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Ammonia level sensor using tapered optical fiber coated with titanium dioxide-incorporated porphyrin

Parasuti Frazna, Hikmawati Dyah, Trilaksana Herri, Yasin Moh.

Optica Applicata

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2023

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Vol. 53, nr 3

353--361

EN

Since ammonia is water-soluble, environmental studies have shown that the industrial waste such as fertilizer manufacturing, food products, palm oil, urea fertilizer industry can cause very serious damage to water body ecosystems if not properly managed, resulting in a decrease in water quality. Devices based on optical technology, especially devices that combine optical fibers and nanomaterials, are identified as highly sensitive to the species of interest by detecting changes in physicochemical properties. A practical, easy-to-use, inexpensive instrument for detecting ammonia level was proposed using tapered optical fiber (TOF) coated with titanium dioxide-incorporated porphyrin. TOF was fabricated by simultaneously stretching and heating. The preparation of TiO2/porphyrin/gelatine was prepared to coat tapered optical fiber by dipping. SEM analysis shows an increase in length and a decrease in diameter, also the successful coating of titanium dioxide and porphyrin in the taper region. The EDX analysis also proves the presence of the Ti element in the TOF layer. The TOF produces significant sensing performances toward the ammonia liquid concentration level. The TOF coated with titanium dioxide-incorporated porphyrin can detect a one ppm difference in ammonia concentration with a certain range of output voltage for every concentration has.

2

Investigation of transmission properties of a tapered optical fibre with gold nanoparticles liquid crystal composite cladding

Moś Joanna E., Stasiewicz Karol A., Jaroszewicz Leszek R.

Opto-Electronics Review

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2022

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Vol. 30, No. 4

art. no. e143936

EN

The article presents a study of a hybrid structure based on the combination of a tapered optical fibre and gold nanoparticles dispersed in a liquid crystal material. Sensitivity to changes of the refractive index of the environment in which the structure is located, as well as the possibility of changing the refractive index of liquid crystals by external factors, such as temperature and electric field, were investigated. Electro- and thermally-induced changes of the refractive index of a liquid crystal through the rotation of a molecule director, which cause changes in the light propagated in a tapered optical fibre, were described. The most important issue in the article is to determine the influence of doping a liquid crystal with gold nanoparticles the concentration of which varies between 0.1 and 0.3 wt.%. The paper presents transmission measurements in a wide optical range depending on voltage, temperature, and frequency changes. Additionally, time courses of the obtained signal were measured. The study shows that the appropriate selection of nanoparticle concentration has a huge impact on the optical wave propagation. The experimental results show that the optical changes obtained for the investigated hybrid structure prefer it for use as an electrooptical switcher, filter, or sensor.

3

Simple method for manufacturing and optical characterization of tapered optical fibres

Zakrzewski A., Pięta A., Patela S.

Opto-Electronics Review

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2016

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Vol. 24, No. 4

216--222

EN

Photonic devices often use light delivered by a single-mode telecommunication fibre. However, as the diameter of the core of the optical fibre is of 10 microns, and the transverse dimensions of the photonic waveguides are usually micrometer or less, there is an issue of incompatibility. The problem may be solved by application of tapered optical fibres. For efficient light coupling, the taper should be prepared so as to create a beam of long focal lengt hand small spot diameter in the focus. The article describes the design, fabrication and characterization of tapered optical fibres prepared with a fibre-optic fusion splicer. We modelled the tapers with FDTD method, for estimation of the influence of the tapered length and angle on the spot diameter and the focal length of an outgoing beam. We fabricated tapers from a standard single mode fibre by the Ericsson 995 PM fibre-optic fusion splicer. We planned the splicing technology so as to get the needed features of the beam. We planned a multistep fusion process, with optimized fusion current and fusion time. The experimental measurements of best tapered optical fibres were carried out by the knife-edge method.