Fibre optic sensors are used to measure various physical quantities, including polarisation plane rotation. Existing solutions for measuring the rotation of the plane of polarisation in optical fibres are based on sensors using tilted fibre Bragg gratings (TFBGs). Articles describing the...

This paper introduces a new method for designing inverted gradient multilayer optical fibres to generate flat-top laser beams with specific propagation features. Using numerical simulations in OptiFibre software, over 700 three-layer optical fibre configurations were modelled, and their output beam profiles were assessed based on beam flatness, edge steepness, and full width at half maximum (FWHM). A unique set of parameters describing the refractive index profile was proposed to improve the estimation of beam properties. The random forest algorithm was employed to predict beam characteristics based on fibre geometry, and a feature importance analysis identified key parameters that influence these characteristics. The model showed high prediction accuracy, particularly when the proposed descriptors were combined with layer refractive indices. Additionally, two multi-criteria optimisation methods – trade-off and weighted objectives – were used to find optimal fibre configurations that simultaneously maximise beam flatness, edge steepness, and FWHM. The findings offer practical guidelines for the inverse design of beam-shaping optical fibres and demonstrate the potential of machine learning to accelerate fibre design by reducing dependence on lengthy simulations.

This article presents a method for inverse design of multiring optical fibres using machine learning. It proposes fibre configurations expected to yield specified beam-shaping parameters and verifies selected off-grid configurations using independent OptiFiber simulations. The proposed method...

Tilted fibre Bragg gratings (TFBG) are used as sensors in the measurement of many physical and chemical quantities. Measurement is performed indirectly by analysing the power of light transmitted at a specific wavelength or in a selected range of light wavelengths. The wavelengths to be used are...

This paper presents the results of studies on the synthesis of nitrogen oxides (NOx) in a three-phase GlidArc plasma reactor operating at atmospheric pressure. The objective was to determine the influence of electrical power and gas flow rate on NOx concentration, process productivity, and energy efficiency. The analysis was performed over a wide range of power levels and air flow rates, using global energy efficiency (GEE), specific energy consumption (E), and specific energy input (SEI) as evaluation metrics. The results demonstrate that discharge intensification initially leads to an increase in NOx concentration; however, at higher power levels a deterioration of energy efficiency is observed due to increasing thermal losses and partial destruction of nitrogen oxides. Gas flow rate was also found to play a significant role by determining the gas residence time in the plasma zone and the degree of reactant conversion. Based on the analysis of the median GEE and E maps, a recommended operating window for the reactor was identified, within which high energy efficiency and high NOx productivity are simultaneously achieved. The obtained results provide a basis for further optimization and scaling of GlidArc technology in the context of decentralized nitrogen compound production.