The different topics of this thesis include high-temperaturestable fiber Bragg gratings, photosensitivity and fiber basedcomponents. Fiber Bragg gratings (FBG) are wavelength dispersiverefractive index structures manufactured through UV exposure ofoptical fibers. Their applications range from WDM filters,dispersion compensators and fiber laser resonators fortelecommunication applications to different types of point ordistributed sensors for a variety of applications. One aim of this thesis has been to study a new type of FBGreferred to as chemical composition grating. These gratingsdiffer from other types of FBG in that their refractive indexstructure is attributed to a change in the chemicalcomposition. Chemical composition gratings have shown to beextremely temperature stable surviving temperatures in excessof 1000 oC. Photosensitivity of pure silica and germanium-dopedcore fibers in the presence of hydroxyl groups has also beenstudied and different types of fiber based components have beendeveloped. The main result of the thesis is a better understanding ofthe underlying mechanism of the formation of chemicalcomposition gratings and their decay behavior at elevatedtemperatures. The refractive index modulation is caused by aperiodic change in the fluorine concentration, which has beenverified through time-of-flight secondary-ion-mass spectrometryand through studies of the decay behavior of chemicalcomposition gratings. A model based on diffusion of dopants hasbeen developed, which successfully predicts the thermal decayat elevated temperatures. Studies of the dynamics of chemicalcomposition grating formation have resulted in a manufacturingtechnique that allows for reproducible gratingfabrication. The main results regarding photosensitivity is a method tosignificantly increase the effect of UV radiation on standardtelecommunications fiber. The method, referred to asOH-flooding, has also been applied to pure-silica core fibersresulting in the first report of strong grating formation insuch fibers. Finally, research into different schemes for developingfiber-based components has resulted in two types of singlefiber integrated Mach-Zehnder interferometers; one passiveinterferometer that can be used as an optical filter and oneactive interferometer controlled with internal metalelectrodes. Keywords:optical fibers, fiber Bragg gratings,photosensitivity, thermal stability, fiber sensors, chemicalcomposition gratings, fiber components, Mach-Zehnderinterferometer, optical switch, optical modulator. / QC 20100607

This thesis describes research on near degenerate quasi phase-matched opticalparametric oscillators (OPO) where volume Bragg gratings (VBG) are used toproduce narrow oscillation bandwidth. These OPOs are then used to pump a secondOPO to generate mid-infrared radiation. The atmospheric transmission windows in the 3.5 to 5 μm wavelength region areused for seekers on infrared homing missiles. These missiles are available to guerrillaand terrorist groups and have been used in a number of attacks on military and civilianaircraft. Laser sources at the same wavelengths are an important component incountermeasure systems for aircraft self-protection. Similar laser sources also haveapplications in laser surgery. At wavelengths longer than 4 μm crystal materials for multi-Watt level averagepower nonlinear devices is a problem. The best solution so far is to use ZnGeP2(ZGP). ZGP and the available alternatives all have a problem of near-infraredabsorption, and a mid-infrared OPO thus has to use a pump wavelength near 2 μm.This pump source can be a neodymium laser at 1.06 μm with a near degenerate OPO. Nonlinear devices for low to medium pulse energies are dominated by quasi phasematchedmaterials because of their higher effective nonlinearities and lack of walkoff.In addition they allow type I interaction where signal and idler from the OPOhave the same polarization, which has the advantage that both waves can be used topump the ZGP OPO. The drawback of this is that the near-degenerate interaction hasvery wide gain bandwidth. Efficient pumping of the second OPO demands narrowbandwidth output from the first OPO.Volume Bragg gratings that are glass materials with a periodic refractive indexmodulation have emerged as high quality narrow bandwidth reflectors. By using aVBG as one cavity mirror in an OPO the feedback bandwidth and hence the OPOoscillation bandwidth can be kept very narrow. Signal and idler bandwidths of 10 and20 GHz (FWHM) at 2122 and 2135 nm, respectively, have been demonstrated. Thisshould be compared to the several hundred nanometre bandwidth from an OPO usingdielectric mirrors. Very narrow bandwidth operation has been achieved so close todegeneracy that the signal and idler are not resolvable. The total output energy generated in the PPKTP OPO (signal and idler together)has been used to pump a ZGP OPO that produced mid-IR radiation. Tuning of thesignal from a ZGP OPO from 2.9 μm to degeneracy at 4.3 μm has been shown, with acorresponding idler wavelength tuneable up to 8 μm. The highest conversionefficiency that has been reached from 1.06 μm to the mid-IR was 12 %. This setupused a PPKTP OPO with 30 % conversion efficiency and 13 nm separation of signaland idler (2122 and 2135 nm). The pulse repetition frequency was 20 kHz and thegenerated output power in the mid-IR was 3.2 W. / QC 20100517

