Extreme value statistics in Raman fiber lasers

We present the numerical study of the statistical properties of the partially coherent quasi-CW high-Q cavity Raman fiber laser. The statistical properties are different for the radiation generated at the spectrum center or spectral wings. It is found that rare extreme events are generated at the far spectral wings at one pass only. The mechanism of the extreme events generation is a turbulent-like four-wave mixing of numerous longitudinal generation modes. The similar mechanism of extreme waves appearance during the laser generation could be important in other types of fiber lasers. © 2012 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

From rogue waves to random walks:nonlinear instabilities in supercontinuum generation

The noise properties of supercontinuum generation continue to be a subject of wide interest within both pure and applied physics. Aside from immediate applications in supercontinuum source development, detailed studies of supercontinuum noise mechanisms have attracted interdisciplinary attention because of links with extreme instabilities in other physical systems, especially the infamous and destructive oceanic rogue waves. But the instabilities inherent in supercontinuum generation can also be interpreted in terms of natural links with the general field of random processes, and this raises new possibilities for applications in areas such as random number generation. In this contribution we will describe recent work where we interpret supercontinuum intensity and phase fluctuations in this way.

Optical rogue waves in telecommunication data streams

Large broadening of short optical pulses due to fiber dispersion leads to a strong overlap in information data streams resulting in statistical deviations of the local power from its average. We present a theoretical analysis of rare events of high-intensity fluctuations-optical freak waves-that occur in fiber communication links using bit-overlapping transmission. Although the nature of the large fluctuations examined here is completely linear, as compared to commonly studied freak waves generated by nonlinear effects, the considered deviations inherit from rogue waves the key features of practical interest-random appearance of localized high-intensity pulses. We use the term "rogue wave" in an unusual context mostly to attract attention to both the possibility of purely linear statistical generation of huge amplitude waves and to the fact that in optics the occurrence of such pulses might be observable even with the standard Gaussian or even rarer-than-Gaussian statistics, without imposing the condition of an increased probability of extreme value events. © 2011 American Physical Society.

Solitons: permanent waves

Communications engineers are learning to create an electromagnet wave at will, to transmit information. This wave, the optical soliton, is the subject of astounding recent developments in nonlinear optics and lasers. The author describes the principles behind the use of solitons in optical communications and shows that in the context of such communications the most important property of solitons is that they are extremely stable. Not only do they not disperse, but an encounter with a perturbation (e.g. a joint in optical fibre) will usually leave the soliton unaltered.

Fundamental characteristics of space-charge waves in photorefractive sillenite crystals

We investigate experimentally the fundamental characteristics of space-charge waves excited in a photorefractive crystal of Bi12SiO20. Features such as their transient rise and decay as well as their steady-state frequency response are investigated. Based on this, we find the dependence of the space-charge waves' quality factor on spatial frequency and electric-field biasing. The experimental findings are compared with the linear space-charge wave theory developed previously by Sturman et al. [J. Opt. Sec. Am. B 10, 1919 (1993)].

The extreme right in France:from Pétain to Le Pen

The Front National has for some years been France's third political party and the most notable far-right force in Europe; its leader, Jean-Marie Le Pen, contested the 2002 presidential election run-off with 5.5 million votes. What do Le Pen and the FN represent? What are their historical roots, their values and their policies? Who votes for them and why? And what has been their impact on the political agenda in France? Adopting an essentially chronological approach, the book traces the political lineage of Le Pen and the FN through key figures, movements and events on the French extreme right from the Vichy regime to the present, providing a detailed historical perspective for understanding the FN today. Part I provides a historical study of the extreme right in France since 1940, examining • the Vichy regime, collaboration and ‘collaborationism’, • the aftermath of Liberation and the post-war extreme right, • the Poujadist movement and the politics of populism, • the Algerian War as a catalyst for change, • the ‘Nouvelle Droite’ and the search for doctrinal renewal, • old and new forms of extreme-right ideology and activism. Part II undertakes a comprehensive study of the FN, analysing • the party’s early development and electoral rise, • its evolving programme and strategy, • the factors underlying its popular appeal, • the geography and composition of its electorate, • its exercise of local power and regional influence, • and its defining impact on the national political agenda. The FN, it is argued, represents both the latest manifestation of a long tradition of authoritarian nationalism and a complex new phenomenon within the changing social and political dynamics of contemporary France.

