo. Measurement o. Multiparameters

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Pho.o.ic Senso.s 2012年第4期2卷 381-384页

作者： Susana SILVA Luis Co.LHo.Philippe Ro. o.lando.frazao INESC Po.to Rua do Campo Alegre 687 4169-007 Porto Portugal and Dept. de Fisica e Astronomia da Faculdade de Ciencias da Universiclacle do Porto Rua do Campo Alegre 687 4169-007 Porto Portugal Xlim UMR 6172 CNRS-University o. Limo.es 123 Avenue Albert Thomas 87060 Limoges Cedex France

An interfero.eter based o. a D-shape chao.ic o.tical tiber to. measurement o. multiparameters was pro.o.ed. The sensing structure relied o. a D-shape fiber sectio. spliced in between two.singlemo.e fibers and interro.ated in transmissio.. The o.tical spectrum was co.po.ed by multiple interference lo.s peaks, which were sensitive to.the refractive index, temperature and strain-maximum sensitivities o. 95.2 nm/RIU, 10.5 pm/℃ and -3.51 pm/με, respectively, co.ld be achieved.

关键词： o.tical fiber senso.s interfero.eter chao.ic fiber

Advanced Fiber-o.tic Aco.stic Senso.s

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Pho.o.ic Senso.s 2014年第3期4卷 198-208页

作者： Jo.o.G. V. TEIXEIRA Ivo.T. LEITE Susana SILVA o.lando.frazao EQS Gro.p Rua Joaquim Dias Rocha 354 4470-221 Maia Portugal lNESC TEC (co.rdinated by INESC Po.to. Rua Campo Alegre 687 4169-007 Porto Portugal Department o. Physics and Astro.o.y Faculty of Sciences- University of Porto Rua Campo Alegre 687 4169-007 Porto Portugal

Aco.stic sensing is no.adays a very demanding field which plays an impo.tant ro.e in mo.ern so.iety, with applicatio.s spanning fro. structural health mo.ito.ing to.medical imaging. Fiber-o.tics can bring many advantages to.this field, and fiber-o.tic aco.stic senso.s sho. already perfo.mance levels capable o. co.peting with the standard senso.s based o. piezo.lectric transducers. This review presents the recent advances in the field o. fiber-o.tic dynamic strain sensing, particularly fo. aco.stic detectio.. Three do.inant techno.o.ies are identified - fiber Bragg gratings, interfero.etric Mach-Zehnder, and Fabry-Pero. co.figuratio.s - and their recent develo.ments are summarized.

关键词： Aco.stic senso.s fiber o.tics o.tical fiber senso.s

Temperature-Independent To.sio. Senso. Based o. ＂Figure-o.-Eight＂ Fiber Lo.p Mirro.

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Pho.o.ic Senso.s 2013年第1期3卷 52-56页

作者： Ricardo.M. SILVA António.B. Lo.o.RIBEIRo.o.lando.frazao INESC Po.to Rua do Campo Alegre 687 4169-007 Porto Portugal Departamento de Fisica da Faculdade de Cidnciasda Universidade do Porto Rua do Campo Alegre 687 4169-007 Porto Portugal Faculty o. Health Sciences University Fernando Pessoa R. Carlos da Maia 296 4200-150 Porto Portugal

An interro.atio. senso. system co.bining the ＂figure-o.-eight＂ fiber lo.p mirro. using a single directio.al 3×3 fiber o.tic co.pler was pro.o.ed. o.e fiber lo.p mirro. was fo.med by inserting a length o. high birefringent o.tical fiber at the input po.ts o. the 3×3 co.pler. Splicing the o.tput po.ts o. the 3×3 co.pler between them created the o.her fiber lo.p mirro.. The intro.uctio. o. this seco.d lo.p gave rise to.two.po.arizatio. states o. light with the same frequency but different o.tical phase. The mechanical to.sio. sensing head was lo.ated at the seco.d lo.p and was exhibited an average mo.ulus to.sio. sensitivity o. 7.9×10^-4 degree/dB. The perfo.mance o. the senso. was no. affected by enviro.mental temperature variatio.s. Keywo.ds： To.sio. senso., fiber lo.p mirro., interfero.eter

关键词： To.sio. senso. fiber lo.p mirro. interfero.eter