Fiber Bragg gratings (FBGs) are key elements in modern telecommunication and sensing applications. In optical communication, with the advancement of the Erbium doped fiber amplifier (EDFA), there is a great demand for devices with wavelength tunability over the Erbium gain bandwidth (in particular, for wavelength division multiplexing (WDM) networks). The center wavelength of a FBG can be shifted by means of change of temperature, pressure or mechanical axial strain. The axial strain approach is the best method among all other techniques because it allows relatively large wavelength shifts with high speed. Axial strain of up to 4% will be required to cover the whole EDFA region (more than 40 nm of central wavelength shift). The formation of Bragg grating results in significant reduction in mechanical strength of optical fibers especially in tension. As a result, axial strain of only about 1% can be achieved by mechanical stretching of FBGs. In order to achieve the remaining 3% strain compression of FBGs has to be applied. In this thesis, the design and analysis of a novel device for achieving central wavelength shift are presented. In particular, the device has achieved, for a fiber with 12 mm FBG, a shifting of 46 nm in compression and 10.5 nm in tension with a reflection power loss of less than 0.25 dB and a FWHM bandwidth variation of approximately 0.1 nm. Both variations are well below the Bellcore standards requirement of 0.5 dB for peak reflectivity variation and 0.1 nm for bandwidth variation. The device consists of two fixed and one guiding ferrules. The difficulties associated with compressing the FBG were handled by carefully selecting tolerances and adjustment procedures. The device allows both tension and compression of FBGs, and the use of different FBG lengths and actuators. The effects of glue deformation and bending of the FBG during compression were analyzed in detail. Further, using the piezoelectric transducer (PZT) actuator as a driver, tuning speed of around 1.5nm/ms was achieved.

The focus of this thesis is on the development of sensing devices based on optical fiber sensors, specifically optical Fiber Bragg Gratings (FBG), using laser microfabrication methods. FBG is a type of optical fibers whose spectral response is affected by applied strain and temperature. As a result, it can be calibrated for the measurement of physical parameters manifesting themselves in the changes of strain or temperature. The unique features of optical fiber sensors such as FBGs have encouraged the widespread use of the sensor and the development of optical fiber-based sensing devices for structural measurements, failure diagnostics, thermal measurements, pressure monitoring, etc. These features include light weight, small size, long-term durability, robustness to electromagnetic disturbances, and resistance to corrosion. Despite the encouraging features, there are some limitations and challenges associated with FBGs and their applications. One of the challenges associated with FBGs is the coupling of the effects of strain and temperature in the optical response of the sensors which affects the reliability and accuracy of the measurements. Another limitation of FBGs is insensitivity to the index of refraction of their surrounding medium. In liquids, the index of refraction is a function of concentration. Making FBGs sensitive to the index of refraction and keeping their thermal sensitivity intact enable optical sensors with the capability of the simultaneous measurement of concentration and temperature in liquids. Considering the unique features of FBGs, embedding of the sensors in metal parts for in-situ load monitoring is a cutting-edge research topic. Several industries such as machining tools, aerospace, and automotive industries can benefit from this technology. The metal embedding process is a challenging task, as the thermal decay of UV-written gratings can starts at a temperature of ~200 oC and accelerates at higher temperatures. As a result, the embedding process needs to be performed at low temperatures. The objective of the current thesis is to move forward the existing research front in the area of optical fiber sensors by finding effective solutions to the aforementioned limitations. The approaches consist of modeling, design, and fabrication of new FBG-based sensing devices. State-of-the-art laser microfabrication methods are proposed and implemented for the fabrication of the devices. Two approaches are adopted for the development of the FBG-based sensing devices: the additive method and the subtractive method. In both methods, laser direct microfabrication techniques are utilized. The additive method deals with the deposition of on-fiber metal thin films, and the subtractive