Elastic Wave Eigenmode Solver for Acoustic Waveguides

A numerical solver for the elastic wave eigenmodes in acoustic waveguides of inhomogeneous cross-section is presented. Operating under the assumptions of linear, isotropic materials, it utilizes a finite-difference method on a staggered grid to solve for the acoustic eigenmodes of the vector-field elastic wave equation. Free, fixed, symmetry, and anti-symmetry boundary conditions are implemented, enabling efficient simulation of acoustic structures with geometrical symmetries and terminations. Perfectly matched layers are also implemented, allowing for the simulation of radiative (leaky) modes. The method is analogous to eigenmode solvers ubiquitously employed in electromagnetics to find waveguide modes, and enables design of acoustic waveguides as well as seamless integration with electromagnetic solvers for optomechanical device design. The accuracy of the solver is demonstrated by calculating eigenfrequencies and mode shapes for common acoustic modes in several simple geometries and comparing the results to analytical solutions where available or to numerical solvers based on more computationally expensive methods

Integrated optical isolators using electrically driven acoustic waves

We propose and investigate the performance of integrated photonic isolators based on non-reciprocal mode conversion facilitated by unidirectional, traveling acoustic waves. A triply-guided waveguide system on-chip, comprising two optical modes and an electrically-driven acoustic mode, facilitates the non-reciprocal mode conversion and is combined with modal filters to create the isolator. The co-guided and co-traveling arrangement enables isolation with no additional optical loss, without magnetic-optic materials, and low power consumption. The approach is theoretically evaluated and simulations predict over 20 dB of isolation and 2.6 dB of insertion loss with 370 GHz optical bandwidth and a 1 cm device length. The isolator utilizes only 1 mW of electrical drive power, an improvement of 1-3 orders of magnitude over the state-of-the-art. The electronic driving and lack of magneto-optic materials suggest the potential for straightforward integration with the drive circuitry, possibly in monolithic CMOS technology, enabling a fully contained `black box' optical isolator with two optical ports and DC electrical power.Comment: 14 pages, 5 figures, 1 table. Relies on an acoustic-optical multiplexer introduced in arXiv:2007.11520, which has been separated out in this updated version of the paper for clarity. Additionally, this updated version included additional discussion of design considerations of the isolato

E-Agriculture: Montenegro Case

The use of information technology in the field of agriculture is one of the biggest challenges in the field of agriculture in economic transition in Montenegro. Montenegrin society has made significant progress in the development of agriculture, but there are difficulties in the implementation of modern technologies in all phases of agricultural production. The importance of ICT application in agriculture is very significant from the standpoint of reductions in manufacturing costs, yield increase, protection of the environment, etc. This paper will deal with the problems and proposed solutions (examples) for the application of ICT in the production process, in the process of planning and reporting within the agricultural sector. The research focuses on a comparison of the current situation in the Montenegrin agricultural sector with the situation at the EU level as well as several global initiatives. ICT application in agriculture is also important from the point of view of producers (small and large), and from the standpoint of the state in terms of monitoring the implementation of planned activities. Therefore, it is crucial for Montenegro to keep developing in this field. This paper could also serve as a guideline for the Government in implementation of development policies in the e-Agriculture field. This work is licensed under a&nbsp;Creative Commons Attribution-NonCommercial 4.0 International License.</p