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The increasing evolution and development of telecommunications as well as the need for wider bandwidths to comply with the users’ needs, has led to the development of the so-called free space optical communications. The advantages of optical communications in comparison to radio frequency communications draw interest for certain military applications. This paper describes the simulation, development and implementation of an optical communication system which integrates the various functional blocks of the optical emitter and the optical receiver and presents some theoretical considerations about the specific characteristics of the propagation of the optical signals in free space. The implementation of this system in military vehicles to allow wider bandwidth in military communications, as well as to function as an alternative system to the used systems, is one of the objectives of this dissertation. For this purpose, two circuits (emitter and receiver) were projected and designed including the design of printed circuit boards (PCB) and performed some simulations of the optical part of the complete system and the electronic simulation of some parts of the electronic circuits.

In this paper, the mechanism of energy transfer between two bent-bent waveguides is analyzed. Focus is done to the effect that some parameters like the refractive index of the substrate and the wavelength cause in the energy rate transfer between the waveguides. Results were validated by using the Finite Element Method (FEM).

Nanoscience and nanotechnology are emerging fields where some phenomena were recently discovered, allowing the design of some new devices. One of these phenomena is extraordinary optical transmission - EOT -, which was discovered in 1998 by Ebbesen. He reported that light can be amplified in certain conditions, due to a resonant behaviour, using metallic arrays. Even more, he associated this behaviour to surface plasmon polaritons and suggested that devices, as optical sensors, can be designed based on this phenomenon. To understand the surface plasmon polaritons theory, classical theories will be studied and compared with it. Also, the composite diffracted evanescent waves - CDEW -, model, which is not the most accurate model in comparison with the surface plasmon polaritons, will be presented, in order to cover an important topic on the theoretical foundations. After it, the application of nanoantennas as a sensor is going to be analysed. Finally, stationary simulations for a 16-slit gold array were performed using COMSOL Multiphysics and they are going to be presented in order to observe the occurrence of EOT.