method is based on the selective removal of materials from the periphery of optical fibers. To design the sensing devices and analyze the performance of the sensors, an opto-mechanical model of FBGs for thermal and structural monitoring is developed. The model is derived from the photo-elastic and thermo-optic properties of optical fibers. The developed model can be applied to predict the optical responses of a FBG exposed to structural loads and temperature variations with uniform and non-uniform distributions. The model is also extended to obtain optical responses of superstructure FBGs in which a secondary periodicity is induced in the index of refraction along the optical fiber. To address the temperature-strain coupling in FBGs, Superstructure FBGs (SFBG) with on-fiber metal thin films are designed and fabricated. It is shown that SFBGs have the capability of measuring strain and temperature simultaneously. The design of the sensor with on-fiber thin films is carried out by using the developed opto-mechanical model of FBGs. The performance of the sensor in concurrent measurement of strain and temperature is investigated by using a customized test rig. A laser-based Direct Write (DW) method, called Laser-Assisted Maskless Microdeposition (LAMM), is implemented to selectively deposit silver thin films on optical fibers and fabricate the superstructure FBGs. To attain thin films with premium quality, a characterization scheme is designed to study the geometrical, mechanical, and microstructural properties of the thin films in terms of the LAMM process parameters. A FBG, capable of measuring concentration and temperature of liquids is developed, and its performance is tested. Femtosecond laser micromachining is successfully implemented as a subtractive method for the sensor fabrication. For this purpose, periodic micro-grooves are inscribed in the cladding of regular FBGs so as to increase their sensitivity to the concentration of their surrounding liquid while keeping their thermal sensitivity intact. This type of sensors has the potential for applications in biomedical research, in which the in-situ measurement of the properties of biological analytes is required. Another accomplishment of this thesis is the development of FBG sensors embedded in metal parts for structural health monitoring using low temperature embedding processes. In this regard, the opto-mechanical model is extended to predict the optical response of the embedded FBGs. The embedding process involves low temperature casting, on-fiber thin film deposition, and electroplating methods. The performance of the embedded sensors is evaluated in structural loading and thermal cycling.

The focus of this thesis is on the development of sensing devices based on optical fiber sensors, specifically optical Fiber Bragg Gratings (FBG), using laser microfabrication methods. FBG is a type of optical fibers whose spectral response is affected by applied strain and temperature. As a result, it can be calibrated for the measurement of physical parameters manifesting themselves in the changes of strain or temperature. The unique features of optical fiber sensors such as FBGs have encouraged the widespread use of the sensor and the development of optical fiber-based sensing devices for structural measurements, failure diagnostics, thermal measurements, pressure monitoring, etc. These features include light weight, small size, long-term durability, robustness to electromagnetic disturbances, and resistance to corrosion. Despite the encouraging features, there are some limitations and challenges associated with FBGs and their applications. One of the challenges associated with FBGs is the coupling of the effects of strain and temperature in the optical response of the sensors which affects the reliability and accuracy of the measurements. Another limitation of FBGs is insensitivity to the index of refraction of their surrounding medium. In liquids, the index of refraction is a function of concentration. Making FBGs sensitive to the index of refraction and keeping their thermal sensitivity intact enable optical sensors with the capability of the simultaneous measurement of concentration and temperature in liquids. Considering the unique features of FBGs, embedding of the sensors in metal parts for in-situ load monitoring is a cutting-edge research topic. Several industries such as machining tools, aerospace, and automotive industries can benefit from this technology. The metal embedding process is a challenging task, as the thermal decay of UV-written gratings can starts at a temperature of ~200 oC and accelerates at higher temperatures. As a result, the embedding process needs to be performed at low temperatures. The objective of the current thesis is to move forward the existing research front in the area of optical fiber sensors by finding effective solutions to the aforementioned limitations. The approaches consist of modeling, design, and fabrication of new FBG-based sensing devices. State-of-the-art laser microfabrication methods are