Does Russia Have the Possibilities to Diversify Its Export Potential to Manage the Power Engineering (For Example, Nuclear Power Development)?

The article analyzes the current state of power engineering, nuclear power, and their role in ensuring energy independence of Russia. According to the author, the creation of large high-tech integrated companies with active innovation state practice can bring the Russian economy to a higher level of development. To maintain Russia’s leading role in the construction of nuclear power plants abroad, according to the author, it is necessary to optimize cost and terms of construction of projects, improve designs, increase scopes and quality of specialists’ training, and fight corruption

Theory of Polarization Attraction in Parametric Amplifiers Based on Telecommunication Fibers

We develop from first principles the coupled wave equations that describe polarization-sensitive parametric amplification based on four-wave mixing in standard (randomly birefringent) optical fibers. We show that in the small-signal case these equations can be solved analytically, and permit us to predict the gain experienced by the signal beam as well as its state of polarization (SOP) at the fiber output. We find that, independently of its initial value, the output SOP of a signal within the parametric gain bandwidth is solely determined by the pump SOP. We call this effect of pulling the polarization of the signal towards a reference SOP as polarization attraction, and such parametric amplifier as the FWM-polarizer. Our theory is valid beyond the zero polarization mode dispersion (PMD) limit, and it takes into account moderate deviations of the PMD from zero. In particular, our theory is capable of analytically predicting the rate of degradation of the efficiency of the parametric amplifier which is caused by the detrimental PMD effect

Harmonic and supercontinuum generation in quadratic and cubic nonlinear optical media

We present numerical simulations by means of the generalized nonlinear envelope equation f harmonic and supercontinuum generation induced by femtosecond pump pulses in optical media with both quadratic and third-order nonlinearities. Application examples to higher harmonic generation in periodically poled lithium niobate and optical parametric generation of a mid-infrared continuum in gallium arsenide are discussed

Quasi-parabolic pulses in a coherent nonlinear optical amplifier

We show that, in a coherent two-level optical amplifier with Kerr nonlinearity and linear loss, any weak seed pulse evolves into a fixed powerful linearly chirped pulse with quasi-parabolic shape. This process is associated with a transition from the incoherent into the coherent amplification regime, thus enabling in practice the generation of pulses with a spectrum wider than the linear gain bandwidth

Analytic theory of fiber-optic Raman polarizers

The Raman polarizer is a Raman amplifier which not only amplifies but also re-polarizes light. We propose a relatively simple and analytically tractable model - the ideal Raman polarizer, for describing the operation of this device. The model efficiently determines key device parameters such as the degree of polarization, the alignment parameter, the gain and the RIN variance

Theoretical study of optical fiber Raman polarizers with counterpropagating beams

The theory of two counter-propagating polarized beams interacting in a randomly birefringent fiber via the Kerr and Raman effects is developed and applied to the quantitative description of Raman polarizers in the undepleted regime. Here Raman polarizers, first reported by Martinelli et. al. [Opt. Express. 17, 947 (2009)], are understood as Raman amplifiers operating in the regime in which an initially weak unpolarized beam is converted into an amplified fully polarized beam towards the fiber output. Three parameters are selected for the characterization of a Raman polarizer: the degree of polarization of the outcoming beam, its state of polarization, and its gain. All of these parameters represent quantities that are averaged over all random polarization states of the initially unpolarized signal beam. The presented theory is computer friendly and applicable to virtually all practically relevant situations, including the case of co-propagating beams, and in particular to the undepleted as well as the depleted regimes of the Raman polarizer.Comment: 16 pages, 5 figures, to be submitted to the Journal of Lightwave Technolog

Nonlinear repolarization in optical fibers: polarization attraction with copropagating beams

3openopenKozlov, V.; Turitsyn, K.; Wabnitz, S.Kozlov, Victor; Turitsyn, K.; Wabnitz, Stefa