Journal of Telecommunications and Information Technology
We propose a review of word science achievements in the extremely extended for the recent few years field of photonic band gap structures The review concerns both theoretical and experimental investigations on PBG structures toward fabrication of the most optimal ones for different applications. The attention is given to the obtained results as well as to the used and developed methods.
A state-of-the art of photonic telecommunication technology is reviewed and possible directions of future developments are outlined. In particular, the impact of nonlinear optical phenomena inherent to silica glass on the transmission performance of wavelength-division multiplexed optical signal through fibres is discussed. Also potential applications of nonlinear photonic devices for the purposes...
A possibility of light pulse transformation by transient reflecting medium is investigated theoretically. After solving 1D problem of such a reflection one estimates such a transformation in a plane optical waveguide with time-dependent conductivity of one of the reflected media. Three types of the conductivity time-dependences are considered: harmonic, Bessel-like and splash-like ones. Obtained results...
A time-domain model of a semiconductor layer with time-dependent inhomogeneous permittivity or conductivity is investigated by solving direct and inverse problems using a novel method, revealing a possibility of wavelength shifting and other desirable optical field transformation, as well as a remote diagnostics of fast time-varying inhomogeneous structures.
Optical range electromagnetic field interaction with inhomogeneous finite dielectric media is investigated. New method for analysis of this interaction in 1D case based on integral equations for fields in transient media is proposed. Some special cases of quasi-periodical structures with doubled quasi-periodicity are investigated numerically. A possibility to obtain good filtering properties in such...
Arbitrary shape optical pulses in nonlinear guides are discussed. The Nonlinear Schrödinger Equation for complex initial conditions is solved numerically using Split-Step Fourier Method and some selected results for solitons are presented. The computations confirm physical expectations of an influence of the chirp magnitude on pulse propagation in nonlinear guide.
Motivated by the analogy between a phase-conjugating mirror (PCM) and a superconductor, we search for optical counterparts of the well-known DC and AC Josephson effects. We show that in a system consisting of two PCM's separated by vacuum an 'optical supercurrent' arises as a function of an applied phase difference between the PCM's, which is the optical analogue of the DC supercurrent flowing in...
In the paper results of analysis of nonlinear phenomena in optical fibres: Self-Phase Modulation, Cross-Phase Modulation, Four-Wave Mixing and Stimulated Raman Scattering and their influence on Dense-Wavelength Division Multiplexed system performance are reported. Different nonuniform optical channel allocation schemes based on ITU Recommendation G.692 100 GHz frequency grid are compared with uniform...
In this paper we present results of an investigation into the power penalty introduced by Stimulated Raman Scattering (SRS) in WDM systems with concentration on application of dispersion-shifted single-mode optical fibres (G.653) and unequal channel allocation schemes. System parameters based on ITU-T Recommendation G.692 and analytic formulas were used in calculations. It is shown that SRS does present...
The former Research Laboratory for Crystal Physics continues the growth and defect structure investigation of nonlinear optical single crystals in a new organization, as a part of the Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences. The aim of the activity is to prepare specific crystals for basic and applied research as well as for applications. We improve the...
CdS nanoparticles embedded in Nafion membranes were studied by a variety of optical spectroscopic methods. Quantum confinement was achieved (particle mean diameter of 40 A) and the growth was found to follow a linear temporal kinetic law. Discrete energy levels were observable, even at room temperature. They could be attributed to light hole and heavy hole IS and 2S transitions. The experimental results...
A number of manners to obtain first-order achromatic phase matching of both type I and type II are presented and the most advantageous ones are identified to generate high-spectral quality 100-fs pulses by either parametric generation or frequency up-conversion. In the case of frequency-doubling high-energy 5-fs Ti: sapphire pulses, a non-collinear phase-matching I geometry in a beta-barium borate...
The theory of electromagnetic wave eigenmodes propagating on open dielectric and metallic waveguides has been reviewed. The main steps of different theoretical approaches to the problem are outlined and discussed. The unsolved problems and also directions of future development are pointed out.
We examine nonlinear optical effects in the active medium of the thin-film quasiwaveguide amplifier-oscillator with injection of the external signal. The injection locking has been obtained in the case when both the frequency and the direction of propagation of the injected signal differ from those for a free-running thin-film laser which offers a possibility for the frequency and directional switching...
The optical frequency shift of an electromagnetic wave reflecting from a boundary of a medium is studies for two cases: for temporal variations of medium permittivity, and for a moving plasma boundary. It has been shown that a simultaneous occurence of both cases leads to an enhanced frequency shift.
In this paper, we review a number of recent developments concerning laser or laser-based sources generating pico- or subpicosecond pulses of light at wavelengths now ranging from the mid Infra-Red (50 ľm) to the XUV (11,9 nm). Those include the new generation of 'Chirp Pulse Amplification' laser systems, Free Electron Lasers operating in the IR or visible range, and a number of laser driven sources...
A possibility of side lobes level reducing in plane antenna array by creation of aperture comb edge in arrays with rectangular and circular aperture shape together with usage of different types of reducing to the array edges amplitude distributions is investigated by computer analysis. It is shown that usage of the comb structure in combination with the reducing amplitude distribution enables one...
Optical wave reflection from a layered half-space with regular and random inhomogeneities where the regular perturbations correspond to a linear waveguide near the half-space boundary. Random inhomogeneities are simulated in the frame of the white noise model. The problem is solved analytically in a framework of the embedding method which reduces a boundary problem to the problem with initial values...
The high frequency performances including microwave noise parameters for sub-quarter micron fully- (FD and partially-depleted (PD) silicon-on-insulator (SOI) n-MOSFETs are described and compared. Direct extraction techniques based on the physical meaning of each small-signal and noise model element are used to extract the microwave characteristics of various FD and PD SOI n-MOSFETs with different...
SiGe-base HBTs with Gaussian doping distribution are modeled including the effect of the drift field and variable Ge concentration in the base on the diffusion coefficient. Two different Ge distributions in the base are considered: a triangular one and a box one.