proposed and implemented for the fabrication of the devices. Two approaches are adopted for the development of the FBG-based sensing devices: the additive method and the subtractive method. In both methods, laser direct microfabrication techniques are utilized. The additive method deals with the deposition of on-fiber metal thin films, and the subtractive method is based on the selective removal of materials from the periphery of optical fibers. To design the sensing devices and analyze the performance of the sensors, an opto-mechanical model of FBGs for thermal and structural monitoring is developed. The model is derived from the photo-elastic and thermo-optic properties of optical fibers. The developed model can be applied to predict the optical responses of a FBG exposed to structural loads and temperature variations with uniform and non-uniform distributions. The model is also extended to obtain optical responses of superstructure FBGs in which a secondary periodicity is induced in the index of refraction along the optical fiber. To address the temperature-strain coupling in FBGs, Superstructure FBGs (SFBG) with on-fiber metal thin films are designed and fabricated. It is shown that SFBGs have the capability of measuring strain and temperature simultaneously. The design of the sensor with on-fiber thin films is carried out by using the developed opto-mechanical model of FBGs. The performance of the sensor in concurrent measurement of strain and temperature is investigated by using a customized test rig. A laser-based Direct Write (DW) method, called Laser-Assisted Maskless Microdeposition (LAMM), is implemented to selectively deposit silver thin films on optical fibers and fabricate the superstructure FBGs. To attain thin films with premium quality, a characterization scheme is designed to study the geometrical, mechanical, and microstructural properties of the thin films in terms of the LAMM process parameters. A FBG, capable of measuring concentration and temperature of liquids is developed, and its performance is tested. Femtosecond laser micromachining is successfully implemented as a subtractive method for the sensor fabrication. For this purpose, periodic micro-grooves are inscribed in the cladding of regular FBGs so as to increase their sensitivity to the concentration of their surrounding liquid while keeping their thermal sensitivity intact. This type of sensors has the potential for applications in biomedical research, in which the in-situ measurement of the properties of biological analytes is required. Another accomplishment of this thesis is the development of FBG sensors embedded in metal parts for structural health monitoring using low temperature embedding processes. In this regard, the opto-mechanical model is extended to predict the optical response of the embedded FBGs. The embedding process involves low temperature casting, on-fiber thin film deposition, and electroplating methods. The performance of the embedded sensors is evaluated in structural loading and thermal cycling.

Fiber Bragg gratings (FBGs) are key elements in modern telecommunication and sensing applications. In optical communication, with the advancement of the Erbium doped fiber amplifier (EDFA), there is a great demand for devices with wavelength tunability over the Erbium gain bandwidth (in particular, for wavelength division multiplexing (WDM) networks). The center wavelength of a FBG can be shifted by means of change of temperature, pressure or mechanical axial strain. The axial strain approach is the best method among all other techniques because it allows relatively large wavelength shifts with high speed. Axial strain of up to 4% will be required to cover the whole EDFA region (more than 40 nm of central wavelength shift). The formation of Bragg grating results in significant reduction in mechanical strength of optical fibers especially in tension. As a result, axial strain of only about 1% can be achieved by mechanical stretching of FBGs. In order to achieve the remaining 3% strain compression of FBGs has to be applied. In this thesis, the design and analysis of a novel device for achieving central wavelength shift are presented. In particular, the device has achieved, for a fiber with 12 mm FBG, a shifting of 46 nm in compression and 10.5 nm in tension with a reflection power loss of less than 0.25 dB and a FWHM bandwidth variation of approximately 0.1 nm. Both variations are well below the Bellcore standards requirement of 0.5 dB for peak reflectivity variation and 0.1 nm for bandwidth variation. The device consists of two fixed and one guiding ferrules. The difficulties associated with compressing the FBG were handled by carefully selecting tolerances and adjustment procedures. The device allows both tension and compression of FBGs, and the use of different FBG lengths and actuators. The effects of glue deformation and bending of the FBG during compression were analyzed in detail. Further, using the piezoelectric transducer (PZT) actuator as a driver, tuning speed of around 1.5nm/ms was achieved.

