Optical communications applications of ultra-long Raman fiber lasers

Recent work on ultra-long Raman fiber lasers has shown that it is possible to create quasi-lossless transmission conditions in fiber spans long enough to be considered for high speed optical communications. This paper reviews how quasi-lossless transmission conditions are reached and presents experimental results of 40Gb/s transmission in a quasi lossless system. The performance is compared with a conventional EDFA based system.

Recent developments in all-optical nonlinear signal processing for fiber-optic communications

All-optical data processing is expected to play a major role in future optical communications. Nonlinear effects in optical fibers have attractive applications in optical signal processing. In this paper, we review our recent advances in developing all-optical processing techniques at high speed based on optical fiber nonlinearities.

Adaptive electrical signal post-processing in optical communications systems

Improving bit error rates in optical communication systems is a difficult and important problem. The error correction must take place at high speed and be extremely accurate. We show the feasibility of using hardware implementable machine learning techniques. This may enable some error correction at the speed required.

Information-theory analysis of skewed coding for suppression of pattern-dependent errors in digital communications

We present information-theory analysis of the tradeoff between bit-error rate improvement and the data-rate loss using skewed channel coding to suppress pattern-dependent errors in digital communications. Without loss of generality, we apply developed general theory to the particular example of a high-speed fiber communication system with a strong patterning effect. © 2007 IEEE.

Physics-inspired methods for networking and communications

Advances in statistical physics relating to our understanding of large-scale complex systems have recently been successfully applied in the context of communication networks. Statistical mechanics methods can be used to decompose global system behavior into simple local interactions. Thus, large-scale problems can be solved or approximated in a distributed manner with iterative lightweight local messaging. This survey discusses how statistical physics methodology can provide efficient solutions to hard network problems that are intractable by classical methods. We highlight three typical examples in the realm of networking and communications. In each case we show how a fundamental idea of statistical physics helps solve the problem in an efficient manner. In particular, we discuss how to perform multicast scheduling with message passing methods, how to improve coding using the crystallization process, and how to compute optimal routing by representing routes as interacting polymers.

Foreword to the special issue on European conference on optical communications (ECOC 2014)

The articles in this special section were presented at the European Conference on Optical Communications (ECOC) that was held on on 21???25 September 2014 in Cannes, France

Intellectual Communications and Contemporarly Technologies Alternatives of the Science Libraries

(Summary of: Varbanova-Dencheva, K. Intellectual communications and contemporarly technologies. Alternatives of the science libraries. Sofia, Marin Drinov academic publishing house. 2003, 114p. ) The new technologies and the globalization are the factors which have brought essential changes in human society and its environment. The unceasing dynamic changes imposed new strategies for survival and prosperity of institutions and people in the new conditions. The spheres with greatest potential for achieving competition priority are compatible to the fastness of research results implementation in each field of human activity. The extended knowledge requires narrower specialization as well as interdisciplinarity to solve the arising problems. The new research fields and trends are a synthesis of science and high technologies determined by the new discoveries. The present study aims at finding answers to the questions about the place of science library in the dynamic restructuring of research environment. The necessity of transformation of the scientific library’s genetically set functions from a guardian of the achieved knowledge to an active participant in the creation of new knowledge is a natural consequence of the processes and tendencies of the social medium. The priorities of Europe and USA for intensive creation of knowledge economics are at the first place and this requires intensification of that research an integral part of which are the new communications realized at a new technological level.

Multi-wavelength source using low drive-voltage amplitude modulators for optical communications

A simple and cost-effective technique for generating a flat, square-shaped multi-wavelength optical comb with 42.6 GHz line spacing and over 0.5 THz of total bandwidth is presented. A detailed theoretical analysis is presented, showing that using two concatenated modulators driven with voltages of 3.5 Vp are necessary to generate 11 comb lines with a flatness below 2dB. This performance is experimentally demonstrated using two cascaded Versawave 40 Gbit/s low drive voltage electro-optic polarisation modulators, where an 11 channel optical comb with a flatness of 1.9 dB and a side-mode-suppression ratio (SMSR) of 12.6 dB was obtained.

Multi-band carrier-less amplitude and phase modulation for bandlimited visible light communications systems

Visible light communications is a technology with enormous potential for a wide range of applications within next generation transmission and broadcasting technologies. VLC offers simultaneous illumination and data communications by intensity modulating the optical power emitted by LEDs operating in the visible range of the electromagnetic spectrum (~370-780 nm). The major challenge in VLC systems to date has been in improving transmission speeds, considering the low bandwidths available with commercial LED devices. Thus, to improve the spectral usage, the research community has increasingly turned to advanced modulation formats such as orthogonal frequency-division multiplexing. In this article we introduce a new modulation scheme into the VLC domain; multiband carrier-less amplitude and phase modulation (m-CAP) and describe in detail its performance within the context of bandlimited systems.

"Trade creep" and implications of the Transatlantic Trade and Investment Partnership Agreement for the United Kingdom National Health Service

The ambitious and comprehensive Transatlantic Trade and Investment Partnership Agreement (TTIP/TAFTA) agreement between the European Union and United States is now being negotiated and may have far-reaching consequences for health services. The agreement extends to government procurement, investment, and further regulatory cooperation. In this article, we focus on the United Kingdom National Health Service and how these negotiations can limit policy space to change policies and to regulate in relation to health services, pharmaceuticals, medical devices, and health industries. The negotiation of TTIP/TAFTA has the potential to "harmonize" more corporate-friendly regulation, resulting in higher costs and loss of policy space, an example of "trade creep" that potentially compromises health equity, public health, and safety concerns across the Atlantic.