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About

About

O. Frazão, Graduated in Physics Engineering (optoelectronics and electronics) from the University of Aveiro, Portugal. He received the Ph. D. degree in Physics from the University of Porto, Portugal in 2009. Portugal. From 1997 to 1998, he was with the Institute of Telecommunications, Aveiro. Presently, he is a Researcher at Optoelectronics and Electronic Systems Unit, INESC Porto. He has published about 200 papers, mainly in international journals and conference proceedings, and his present research interests included optical fiber sensors and optical communications. He is member of the Optical Society of America (OSA) and The International Society for Optical Engineering (SPIE).

Interest
Topics
Details

Details

  • Nationality

    Portugal
  • Centre

    Applied Photonics
  • Contacts

    +351220402301
    orlando.frazao@inesctec.pt
013
Publications

2023

Measurement of Paracetamol Concentration Using an Erbium-Doped Fiber Ring Cavity

Authors
Soares, L; Perez Herrera, RA; Novais, S; Ferreira, A; Silva, S; Frazao, O;

Publication
PHOTONICS

Abstract
Process Analytical Technology (PAT) has been increasingly used in the pharmaceutical industry to monitor essential parameters in real-time during pharmaceutical processes. The concentration of Active Pharmaceutical Ingredients (APIs), such as paracetamol, is one of these parameters, and controlling its variations allows for optimization of the production process. In this study, a refractometric sensor, implemented by an interrogation system based on an Erbium-Doped Fiber Ring Cavity (EDFRC), was presented and experimentally demonstrated. The Cavity Ring proposed included a 1 × 3 coupler. One port of the coupler was used to increase the optical power of the system through a Fiber Bragg Grating (FBG), and the other two ports were used as sensing head and reference. The sensor detected variations of paracetamol concentration with a sensitivity of [(-1.00 ± 0.05) × 10-3] nW/(g/kg) and a resolution of 5.53 g/kg. The results demonstrate the potential of this technology as a possible non-invasive PAT tool.

2023

Fiber Loop Mirror Based on Optical Fiber Circulator for Sensing Applications

Authors
Robalinho, P; Soares, B; Lobo, A; Silva, S; Frazao, O;

Publication
SENSORS

Abstract
In this paper, a different Fiber Loop Mirror (FLM) configuration with two circulators is presented. This configuration is demonstrated and characterized for sensing applications. This new design concept was used for strain and torsion discrimination. For strain measurement, the interference fringe displacement has a sensitivity of (0.576 ± 0.009) pm?µe-1. When the FFT (Fast Fourier Transformer) is calculated and the frequency shift and signal amplitude are monitored, the sensitivities are (-2.1 ± 0.3) × 10-4 nm-1 µe-1 and (4.9 ± 0.3) × 10-7 µe-1, respectively. For the characterization in torsion, an FFT peaks variation of (-2.177 ± 0.002) × 10-12 nm-1/° and an amplitude variation of (1.02 ± 0.06) × 10-3/° are achieved. This configuration allows the use of a wide range of fiber lengths and with different refractive indices for controlling the free spectral range (FSR) and achieving refractive index differences, i.e., birefringence, higher than 10-2, which is essential for the development of high sensitivity physical parameter sensors, such as operating on the Vernier effect. Furthermore, this FLM configuration allows the system to be balanced, which is not possible with traditional FLMs.

2022

Sputtering Deposition of TiO2 Thin Film Coatings for Fiber Optic Sensors

Authors
Silva, D; Monteiro, CS; Silva, SO; Frazao, O; Pinto, JV; Raposo, M; Ribeiro, PA; Serio, S;

