Studium vlivu zakončení optických vláken na distribuci světla v prostoru pro vláknové segmentové vysílače

Abstract

This thesis deals with possibilities of optical fibres utilization as transmitters for mobile indoor optical fibreless networks through the Visible Light Communications (VLC) technology. The VLC currently includes together two main functions, illumination and communication. This thesis is systematically divided in several chapters, individual chapters introduce approach and design of optical segment transmitter. The thesis is divided in the theoretical part, which at the beginning deals with the wireless radio systems State of Art, then with development in communications and its transition to optical fibreless communication systems. The historic milestones and current state of art are described for both communication technologies. In the following chapters, the attention is directly led to optical fibreless systems particularly with regard to optical fibres utilizing for transmitters construction. In order to manage the task of this complicated transmitter design, the software LightTools was used. In LightTools software were studied and simulated conditions how to find an usable arrangement of fibres in geometric pattern compound of optical fibres, choice of optical fibres types, number of optical fibres, a misalignment of optical fibres, shapes of optical fibres ends and finally choice of measurement in space. All these mentioned parameters had to, in the final consequence, fulfil the criterion of effective coverage of a part of room with uniform optical intensity distribution in space when the optical power fluctuation does not exceed 3 dB. During selection of used optical fibre was found that better parameters, from the point of view of uniform optical intensity distribution in space, were obtained with multi-mode optical fibres. The main thesis part is devoted to simulations. The model design of optical segment transmitter on the basis of optical fibres was created in the LightTools software, which was followed by evaluation of its optical properties. Designed models of optical transmitters were then ground for fabrication of real optical segment transmitters prototypes measured in the dark room. The pivotal assets of this thesis are then simulations and different prototypes fabrication of optical transmitters for uniform elimination of defined area. Thesis in its conclusion summarise main benefits and feasible future development directions of optical segment transmitters on the basis of optical fibres.