Ján Turán

Fiber optic refractometer for liquid index of refraction measurements

Refractometers frequently are used for medical, pharmaceutical, industrial fluid, petrochemical, plastic, food, and beverage industry applications. For example, they are used for measuring the concentrations of aqueous solutions: as the concentration or density of a solute increase, the refractive index increases proportionately. The paper describe development work of a flexible fiber optic refractometer and its evaluation.

Long term availability analysis of experimental free space optics system

This paper deals with Free Space Optics (FSO) systems. Availability and reliability of FSO is taken under the scope. FSO links transmit data within the infrared wavelength region. Lasers are used to create medium to carry informational stream. FSO systems need Line of Sight (LOS) technology in order to maintain connection between two points. Weather conditions have quite significant impact on FSO operation in terms of availability and reliability because of free space transmission. It is necessary to evaluate the air quality at the actual geographical location where FSO link is located. It is important to determine the impact of a light scattering, absorption, turbulence and receiving power at the particular FSO link. Visibility has one of the most critical impacts on the quality of an optical transmission channel. Moreover, it is very helpful to monitor and store the information about rain, snow and fog values. This paper introduces a device which measures all mentioned weather indicators such as a fog density, a relative humidity and the temperature. FSO availability and reliability estimation is made from measured data. These results evaluate weather conditions for Kosice, Slovakia in term of FSO operation.

LSB steganography with usage of Mojette Transform for secret image scrambling

Many steganographic algorithms have been proposed until these days. They all try to hide information by relying on some of well-known techniques. However, each of these techniques has its advantages and also its drawbacks. In this paper, we have investigated a possibility of using tool known as Mojette Transform for modifying and scrambling a binary image containing secret information. The image after these processes should resemble noisy picture. Modified image is then embedded into the least significant bit plane of cover image. The used techniques should result in better values of parameters as MSE, or PSNR in comparison with performance of the classical Least Significant Bit steganography.

Stimulated Brillouin scattering in DWDM all optical communication systems

This work on the introduction deals with phenomena affecting the signal transmission in optical fibers. The core of the work is focused on nonlinear phenomenon SBS, one of the dominant nonlinear effects in optical communication systems. The main idea is impact of SBS at fully WDM optical communication systems. Therefore, it will also debated WDM technology, namely DWDM. The work will also be solution suppressing of the effects SBS on communication systems. And as well as the impact of optical fiber on the SBS threshold. Design and simulation will be executed in the programming environment Optsim.

Inventory System of Vertical Traffic Signs

Control systems in general are very important in these days. There are used in many industrial fields such as automotive, medicine and manufacture. This paper contains a draft of VTSIS (Vertical Traffic Signs Inventory System). VTSIS has wide application in the control of traffic signs, which number is increasing annually. Cambridge optical correlator is used in designed inventory system as comparator. The use of optical processing technology will increase the speed of processing amounts of data.

An image encryption scheme employing key related skipping

Abstract This paper describes an image encryption algorithm which utilizes chaotic logistic map. Values generated by this map are used in two steps of algorithm which shuffles image pixels and then changes their intensities. Design of the encryption scheme considers possibility of various attacks, such as statistical, differential or phase space reconstruction attacks. Robustness against last mentioned type of attacks is introduced by selective skipping of values generated by the map. This skipping depends on key entered by user. The paper also verifies properties of proposed algorithm by common measures and by set of statistical tests that examine randomness of computed encrypted images. Results are compared with other approaches and they are also briefly discussed.

An Image Encryption Algorithm with Total Diffusion

Abstract This paper proposes an image encryption algorithm which uses four scans of an image during the diffusion stage in order to achieve total diffusion between intensities of image pixels. The condition of total diffusion is fulfilled by a suitable combination of techniques of ciphertext chaining and plaintext related diffusion. The proposed encryption algorithm uses two stages which utilize chaotic logistic map for generation of pseudo-random sequences. The paper also briefly analyzes approaches described by other researchers and evaluates experimental results of the proposed solution by means of commonly used measures. Properties of our proposal regarding modifications of plain images prior to encryption or modifications of encrypted images prior to decryption are illustrated by two additional experiments. The obtained numeric results are compared with those achieved by other proposals and briefly discussed.

Simulation of Downlink of 10G-PON FTTH in the city of Košice

Abstract Optical fiber has the great advantages of capacity and reliability. That is why network providers started to deploy FTTx (Fiber-To-The-x) optical access using various PON (Passive Optical Network) architectures. The leading technology right now is Gigabit PON (GPON). However, with increasing amount of multimedia we need to further develop existing technologies to go on with these high demands. Fiber-To-The-Home (FTTH) using 10G-PON technology for broadband access application is effective solution for high speed networks with high capacity. In this paper, we look at the passive optical network in the city of Košice and based on the real network we created simulation model of downlink of 10G-PON based FTTH with triple-play service.

Design of Pyramidal Horn Antenna for 2.45GHz in FEKO for Application in Experimental FSO/RF Hybrid System

Abstract Communication technologies are growing for day to day because demand on data sharing is unstoppable. Users require availability of approach to network at all time. Implementation of smart technologies allows communication of all type of devices. Capacity of data flow have to grow. Video formats HD or 4K require transmit on high data speed. Based on the demands many types of different communication systems which are suitable for these speeds were designed. One of these systems is FSO (Free Space Optics). FSO system is based on transmission of optical beams which carry the information. This system allow high data speed comparable with standard optical fiber in range to 10km. One of drawbacks of this system is LOS (Light of Sight) between communication points. The other drawback is sensitivity to weather changes. Optical beams interfere with water particles and cause attenuation on transmission path. The solution is in implementation using hybrid FSO/RF system which combines optical communication system with RF (Radio Frequency) backup link. We realized FSO communication link on Technical University of Košice. Our research is focused on design of appropriate type of antenna for our RF backup link. Our results in this area were published.

The four-channel WDM system using Semiconductor Optical Amplifier

This article focuses on the creation of a four-channel WDM (Wavelength Division Multiplexing) system using SOA (Semiconductor Optical Amplifier) at the speed of 10 Gbps and the spacing of 1nm. In creating an optical network it is necessary to utilise software tools simulating a real optical network under the given conditions. Evaluation of the optical line quality for the respective channel is performed on the basis of BER (Bit Error Rate). The result of the article is a WDM system in a simulated environment evaluating BER at particular stream in SOA. The wavelengths compared were of 1549 nm and 1550 nm at pump current in the SOA: 0.05 A, 0.1 A and 0.2 A.