The main topic of this thesis work is photosensitivity and photo-structuring of optical fibers and bulk glass. Although research in the field of photosensitivity in glass and optical fibers has been ongoing for more than three decades, the underlying mechanisms are still not well understood. The objective was to gain a better understanding of the photo-response by studying photosensitivity from a thermodynamic perspective, as opposed to established research focusing on point defects and structural changes, and strain and stress in optical fibers. Optical fibers was mainly used for experimental studies for two reasons; first, photosensitivity in fibers is more pronounced and more elusive compared to its bulk counterpart, and secondly, fibers provide a simplified structure to study as they experimentally can be seen as one-dimensional.Initially, ablation experiments on bulk glass were performed using picosecond infrared pulses. With a design cross section of 40x40 μm, straight channels were fabricated on the top (facing incident light) and bottom side of the sample and the resulting geometries were analyzed. The results show a higher sensitivity to experimental parameters for bottom side ablation which was ascribed to material incubation effects. Moreover, on the top side, the resulting geometry has a V-shape, independent of experimental parameters, related to the numerical aperture of the focusing lens, which was ascribed to shadowing effects.After this work, the focus shifted towards optical fibers, UV-induced fiber Bragg gratings (FBGs) and thermal processing with conventional oven and with a CO2 laser as a source of radiant heat.First, a system for CO2 laser heating of optical fibers was constructed. For measuring the temperature of the processed fibers, a special type of FBG with high temperature stability, referred to as "Chemical Composition Grating" (CCG) was used. A thorough characterization and temperature calibration was performed and the results show the temperature dynamics with a temporal resolution of less than one millisecond. The temperature profile of the fiber and the laser beam intensity profile could be measured with a spatial resolution limited by the grating length and diameter of the fiber. Temperatures as high as ~ 1750 °C could be measured with corresponding heating and cooling rates of 10.500 K/s and 6.500 K/s.Subsequently, a thorough investigation of annealing and thermal regeneration of FBGs in standard telecommunication fibers was performed. The results show that thermal grating regeneration involves several mechanisms. For strong regeneration, an optimum annealing temperature near 900 C was found. Two different activation energies could be extracted from an Arrhenius of index modulation and Braggv iwavelength, having a crossing point also around 900 °C, indication a balance of two opposing mechanisms.Finally, the thermal dynamics and spectral evolution during formation of long period fiber gratings (LPGs) were investigated. The gratings were fabricated using the CO2 laser system by periodically grooving the fibers by thermal ablation. Transmission losses were reduced by carefully selecting the proper processing conditions. These parameters were identified by mapping groove depth and transmission loss to laser intensity and exposure time. / Huvudtemana i denna avhandling är fotokänslighet och fotostrukturering av optiska fibrer och bulk glas. Trots att forskning inom fotokänslighet i glas och optiska fibrer har pågått under mer än tre decennier är de bakomliggande mekanismerna ännu inte klarlagda. Syftet var att få en bättre förståelse för fotoresponsen genom att studera fotokäsligheten ur ett termodynamiskt perspektiv, i motsats till etablerad forskning med fokus på punktdefekter och strukturförändringar, samt mekaniska spännings effekter i optiska fibrer. Optiska fibrer användes för flertalet av de experimentella studierna av två skäl; för det första är fotokänsligheten i fibrer större och dessutom vet man mindre om bakomliggande mekanismer jämfört med motsvarande bulk glas, och för det andra kan fibrer vara enklare att studera