Publicação
Optical fiber post-processing techniques for sensor applications
| Resumo: | In this work optical fiber post-processing techniques are proposed in order to produce optical fiber sensors (OFS) with lower costs, simplicity and with competitive characteristics compared with their counterparts. The first device was based on multimode interferometers. Those were fabricated by fusing multimode (MM) glass silica fibers (GOF) and MM polymer optical fibers (POF) between two single mode GOFs. For the GOF-based sensor, it was obtained a sensitivity of 4.6 pm/bar. Regarding the POF-based multimodal interferometer, a sensitivity of 58 pm/bar was reached, which corresponds to an enhancement of the sensitivity of twelve times when compared to the one obtained for GOF. Additionally, this sensitivity is five times higher than the one obtained for the POF Bragg grating technology. This improvement in sensitivity makes this sensor very promising since it can reach higher resolutions. The second fiber optic sensor discussed in this work consisted of mechanically induced long period gratings. These were obtained through very simple fabrication methodologies, which consisted of a periodical distribution of photopolymerizable resin onto a single mode GOF, followed by chemical corrosion, which allowed to periodically modulate the fiber diameter. This production method is more advantageous than its direct rivals since it applies cheap and easy to reproduce production techniques and does not require the use of photolithography or chemical vapor deposition technologies. The characterization of this structure to external parameters, such as: longitudinal strain, displacement and temperature revealed promising capabilities, since they allowed, not only the wavelength tuning of the spectral band, but also the optical power coupling strength. The results were very promising, as far as the displacement characterizations are concerned, since a measurement range of 0 - 60 mm was obtained, which is larger than those reported in the literature (i.e. up to 2 mm). |
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| Autores principais: | Valente, Nuno Fonseca |
| Assunto: | Optical fiber sensors Multimodal interferometers Long period gratings Hydrostatic pressure Strain Displacement Temperature Spectral filters |
| Ano: | 2023 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Aveiro |
| Idioma: | inglês |
| Origem: | RIA - Repositório Institucional da Universidade de Aveiro |
| Resumo: | In this work optical fiber post-processing techniques are proposed in order to produce optical fiber sensors (OFS) with lower costs, simplicity and with competitive characteristics compared with their counterparts. The first device was based on multimode interferometers. Those were fabricated by fusing multimode (MM) glass silica fibers (GOF) and MM polymer optical fibers (POF) between two single mode GOFs. For the GOF-based sensor, it was obtained a sensitivity of 4.6 pm/bar. Regarding the POF-based multimodal interferometer, a sensitivity of 58 pm/bar was reached, which corresponds to an enhancement of the sensitivity of twelve times when compared to the one obtained for GOF. Additionally, this sensitivity is five times higher than the one obtained for the POF Bragg grating technology. This improvement in sensitivity makes this sensor very promising since it can reach higher resolutions. The second fiber optic sensor discussed in this work consisted of mechanically induced long period gratings. These were obtained through very simple fabrication methodologies, which consisted of a periodical distribution of photopolymerizable resin onto a single mode GOF, followed by chemical corrosion, which allowed to periodically modulate the fiber diameter. This production method is more advantageous than its direct rivals since it applies cheap and easy to reproduce production techniques and does not require the use of photolithography or chemical vapor deposition technologies. The characterization of this structure to external parameters, such as: longitudinal strain, displacement and temperature revealed promising capabilities, since they allowed, not only the wavelength tuning of the spectral band, but also the optical power coupling strength. The results were very promising, as far as the displacement characterizations are concerned, since a measurement range of 0 - 60 mm was obtained, which is larger than those reported in the literature (i.e. up to 2 mm). |
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