Novel applications of fibre tapers

In this talk we will discuss new applications for fibre tapers ranging from femtosecond pulse manipulation to optical clock generation in micro-coil resonators. Fundamental to these interactions is the enhanced nonlinearity arising from the smaller cores making compact optical devices possible

Efficient binary phase quantizer based on phase sensitive four wave mixing

We experimentally demonstrate an efficient binary phase quantizer operating at low pump powers. Phase-sensitive operation is obtained by polarization mixing the phase-locked signal/idler pair in a degenerate dual-pump vector parametric amplifier

Novel polarization-assisted phase sensitive optical signal processor requiring low nonlinear phase shifts

We demonstrate a new scheme to achieve binary step-like phase response and high phase-sensitive extinction ratio at low powers. Phase-sensitive operation is achieved by polarization filtering phase-locked signal/idler in a degenerate dual-pump vector parametric amplifier

Signal regeneration techniques for advanced modulation formats

We review recent results on all-optical regeneration of phase encoded signals based on phase sensitive amplification achieved by avoiding phase-to-amplitude conversion in order to facilitate the regeneration of amplitude/phase encoded (QAM) signals

Austrian Partners in Joint Ventures With Companies from CMEA Countries: Problems Today

International research institutes involved in comparative global studies are not normally involved in the education of students or their respective studies. However, this study on joint ventures between Austrian enterprises and companies from CMEA countries was undertaken by students of the Vienna University of Economics and Business Administration with the assistance of IIASA scientists. This exceptional example proves that such cooperation can be most successful and mutually beneficial. Cooperation can be summarized in that IIASA would provide methodological guidance, data, literature and organize a series of lectures on East-West cooperation with special emphasis on joint ventures. These lectures were given by experts from CMEA countries and Austria; each lecture being followed by a discussion not only on joint ventures but also on economic reform in CMEA countries and national business practice. Simultaneously, hypotheses, questionnaires and plans for interviews were developed jointly. The main objective of the study was to look at the problems that Western partners meet in the process of negotiating and operating joint ventures with Eastern companies. The study consisted of two parts: first, theoretical -- elaboration of methodology, basic concepts and hypothesis; and second, empirical -- revealing specific problems of joint venture creation and operation from the Austrian partner's viewpoint. This sample of managers from 20 companies represents half of the Austrian partners involved in joint ventures at the end of 1988. Normally joint ventures begin their activities within one year from the date of registration and stabilize after two to three years. Austria ranked second among the countries establishing joint ventures; ranked by the number of joint ventures created and by the share of joint venture contracts with CMEA among all contracts of industrial cooperation of the country -- 33.3%. The findings in this Working Paper do not always meet the assumptions; but this is a sign that joint ventures have used opportunities in some areas and found ways to overcome difficulties. Other important and promising issues which resulted from the study are: (1) Recognition and mutual understanding of two different systems and business environments was observed and considered vital by both East and West; (2) Willingness to cooperate and achieve synergy effects by Austrian partners and their readiness to share their experience and enter into another joint venture; (3) The lack of some goods and raw materials in CMEA countries combined with longer delivery times and the monopolistic position of suppliers on the domestic market, etc., turned out to be the main problems. (4) It can be generally stated that joint ventures are a good means of managerial know-how transfer. However, difficulties in managing East-West joint ventures can be found in two main areas: new methods and techniques (EDP and telecommunication) and in the functional area of personnel management. Although the management of joint venturers is not a particular problem. (5) The importance of a new type of "cooperation" management emerged from the study. It can be stated that based on the subjective views of the businessmen interviewed, the results are not far removed from other national research studies. Obviously the specific features of the countries play an important role but do not drastically change the shape of the problems. Criticism of the study can also be made. Some of the hypothesis and elaborated assumptions are not based on real data and facts from CMEA countries. The short period of study did not permit an extensive research of literature on and from CMEA countries. In addition, the number of managers who did not answer some questions was high thereby offering different subjective interpretations. However, the approach and the structure of this research could, in the future, serve as a constantly repeating check-up on East-Austrian economic ventures and their development. This study was the first of its kind carried out at IIASA and in the field. Even considering that only 20 out of 40 companies were studied, the results can be regarded as a barometer of Austrian partnership in ventures with CMEA countries

Cognitive function in people with and without freezing of gait in Parkinson’s disease

Freezing of gait (FOG) is common in people with Parkinson’s disease (PD) which is extremely debilitating. One hypothesis for the cause of FOG episodes is impaired cognitive control, however, this is still in debate in the literature. We aimed to assess a comprehensive range of cognitive tests in older adults and people with Parkinson’s with and without FOG and associate FOG severity with cognitive performance. A total of 227 participants took part in the study which included 80 healthy older adults, 81 people with PD who did not have FOG and 66 people with PD and FOG. A comprehensive battery of neuropsychological assessments tested cognitive domains of global cognition, executive function/attention, working memory, and visuospatial function. The severity of FOG was assessed using the new FOG questionnaire and an objective FOG severity score. Cognitive performance was compared between groups using an ANCOVA adjusting for age, gender, years of education and disease severity. Correlations between cognitive performance and FOG severity were analyzed using partial correlations. Cognitive differences were observed between older adults and PD for domains of global cognition, executive function/attention, and working memory. Between those with and without FOG, there were differences for global cognition and executive function/attention, but these differences disappeared when adjusting for covariates. There were no associations between FOG severity and cognitive performance. This study identified no significant difference in cognition between those with and without FOG when adjusting for covariates, particularly disease severity. This may demonstrate that complex rehabilitation programs may be undertaken in those with FOG

Bistatic LIDAR experiment proposed for the shuttle/tethered satellite system missions

A new experiment concept has been proposed for the shuttle/tethered satellite system missions, which can provide high resolution, global density mappings of certain ionospheric species. The technique utilizes bistatic LIDAR to take advantage of the unique dual platform configuration offered by these missions. A tuned, shuttle-based laser is used to excite a column of the atmosphere adjacent to the tethered satellite, while triangulating photometic detectors on the satellite are employed to measure the fluorescence from sections of the column. The fluorescent intensity at the detectors is increased about six decades over both ground-based and monostatic shuttle-based LIDAR sounding of the same region. In addition, the orbital motion of the Shuttle provides for quasi-global mapping unattainable with ground-based observations. Since this technique provides such vastly improved resolution on a synoptic scale, many important middle atmospheric studies, heretofore untenable, may soon be addressed

Preparation and optical properties of GA(x)IN(1-x)P alloys

The solution crystallization method was used to obtain Ga(z)In(1-x)P alloys for all values of x desired between zero and 1. The method of preparation makes it possible to crystallize the solid at a constant temperature. The points obtained by cathodoluminescence are nearly in straight lines. The optical absorption thresholds are confirmed in the results and make it possible to define the nature of the transitions except when x is in the neighborhood of 0.65. These determinations agree with those of Hilsum and Porteus (1968), but are not in agreement with those obtained by Lorenz et al, (1968)

Trapping and cooling single atoms with far-off resonance intracavity doughnut modes

We investigate cooling and trapping of single atoms inside an optical cavity using a quasi-resonant field and a far-off resonant mode of the Laguerre-Gauss type. The far-off resonant doughnut mode provides an efficient trapping in the case when it shifts the atomic internal ground and excited state in the same way, which is particularly useful for quantum information applications of cavity quantum electrodynamics (QED) systems. Long trapping times can be achieved, as shown by full 3-D simulations of the quasi-classical motion inside the resonator.Comment: 18 pages, 18 figures, RevTe