Institute of Electron Technology
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Spectroscopic Ellipsometry Analysis of Rapid Thermal Annealing Effecton MBE Grown GaAs1−x −Nx, Journal of Telecommunications and Information Technology, 2009, nr 1
Get PDFWe report on the effect of rapid thermal annealing (RTA) on GaAs1−x−Nx layers, grown by molecular beam epitaxy (MBE), using room temperature spectroscopic ellipsometry (SE). A comparative study was carried out on a set of GaAs1−x−Nx as-grown and the RTA samples with small nitrogen content (x = 0.1%, 0.5% and 1.5%). Thanks to the standard critical point model parameterization of the GaAs1−x−Nx extracted dielectric functions, we have determined the RTA effect, and its nitrogen dependence. We have found that RTA affects more samples with high nitrogen content. In addition, RTA is found to decrease the E1 energy nitrogen blueshift and increase the broadening parameters of E1, E1+Δ1, E′0 and E2 critical points
Control Mechanism for All-Optical Components, Journal of Telecommunications and Information Technology, 2009, nr 1
Get PDFIn this article, we give a brief overview of security and management issues that arise in all-optical networks (AONs). Then we present an outline of the multiple attack localization and identification (MALI) algorithm that can participate in some of the tasks for fault management in AONs. Consequently, we discuss a hardware-based control unit that can be embedded in AON nodes to accelerate the performance of the MALI algorithm. We conclude the article with a discussion concerning the applicability and implementation of this device in AON management systems
Si-Based Electrodes for Potentiometric Measurements of Aqueous Solutions, Journal of Telecommunications and Information Technology, 2009, nr 4
Get PDFThree sensors for chemical and physical examination of aqueous solutions were presented in the paper. An Au potentiometric electrode, an AgCl chlorine ion sensor and a p-n junction thermometer were developed. Their layout and internal structure were explained in the light of the manufacturing process. The device characteristics were measured in conditions corresponding to normal operation of the devices. Basic electrical parameters of the developed structures, as well as their sensitivity to environmental parameter variation were estimated
Rozwój szerokopasmowego internetu w Polsce – trendy i granice wzrostu. Telekomunikacja i Techniki Informacyjne, 2009, nr 1-2
Get PDFZaprezentowano modele i granice rozwoju internetu oraz odpowiedziano na pytanie, kiedy zanikną w Polsce różnice w dostępie do szerokopasmowego internetu. Zidentyfikowano naturalne granice rozwoju i wykazano, że kontynuacja dotychczasowego modelu rozwoju nie prowadzi do zmniejszenia istniejących dysproporcji. Wnioski te stanowią materiał do refleksji nad problemami budowy społeczeństwa informacyjnego w Polsce
Fault Tolerant Dense Wavelength Division Multiplexing Optical Transport Networks, Journal of Telecommunications and Information Technology, 2009, nr 1
Get PDFDesign of fault tolerant dense wavelength division multiplexing (DWDM) backbones is a major issue for service provision in the presence of failures. The problem is an NP-hard problem. This paper presents a genetic algorithm based approach for designing fault tolerant DWDM optical networks in the presence of a single link failure. The working and spare lightpaths are encoded into variable length chromosomes. Then the best lightpaths are found by use of a fitness function and these are assigned the minimum number of wavelengths according to the problem constraints using first-fit (FF) algorithm. The proposed approach has been evaluated for dedicated path protection architecture. The results, obtained from the ARPA2 test bench network, show that the method is well suited to tackling this complex and multi-constraint problem
Analytical Modelingof the WCDMA Interfacewith Packet Scheduling, Journal of Telecommunications and Information Technology, 2009 nr 3
Get PDFThe article presents the application of a new analytical model of the full-availability group carrying a mixture of different multi-rate traffic classes with compression property for modeling the WCDMA radio interface with packet scheduling. The proposed model can be directly used for modeling of theWCDMA interface in the UMTS network servicing different traffic classes. The described model can be applied for a validation of the efficiency of the WCDMA interface measured by the blocking probability and the average carried traffic for particular traffic classes
PHY Abstraction Methodsfor OFDM and NOFDM Systems, Journal of Telecommunications and Information Technology, 2009 nr 3
Get PDFIn the paper various PHY abstraction methods for both orthogonal and non-orthogonal systems are presented, which allow to predict the coded block error rate (BLER) across the subcarriers transmitting this FEC-coded block for any given channel realization. First the efficiency of the selected methods is investigated and proved by the means of computer simulations carried out in orthogonal muticarrier scenario. Presented results are followed by the generalization and theoretical extension of these methods for non-orthogonal systems
A Microscopic Approach for THz Intersubband Challenges, Journal of Telecommunications and Information Technology, 2009, nr 4
Get PDFThe main candidate to be a practical and low cost high power THz source is the intersubband-based quantum cascade laser, which can have a tremendous impact in many practical applications, including last mile and indoor telecommunication systems. In this review we discuss current challenges for THz intersubband device development from a microscopic point of view. Next summarize the search for new mechanisms and structure designs that can lead to intersubband gain without population inversion. This is a very important topic of current research, since is both an extremely elegant phenomenon from the basic physics of view and crucial for effective lasing in the THz range. The reason is that scattering phenomena can lead to level broadenings of the same order of magnitude of the lasing transitions, making population inversion by carrier injection in upper lasing subbands extremely difficult. Previous work in the literature is compared and contrasted with a new scheme that may lead to high temperature lasing by engineering the nonequilibrium population inversion with a combination of band structure and many body effects mediated by a k-space filter