Cookies Policy
We use cookies to improve our site and your experience. By continuing to browse our site you accept our cookie policy. Find out More
Close
  • Menu
Publications

Publications by CAP

2019

Bi-core optical fiber for sensing o temperature, strain and torsion

Authors
Lobo Ribeiro, ABL; Silva, SFO; Frazao, O; Santos, JL;

Publication
MEASUREMENT SCIENCE AND TECHNOLOGY

Abstract
Bi-core optical fiber structures are studied for applications in sensing. In this paper, an analysis is performed on the spectral characteristics of light propagating in these fibers with central launching core illumination from a standard single mode fiber. Reflective and transmissive configurations are addressed. The characteristics of a reflective bi-core fiber structure for measurement of strain, temperature and absolute value of torsion are investigated and highlights for further research are presented.

2019

Preface

Authors
Lechuga, L; Raptis, I; Jorge, P; Cusano, A;

Publication
Optics and Laser Technology

Abstract

2019

Preface

Authors
Lechuga, L; Raptis, I; Jorge, P; Cusano, A;

Publication
Optics & Laser Technology

Abstract

2019

Preface

Authors
Lechuga, L; Raptis, I; Jorge, P; Cusano, A;

Publication
OPTICS AND LASER TECHNOLOGY

Abstract

2019

High sensitivity strain sensor based on twin hollow microspheres

Authors
Monteiro, CS; Kobelke, J; Schuster, K; Bierlich, J; Silva, SO; Frazao, O;

Publication
MICROWAVE AND OPTICAL TECHNOLOGY LETTERS

Abstract
A sensor based on 2 hollow core microspheres is proposed. Each microsphere was produced separately through fusion splicing and then joined. The resultant structure is a Fabry-Perot interferometer with multiple interferences that can be approximated to a 4-wave interferometer. Strain characterization was attained for a maximum of 1350 mu epsilon, achieving a linear response with a sensitivity of 3.39 +/- 0.04 pm/mu epsilon. The fabrication technique, fast and with no chemical hazards, as opposed to other fabrication techniques, makes the proposed sensor a compelling solution for strain measurements in hash environments.

2019

Multimode Fabry?Perot Interferometer Probe Based on Vernier Effect for Enhanced Temperature Sensing

Authors
Gomes, AD; Becker, M; Dellith, J; Zibaii, MI; Latifi, H; Rothhardt, M; Bartelt, H; Frazao, O;

Publication
Sensors (Basel, Switzerland)

Abstract
New miniaturized sensors for biological and medical applications must be adapted to the measuring environments and they should provide a high measurement resolution to sense small changes. The Vernier effect is an effective way of magnifying the sensitivity of a device, allowing for higher resolution sensing. We applied this concept to the development of a small-size optical fiber Fabry?Perot interferometer probe that presents more than 60-fold higher sensitivity to temperature than the normal Fabry?Perot interferometer without the Vernier effect. This enables the sensor to reach higher temperature resolutions. The silica Fabry?Perot interferometer is created by focused ion beam milling of the end of a tapered multimode fiber. Multiple Fabry?Perot interferometers with shifted frequencies are generated in the cavity due to the presence of multiple modes. The reflection spectrum shows two main components in the Fast Fourier transform that give rise to the Vernier effect. The superposition of these components presents an enhancement of sensitivity to temperature. The same effect is also obtained by monitoring the reflection spectrum node without any filtering. A temperature sensitivity of -654 pm/°C was obtained between 30 °C and 120 °C, with an experimental resolution of 0.14 °C. Stability measurements are also reported.

  • 1
  • 216