Publication
PHOTONICS

Abstract
Thin films of titanium dioxide (TiO2) and titanium (Ti) were deposited onto glass and optical fiber supports through DC magnetron sputtering, and their transmission was characterized with regard to their use in optical fiber-based sensors. Deposition parameters such as oxygen partial pressure, working pressure, and sputtering power were optimized to attain films with a high reflectance. The films deposited on glass supports were characterized by UV-Vis spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Regarding the deposition parameters, all three parameters were tested simultaneously, changing the working pressure, the sputtering power, and the oxygen percentage. It was possible to conclude that a lower working pressure and higher applied power lead to films with a higher reflectance. Through the analysis of the as-sputtered thin films using X-ray diffraction, the deposition of both Ti and TiO2 films was confirmed. To study the applicability of TiO2 and Ti in fiber sensing, several thin films were deposited in single mode fibers (SMFs) using the sputtering conditions that revealed the most promising results in the glass supports. The sputtered TiO2 and Ti thin films were used as mirrors to increase the visibility of a low-finesse Fabry–Perot cavity and the possible sensing applications were studied.

2022

Brief Review on Optical Fiber Sensing for the Power Grid

Authors
Rodrigues, AV; Monteiro, C; Silva, SO; Linhares, C; Mendes, H; Tavares, SMO; Frazão, O;

Publication
U.Porto Journal of Engineering

Abstract
In this work, a brief review on the application of fiber optic sensors on power grid apparatus is presented. Power transformers, which are the nodes between electrical transmission lines, are the most expensive, critical and one of the central units of this network. The failure of electrical machines compromises the whole grid leading to power outages and income losses. Thus, constant monitoring of structural health and operating conditions of core infrastructures is sought. With different types of sensors either on the market or in the literature, it is possible to measure physical parameters that make this equipment more reliable.

2022

A Simple Optical Sensor Based on Multimodal Interference Superimposed on Additive Manufacturing for Diameter Measurement

Authors
Cardoso, VHR; Caldas, P; Giraldi, MTR; Fernandes, CS; Frazao, O; Costa, JCWA; Santos, JL;

Publication
SENSORS

Abstract
In many areas, the analysis of a cylindrical structure is necessary, and a form to analyze it is by evaluating the diameter changes. Some areas can be cited: pipelines for oil or gas distribution and radial growth of trees whose diameter changes are directly related to irrigation and the radial expansion since it depends on the water soil deficit. For some species, these radial variations can change in around 5 mm. This paper proposes and experimentally investigates a sensor based on a core diameter mismatch technique for diameter changes measurement. The sensor structure is a combination of a cylindrical piece developed using a 3D printer and a Mach–Zehnder interferometer. The pieces were developed to assist in monitoring the diameter variation. It is formed by splicing an uncoated short section of MMF (Multimode Fiber) between two standard SMFs (Singlemode Fibers) called SMF-MMF-SMF (SMS), where the MMF length is 15 mm. The work is divided into two main parts. Firstly, the sensor was fixed at two points on the first developed piece, and the diameter reduction caused dips or peaks shift of the transmittance spectrum due to curvature and strain influence. The fixation point (FP) distances used are: 5 mm, 10 mm, and 15 mm. Finally, the setup with the best sensitivity was chosen, from first results, to develop another test with an optimization. This optimization is performed in the printed piece where two supports are created so that only the strain influences the sensor. The results showed good sensitivity, reasonable dynamic range, and easy setup reproduction. Therefore, the sensor could be used for diameter variation measurement for proposed applications.

Supervised
thesis

2022

Study and Development of an Interrogation System for Fabry Perot Cavity Sensors

Author
João Manuel Gonçalves Pereira dos Reis

Institution
UP-FEUP

2022

Estudo e desenvolvimento de novas configurações de sensores em fibra ótica para monitorização de cristalizadores na área farmacêutica

Author
Liliana Patrícia Santos Soares

Institution
UP-FEUP

2022

Study and development of optical fiber structures based on graphene

Author
Catarina da Silva Monteiro

Institution
UP-FEUP

2022

Manipulation of polarization through optical devices coated with azobenzenes for applications in communications and sensors

Author
Beatriz Gomes Soares

Institution
UM

2021

Study and development of optical fiber structures based on graphene

Author
Catarina da Silva Monteiro

Institution
UP-FEUP