Although experimental advances in the implementation and characterization of fiber speckle sensor have been reported, a suitable model to interpret the speckle-pattern variation under perturbation is desirable but very challenging to be developed due to the various factors influencing the speckle pattern. In this work, a new methodology based on the finite element method (FEM) for modeling and optimizing fiber specklegram sensors (FSSs) is proposed. The numerical method allows computational visualization and quantification, in near field, of changes of a step multi-mode fiber (SMMF) specklegram, due to the application of a uniformly distributed force line (UDFL). In turn, the local modifications of the fiber speckle produce changes in the optical power captured by a step single-mode fiber (SSMF) located just at the output end of the SMMF, causing a filtering effect that explains the operation of the FSSs. For each external force, the stress distribution and the propagations modes supported by the SMMF are calculated numerically by means of FEM. Then, those modes are vectorially superposed to reconstruct each perturbed fiber specklegram. Finally, the performance of the sensing mechanism is evaluated for different radius of the filtering SSMF and force-gauges, what evidences design criteria for these kinds of measuring systems. Results are in agreement with those theoretical and experimental ones previously reported.

The published data correspond to images of simulated specklegrams, which result from the calculation of the modal interference that occurs in a multimode optical fiber. These have a characteristic pattern due to the constructive or destructive interference between the light modes depending on their phase differences. The specklegram contains valuable information since the propagation of the modes varies according to the influence of some external disturbances, and therefore, the speckle pattern changes. This dataset contains specklegrams that vary according to the temperature. These data have been obtained by simulation using the finite element method (FEM) through the COMSOL multiphysics platform. In the simulation, the vector wave equation is solved, and the refractive index of the fiber is recalculated due to the temperature change. We simulated a 1490 nm wavelength laser, an optical fiber with a core diameter of 50 µm and cladding diameter of 125 µm. The dataset contains specklegrams covering the range of temperatures from 0°C to 120°C in 0.2°C steps.

A numerical approach based on the scalar finite element method is applied to analyse the modal properties of photonic crystal fibers having a solid core and a cladding region with either circular or non-circular microstructured holes. A correction which accounts for the polarization effects due to the large refractive index difference between silica materials and air holes is included in the analysis. Numerical results show that the proposed technique is an efficient and accurate alternative to vector ones.

In this paper, a method for performance parameters estimation of Pockels high-voltage sensors by means of numerical optimization is presented. The proposed method integrates a theoretical model for simulation of Pockels sensors, and the optimization algorithm Pattern Search to estimate the model parameters in order to minimize the difference between the experimental and theoretical peak-peak output voltage. Two Pockels cells were built and tested for validation of the method, where model parameters estimated by means of numerical optimization were substituted in the theoretical model and compared with the experimental data for the peak-peak output voltage and output voltage in function of time, presenting a high degree of agreement between them, showing that the optimization resulted in a good solution.

At a global level, hydrokinetic power has been considered as a renewable energy source, and it has become an attractive alternative for the rural electrification of non-interconnected areas with the presence of water resources. Aspects such as the low rural electrification rate, the increase in energy demand, the decrease in fossil reserves and the climate change, are some of the factors that have driven the use of this technology for the electricity production. The aim of this work is to give a review of the hydrokinetic energy potential of water resources, the requirements and impacts of the implementation of hydrokinetic technology in different countries, and the current development in the Colombian case. At present, it can be observed that the implementation of this technology in different regions of the world, especially in Colombia, has several challenges and barriers, including gaps in knowledge, information and data, such as well as limitations of water resources and infrastructure, finally, impacting on a low adoption of this technology. On the other hand, publications on studies of implementation and potential of hydrokinetic technology have been increasing over time, indicating that this topic has been gaining interest despite the challenges.