eftersom de experimentellt kan ses som en endimensionell struktur.Inledningsvis utfördes ablaherings experiment på bulk glas med en infraröd laser med pikosekund pulser. Raka kanaler med ett designtvärsnitt på 40x40 μm tillverkades på ovansidan (mot infallande ljus) och bottensidan av provet och de resulterande geometrierna analyserades. Resultaten visar en högre känslighet för variationer i experimentella parametrar vid ablahering på undersidan vilket kan förklaras av inkubations effekter i materialet. Dessutom är den resulterande geometrin på ovansidan V-formad, oavsett experimentella parametrar, vilket kunde relateras till den numeriska aperturen hos den fokuserande linsen, vilket förklaras av skuggningseffekter.Efter detta arbete flyttades fokus mot optiska fibrer, UV inducerade fiber Bragg gitter (FBG), och termisk bearbetning med konventionell ugn samt även med en CO2-laser som källa för strålningsvärme.Först konstruerades ett system för CO2-laservärmning av fibrer. För mätning av temperaturen hos bearbetade fibrer användes en speciell sorts FBG med hög temperaturstabilitet, kallade ”Chemical Composition Gratings” (CCG). En grundlig karaktärisering och temperaturkalibrering utfördes och temperaturdynamiken mättes med en tidsupplösning på under en millisekund. Temperaturprofilen i fibern, och laserns strålprofil, kunde mätas med en spatiell upplösning begränsad av gitterlängden och fiberns diameter. Temperaturer upp till ~1750 °C, vilket är högre än mjukpunktstemperaturen, kunde mätas med korresponderande uppvärmnings- och avsvalningshastighet på 10.500 K/s och 6.500 K/s.Därefter gjordes en omfattande undersökning av värmebearbetning och termisk regenerering av FBG:er i telekomfiber. Resultaten visar att termisk gitter-regenerering aktiveras av flera olika mekanismer. Värmebearbetning vid en temperatur omkring 900 °C resulterade i starka gitter efter en regenerering vid en temperatur på 1100 °C. Två olika aktiveringsenergier kunde extraheras från en Arrhenius plot avseende brytningsindexmodulation och Braggvåglängd, med en skärningspunkt tillika runt 900 °C, vilket indikerar en avvägning mellan två motverkande mekanismer vid denna temperatur.Slutligen undersöktes temperaturdynamiken och de spektrala egenskaperna under tillverkning av långperiodiga fibergitter (LPG). Gittren tillverkades med CO2-vi iilasersystemet genom att skapa en periodisk urgröpning medelst termisk ablahering. Transmissionsförluster kunde reduceras med noggrant valda processparametrar. Dessa parametrar identifierades genom mätningar av ablaherat djup och transmissionsförlust som funktion av laserintensitet och exponeringstid. / <p>QC 20150924</p>

A novel nano-structure is proposed to enhance extraordinary optical transmission from a periodic array of nano-holes. The Plasmonic Bragg reflector works by recapturing surface plasmons that are scattered off the edge of the array during the extraordinary optical transmission process, and reflecting them back towards the array where they can interfere with the light and enhance transmission. This reduces losses from a subwavelength aperture array. The reflectors are positioned to reflect in-phase with the light transmission. Polarization sensitivity of the plasmonic Bragg reflector is demonstrated. Modulation of the transmission is achieved by varying the separation between the array and reflectors. Isolation of adjacent structures on a plasmonic device by the use of the Bragg reflectors is attempted. Transmission and diffraction properties of quasiperiodic nano-hole arrays in a gold film are studied. Resonant transmission is observed, whose values do not simply match surface plasmon wave-vector values. Rotationally symmetric diffraction from the quasicrystal nano-hole array. This diffraction is seen to be controllable by the polarization of the excitation laser. Finite difference time domain calculations of the quasiperiodic array are performed to better understand the origin of the observed transmission resonances. Good agreement between theory and experiment is observed. Calculations show the formation of near-field hot-spots over the structure.

