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My main work includes developing integrated solutions towards optimization of femto-etching, direct writing and micromachining using femtosecond based mechanisms which will enable the fabrication of the next-generation compact-size, low-power and intelligent sensing devices. In parallel tasks associated with optical fiber sensors fabrication, assembling and testing have been performed, both in lab and field environments.

Interest
Topics
Details

## Details

• #### Name

Carlos Duarte Viveiros
• #### Cluster

Networked Intelligent Systems
• #### Role

Research Assistant
• #### Since

11th February 2013

Portugal
• #### Centre

Applied Photonics
• #### Contacts

+351220402301
carlos.d.viveiros@inesctec.pt
Publications

2019

### Loss Mechanisms of Optical Waveguides Inscribed in Fused Silica by Femtosecond Laser Direct Writing

Authors
Amorim, VA; Maia, JM; Viveiros, D; Marques, PVS;

Publication
Journal of Lightwave Technology

Abstract

2019

### Spectral Tuning of Long Period Fiber Gratings Fabricated by Femtosecond Laser Micromachining through Thermal Annealing

Authors
Viveiros, D; Almeida, JMMMd; Coelho, L; Vasconcelos, H; Amorim, VA; Maia, JM; Jorge, PAS;

Publication
Proceedings

Abstract
A femtosecond laser direct writing system was developed to explore the fabrication of long-period fiber gratings (LPFGs) in SMF28 fibers. The LPFGs, showing the mode LP1,6 at 1500 nm, were exposed to high-temperature annealing up to 950 °C. Modifications in the refractive index (RI) modulation are observed through a blue-shift in the LPFG attenuation bands and above 850 °C, the mode LP1,7 appear at 1600 nm. The wavelength sensitivity to external RI from 1.300 to 1.452 was estimated for both modes before and after annealing. Greater sensitivity was found for the higher order mode in the entire range reaching 2400 nm/RIU around 1.440.

2019

### Spectral characteristics of optical waveguides fabricated in glass by femtosecond laser direct writing

Authors
Amorim, VA; Viveiros, D; Maia, JM; Marques, PVS;

Publication
Proceedings of SPIE - The International Society for Optical Engineering

Abstract
The fabrication of optical waveguides with femtosecond laser direct writing is reported in two materials, Suprasil1 and Eagle2000. The influence of typical fabrication parameters, such as pulse energy and scan velocity, on the waveguide's spectral characteristics is explored from 500 to 1700 nm. Tests conducted in Suprasil1 evidence a strong presence of Rayleigh scattering, hindering the production of low-loss waveguides at short wavelengths. On the other hand, optical waveguides fabricated in Eagle2000 exhibited lower insertion losses at short wavelengths, enabling the fabrication of low-loss broadband optical waveguides with a two order of magnitude higher scan velocity when compared with Suprasil1. © 2019 SPIE.

2019

### Femtosecond laser micromachining of Fabry-Pérot interferometers in fused silica for refractive index sensing

Authors
Maia, JM; Amorim, VA; Viveiros, D; Marques, PVS;

Publication
Proceedings of SPIE - The International Society for Optical Engineering

Abstract
A Fabry-Pérot interferometer was fabricated inside a fused silica substrate through femtosecond laser micromachining. The influence of the waveguide's writing parameters on the measured signal's quality was studied for an interferometer with a 27-µm wide cavity. Optimal signal-to-noise ratio and fringe visibility were obtained for waveguides written at 75 nJ and 50 µm/s. The same device was characterized with different refractive index liquids, and a maximum sensitivity of 1181.4±23.6 nm/RIU was obtained in the index range of 1.2962 to 1.3828 (at 1550 nm) for the spectral order o?'š = 46. © 2019 SPIE.

2019

### Mass Producible Low-Loss Broadband Optical Waveguides in Eagle2000 by Femtosecond Laser Writing

Authors
Amorim, VA; Viveiros, D; Maia, JM; Marques, PVS;

Publication
IEEE PHOTONICS TECHNOLOGY LETTERS

Abstract
Optical waveguides were fabricated in alkaline earth boro-aluminosilicate glass, by femtosecond laser direct writing, with varying pulse energy and scan velocity. A spectral characterization, from 500 nm to 1700 nm, was made in order to determine their losses and understand its dependence on the processing parameters. Three major loss mechanisms were identified. At longer wavelengths, loss is mainly due to weak coupling. On the other hand, the behavior at shorter wavelengths is governed by propagation loss due to Rayleigh scattering, which was shown to be practically eliminated (& x003C; 0.05 dB $\cdot$ cm $<^>{-1} {\cdot }\,\,\mu \text{m}<^>{4}$ ) at higher scan velocities. Bulk absorption was also found to have an influence in the propagation losses at higher wavelengths. The combination of intermediate pulse energies (between 125-250 nJ) and high scan velocities (above 6 cm/s) allowed the fabrication of optical waveguides offering low losses across the entire range of wavelengths tested, facilitating applications that require larger wavelength working bands. Furthermore, since optimal fabrication conditions are achieved at higher scanning velocities, mass production with reduced fabrication times can be achieved.