Business cycles, long waves, and company langevity in Birmingham area metal industries 1780-1980

This doctoral thesis originates from an observational incongruence between the perennial aims and aspirations of economic endeavour and actually recorded outcomes, which frequently seem contrary to those intended and of a recurrent, cyclical type. The research hypothesizes parallel movement between unstable business environments through time, as expressed by periodically fluctuating levels of economic activity, and the precipitation rates of industrial production companies. A major problem arose from the need to provide theoretical and empirical cohesion from the conflicting, partial and fragmented interpretations of several hundred historians and economists, without which the research question would remain unanswerable. An attempt to discover a master cycle, or superimposition theorem, failed, but was replaced by minute analysis of both the concept of cycles and their underlying data-bases. A novel technique of congregational analysis emerged, resulting in an integrated matrix of numerical history. Two centuries of industrial revolution history in England and Wales was then explored and recomposed for the first time in a single account of change, thereby providing a factual basis for the matrix. The accompanying history of the Birmingham area provided the context of research into the failure rates and longevities of firms in the city's staple metal industries. Sample specific results are obtained for company longevities in the Birmingham area. Some novel presentational forms are deployed for results of a postal questionnaire to surviving firms. Practical demonstration of the new index of national economic activity (INEA) in relation to company insolvencies leads to conclusions and suggestions for further applications of research into the tempo of change, substantial Appendices support the thesis and provide a compendium of information covering immediately contiguous domains.

Fundamental characteristics of space-charge waves in photorefractive sillenite crystals

We investigate experimentally the fundamental characteristics of space-charge waves excited in a photorefractive crystal of Bi12SiO20. Features such as their transient rise and decay as well as their steady-state frequency response are investigated. Based on this, we find the dependence of the space-charge waves' quality factor on spatial frequency and electric-field biasing. The experimental findings are compared with the linear space-charge wave theory developed previously by Sturman et al. [J. Opt. Sec. Am. B 10, 1919 (1993)].

La presse d'extreme droite face au revisionnisme en France 1978-1990

Between 1978 and 1990 five newspapers close to Jean-Marie Le Pen's Front National had the choice of defining their stand on so-called révisionnisme which in its extreme form denied the existence of the Shoah, considering it to be the fabrication of a Jewish conspiracy. Within révisionnisme, a négationniste discourse affirmed that the gas chambers never existed, while a relativiste discourse denied that the Shoah was an act of genocide. However, most of the extreme-right newspapers did not adopt the cause of révisionnisme, even if they sometimes evinced an indulgence towards it. Only the weekly Rivarol and the militant François Brigneau who worked for Minute, Présent and National Hebdo and wrote the most on the subject openly espoused révisionnisme. The reasons for their stance included neo-fascist views, belief in a Jewish conspiracy. Their stance was in keeping with ideas commonly expressed in French neo-fascist circles that made for a révisionnisme of exculpation. On the other hand, the French Catholic intégriste milieu close to the Front National, which is represented by the newspapers Présent and Aspects de la France, was not generally révisionniste, notwithstanding the occasionnal expressions of relativisme by persons in the schismatic lefebvriste movement or close to Présent. This rejection of révisionnisme by Catholics on the extreme right was conditioned by various factors: the nature of Maurras's nationalisme intégral and anti-Semitism transmitted by I' Action française; the Catholic Church's modified position on the Jews; and the (offensive) atheism of the upholders of révisionnisme. This same révisionnisme extended beyond latter-day Nazi sympathisers. In its French version, it served to unite elements of the extreme right and the extreme left, as witness the role played by La Vieille Taupe, the extreme left group which was (and is) the leading publisher in France of tracts favouring révisionnisme.

Localized waves in optical systems with periodic dispersion and nonlinearity management

We overview our recent developments in the theory of dispersion-managed (DM) solitons within the context of optical applications. First, we present a class of localized solutions with a period multiple to that of the standard DM soliton in the nonlinear Schrödinger equation with periodic variations of the dispersion. In the framework of a reduced ordinary differential equation-based model, we discuss the key features of these structures, such as a smaller energy compared to traditional DM solitons with the same temporal width. Next, we present new results on dissipative DM solitons, which occur in the context of mode-locked lasers. By means of numerical simulations and a reduced variational model of the complex Ginzburg-Landau equation, we analyze the influence of the different dissipative processes that take place in a laser.