[pt] O objetivo deste trabalho foi o desenvolvimento de um sistema de medição de deformações utilizando redes de Bragg em fibras ópticas. Experiências preliminares empregando um analisador de espectro óptico comprovaram que a relação entre deformação e translação espectral do sinal refletido pelo sensor é linear. Baseado neste princípio, foi proposto um circuito óptico para a demodulação do sinal. Este circuito, de construção simples e barata, utiliza uma rede de Bragg como sensor e outra, com largura espectral bem maior, como filtro óptico. Dois fotodetectores são responsáveis pela recepção do sinal e por tornar o sistema auto-compensável. Dois métodos de calibração do sistema, um numérico e outro experimental, são apresentados e testados. A partir dos resultados das experiências, sugestões são feitas no sentido de melhorar os métodos de calibração. A automatização das calibrações e medições é proposta e um método de separação de efeitos de temperatura e deformação mecânica é apresentado. / [en] The goal of the present work has been to develop a fiber Bragg grating strain sensor system. Experiments with an optical spectrum analyzer have confirmed that there is a linear relationship between the strain in the gratting and the shift of the central wave length reflected by the sensor. Based on this measurement principle, a simple and inexpensive optical circuit for demodulation of the sensor s reflected signal has been developed. Two photodetectors are employed in order to reduce the influence of power fluctuations of the optical source as well as of other losses. The measurement system has been calibrated both numerically and experimentally with satisfactory agreement. Suggestions are made in order to improve the calibration techniques, and a method for decoupling the temperature effects from the strain measurement is proposed.

[pt] Sensores magnéticos são sensores que detectam o fluxo devido a campos magnéticos que existem na região do espaço delimitada pela geometria do sensor. Cada tipo de sensor possui propriedades únicas que os tornam mais para aplicações particulares, seja na detecção de campos magnéticos estáticos ou variáveis. Esta tese desenvolveu sensores de campo magnético utilizando materiais magnéticos e fibras ópticas com redes de Bragg (FBG). Foram desenvolvidos neste trabalho protótipos de sensores que são simples na sua construção, leves e compactos, facilitando sua utilização em lugares de difícil acesso como, por exemplo, para o monitoramento do campo magnético em locais remotos. Dois tipos de sensores foram são desenvolvidos: o primeiro consiste em materiais magnetostrictivos no formato maciço e compósito, que possuem a propriedade de se deformarem na presença de um campo magnético externo. Esta deformação no material é detectada com redes de Bragg. É explorada a resposta do sensor quando este é imerso em campos magnéticos uniformes e gradientes de campo; o segundo sensor consiste em um ímã permanente de geometria cilíndrica fabricado com um furo central no qual uma fibra óptica contendo uma rede de Bragg pode ser inserida e colada. Quando o sensor interage com um material ferromagnético, a força magnética atrativa entre eles é transferida de forma axial para a FBG produzindo uma variação no comprimento de onda refletido. O sensor baseado em materiais magnetostrictivos funciona para de campos magnéticos da ordem do militesla. Já o sensor de força magnética necessita de um gradiente de campo para funcionar. Com este sensor é possível a obtenção de imagens produzidas por áreas de corrosão em materiais ferromagnéticos. Em ambos os casos, a sensibilidade com relação à variação da geometria do sensor é estudada. / [en] Magnetic sensors detect the flux generated by magnetic fields which exists in the region of space delimited by the geometry of the sensor. Each kind of sensor has a unique property that makes it more appropriate for particular applications. In this thesis we have built magnetic field sensors using magnetic materials and fiber Bragg gratings (FBG). We have focused on prototypes simple to construct, light and compact, making it easy to measure magnetic fields in remote places. Two kinds of sensors were built: the first one consists of magnetostrictive materials in bulk shape and in composite format. They have the property of increase their size in the presence of an external magnetic field. The deformation in the material is detected by using a single FBG. The sensor sensitivity is analyzed when it is immersed in uniform magnetic fields and field gradients. The second sensor consists of a magnet fabricated with a central hole in which a fiber optics containing a FBG can be attached. When the sensor interacts with a ferromagnetic material, the attractive magnetic force between them is transferred to the FBG, producing variation in the reflected wavelength. The sensor based in magnetostrictive materials works for magnetic fields at the militesla range. The magnetic force sensor needs a gradient field to work. Using the force sensor, it was possible to image corrosion areas in ferromagnetic materials. In both cases, the sensitivity with regard to the sensor geometry was studied.