The present paper discusses polarization phenomena occurring in microstructrured liquid crystal fibers and in particular solid-core photonic crystal fibers infiltrated with liquid crystals. We report on the latest experimental polarization characteristics of microstructured photonic crystal fibers filled with prototype nematic liquid crystal guest materials characterized by either extremely low (of the order ∼ 0.05) or medium (of the order ∼ 0.2) material birefringence. Due to anisotropic properties of the microstructrured liquid crystal fibers switching between different guiding mechanisms as well as electrically and temperature-induced tuning of light propagation have been demonstrated. These preliminary results hold great potential for both fiber-optic sensing and in-fiber polarization mode dispersion control and compensation.

According to the regulations of the European Parliament on fertilizer products, by July 2024, all substances used for coating fertilizers should be biodegradable. A series of coated fertilizers was prepared, which differed in the amount of applied coating layer. The core of the composition was granular ammonium nitrate, which contains 27% nitrogen. The effects of the amount of oil layers were examined. The article shows the results of IR testing and Iodine Value of the materials used. The coated fertilizer was evaluated for the release of nutrients under water conditions according to the standard ISO 21263, and the water samples were taken after every day for a 7-day period. The nitrogen content was analysed by elemental analysis. Microscopic pictures of the fertilizer composition were taken before release. The obtained product had potential controlled-release properties and was environmentally friendly. The tested material shows high potential as a component of a two-layer coated fertilizer. This type of fertilizer could be particularly useful in agricultural and horticultural applications.

We report on an experimental analysis of stimulated Brillouin scattering (SBS) in a $20\text{-}\mathrm{m}$-long highly birefringent microstructure fiber for sensing applications. In particular, an experimental setup based on Brillouin optical frequency-domain analysis, operating at a wavelength of $1550\mathrm{nm}$, has been employed in order to analyze the distribution of Brillouin frequency shift along the fiber, as well as to study the dependence of Brillouin frequency shift on optical polarization, temperature, and strain. Our results indicate that, for any fixed polarization, the fiber has a dual-peaked Brillouin spectrum. A study about the origin of these two peaks is presented.

We present the design of a low bending loss hole-assisted fiber for a 180°-bend fiber socket application, including a tolerance analysis for manufacturability. To this aim, we make use of statistical design methodology, combined with a fully vectorial mode solver. Two resulting designs are presented and their performance in terms of bending loss, coupling loss to Corning SMF-28 standard telecom fiber, and cut-off wavelength is calculated.