This paper presents a full-wave electromagnetic analysis of soft-glass photonic crystal fibers developed for the generation of supercontinuum based on third-order nonlinearity. It is shown that a two-dimensional finite-difference time-domain method for guided problems provides results very similar to the measurement data of real fiber structures, enabling the reduction of costly hardware prototyping, thus, opening the way for the application of FDTD to the modeling of nonlinear optical processes.

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An algorithm accounting for dispersive and thirdorder nonlinear effects in a vector two-dimensional FDTD method is developed and validated in this paper. Kerr and Raman phenomena are implemented in FDTD using a new approach, which combines the accuracy of a rigorous FDTD update scheme and the speed of an approximate solution. As it is shown in this paper, the proposed method is applicable to the mode analysis of waveguide structures, like photonic crystal fibers, where the appropriate balance between dispersion and nonlinear phenomena is essential for supercontinuum generation. Several computational examples discussed in this paper successfully validate the proposed method.

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A Fabry–Pérot open resonator is a tool dedicated to broadband accurate microwave and mm-wave characterization of dielectric sheets. It has been applied in this paper to the measurement of the dielectric constant and loss tangent of various types of commonly used dielectric materials, such as semiconductors, electronic substrates, glasses, and plastics, in the 20–110 GHz range. The obtained results are in good agreement with the literature data, which are, however, often available only at discrete frequencies, thus making it difficult to recognize dispersive properties of the measured samples. It is shown in this paper that broadband measurement of high-resistivity and intrinsic silicon allows extracting their resistivity solely due to conduction losses. In the case of typical electronic substrates, it is shown that their dielectric constant is almost non-dispersive, whereas losses are, in general, linearly increasing with frequency. Glasses also exhibit almost non-dispersive dielectric constant, which is, however, larger than 3.8, whereas their losses can vary by over two orders of magnitude depending on the properties, like the hydroxyl content. The lowest dielectric constant is easily achievable in common plastics, spanning from ca. 2.03 for Teflon up to ca. 3.0 for PETG.

Asphalt pavement construction technology is an industry branch that undergoes constant development. Analyzing the directions of the development, one can divide it into two mainstreams: the development of roadworks equipment and the development of roadworks technology. Microwave heating technique has been mentioned in the road industry from the early ‘70s, but research records from practical full-scale use are very rare. This article presents the evaluation of the possible use of microwave heating technique during a particular aspect of the construction process, namely, the formation of longitudinal joints and the potential repair process of the cracked asphalt pavement. Research results showed that joints constructed using microwave-assisted heating performed the same or even better with regards to tensile characteristics comparing to other techniques. Also, the highest level of compaction was reached among the other tested techniques applied to the wearing course level. The second part of the research experiment showed the large potential of the microwave crack healing technique. The asphalt pavement was healed on its full depth of 10 cm with the single healing operation applied. Although some limitations may occur in the practical use of microwave heating, the test results suggest that it is a very promising technique and should be further developed (for, e.g., shielding concerns, electricity supply). The microwave heating technique is powered with electricity, which is important when there is a constant need for further reductions of CO2 emissions. It can be reached in parallel with clean energy or clean electricity sources.

The special features of photonic crystal fibres (PCFs) are achieved by their air hole structures. PCF structure is determined and formed by its origin preform design and drawing process. Therefore, structure formation dynamics in drawing PCF is important for the fabrication of PCF achieving desirable structure and thus the intended feature. This paper will investigate structure formation dynamics of PCF drawing in relation to key parameters and conditions, such as hole dimension, temperature, pressure, etc.