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About

About

Gaspar Rego graduated in Physics (Optics and Electronics) by University of Porto (1992). Received the MSc degree in Physics of Laser Communications by University of Essex, Colchester, England (1994). PhD in Engineering Sciences by University of Porto (2006) and Doctor of Science in Physics (“Agregação”) by University of Porto (2013). Currently he is Principal Coordinator Professor ("Full Professor") at the Polytechnic Institute of Viana do Castelo (IPVC), President of the Scientific Council of IPVC and Senior Researcher in the Center of Applied Photonics at INESC TEC. Formerly, he was Vice-President of the Scientific Council of IPVC (4 years), Coordinator of the Electronics and Computer Networks Course (5 years), Coordinator of the Physics Group (15 years), Member of the Scientific Council of ESTG/IPVC (16 years) and Member of the General Council of IPVC (4 years). He co-authored over one-hundred scientific papers in the area of fiber optic componentes and he serves as a reviewer for 17 scientific journals. His current interests are in the areas of fiber optic communications and sensors and also of renewable energy and energetic efficiency.

Interest
Topics
Details

Details

  • Nationality

    Portugal
  • Centre

    Applied Photonics
  • Contacts

    +351220402301
    gaspar.rego@inesctec.pt
Publications

2021

Arc-Induced Long-Period Fiber Gratings at INESC TEC. Part I: Fabrication, Characterization and Mechanisms of Formation

Authors
Rego, G; Caldas, P; Ivanov, OV;

Publication
SENSORS

Abstract
In this work, we reviewed the most important achievements of INESC TEC related to the fabrication of long-period fiber gratings using the electric arc technique. We focused on the fabrication setup, the type of fiber used, and the effect of the fabrication parameters on the gratings' transmission spectra. The theory was presented, as well as a discussion on the mechanisms responsible for the formation of the gratings, supported by the measurement of the temperature reached by the fiber during an electric arc discharge.

2021

Arc-induced long-period fiber gratings at inesc tec. Part ii: Properties and applications in optical communications and sensing

Authors
Rego, G; Caldas, P; Ivanov, OV;

Publication
Sensors

Abstract
In this work, we review the most important achievements of INESC TEC related to the properties and applications of arc-induced long-period fiber gratings. The polarization dependence loss, the spectral behavior at temperatures ranging from cryogenic up to 1200 °C and under exposure to ultraviolet and gamma radiation is described. The dependence of gratings sensitivity on the fabrication parameters is discussed. Several applications in optical communications and sensing domains are referred. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

2021

Simulation of the Transmission Spectrum of Long-Period Fiber Gratings Structures with a Propagating Acoustic Shock Front

Authors
Ivanov, OV; Caldas, P; Rego, G;

Publication
SENSORS

Abstract
In this paper, we investigate modification of transmission spectra of long-period fiber grating structures with an acoustic shock front propagating along the fiber. We simulate transmission through inhomogeneous long-period fiber gratings, pi-shift and reflective pi-shift gratings deformed by an acoustic shock front. Coupled mode equations describing interaction of co-propagating modes in a long-period fiber grating structures with inhomogeneous deformation are used for the simulation. Two types of apodization are considered for the grating modulation amplitude, such as uniform and raised-cosine. We demonstrate how the transmission spectrum is produced by interference between the core and cladding modes coupled at several parts of the gratings having different periods. For the pi-shift long-period fiber grating having split spectral notch, the gap between the two dips becomes several times wider in the grating with the acoustic wave front than the gap in the unstrained grating. The behavior of reflective long-period fiber gratings depends on the magnitude of the phase shift near the reflective surface: an additional dip is formed in the 0-shift grating and the short-wavelength dip disappears in the pi-shift grating.

2021

Optical Fiber Interferometers Based on Arc-Induced Long Period Gratings at INESC TEC

Authors
Caldas, P; Rego, G;

Publication
SENSORS

Abstract
In this work, we review the most important achievements of an INESC TEC long-period-grating-based fiber optic Michelson and Mach-Zehnder configuration modal interferometer with coherence addressing and heterodyne interrogation as a sensing structure for measuring environmental refractive index and temperature. The theory for Long Period Grating (LPG) interferometers and coherence addressing and heterodyne interrogation is presented. To increase the sensitivity to external refractive index and temperature, several LPG interferometers parameters are studied, including order of cladding mode, a reduction of the fiber diameter, different type of fiber, cavity length and the antisymmetric nature of cladding modes.

2016

Arc-Induced Long-Period Fiber Gratings in the Dispersion Turning Points

Authors
Colaco, C; Caldas, P; Del Villar, I; Chibante, R; Rego, G;

Publication
JOURNAL OF LIGHTWAVE TECHNOLOGY

Abstract
We demonstrated the possibility to inscribe long-period fiber gratings (LPFGs) in a B/Ge codoped fiber by using grating periods shorter than 150 mu m. We also have arc-induced in the SMF 28 fiber an LPFG in the dispersion turning points by using a grating period of 197 mu m. In previous works, the shortest periods were, respectively, of the order of 190 and 320 mu m for the same fibers. To achieve such a considerable reduction in the grating periods which enables access to the higher order cladding modes (higher sensitivity), we have developed a high-voltage power supply that allows for a constant and stable electric current ranging from 10.5 up to 21 mA. Computer simulations were used to identify the cladding mode resonances for each grating inscribed in the different fibers. The fabricated LPFGs were characterized as a function of the external refractive index from 1.33 up to 1.42, and an average refractive index sensitivity of -720 nm/RIU in the 1.33-1.41 range was obtained for a 192-mu m LPFG without further optimization, such as the use of etching or thin films deposition.