Applications of optical processing for improving ERTS data, volume 1

Application of optically diagnosed noise information toward development of filtering subroutines for improvement of digital sensing data tape quality - Vol.

Management, processing and dissemination of sensory data for the Earth Resource Technology Satellite

Data center for management, processing, and dissemination of photographic products generated by ERT

Theoretical Insights into the Impact of Coherent and Incoherent Crosstalk on Optical DPSK Signals

WOS:000283247600001 (Nº de Acesso Web of Science)“Prémio Científico ISCTE-IUL 2011”This paper provides new theoretical insights into the properties of direct detection differential phase-shift keying (DPSK) signals impaired by coherent and incoherent crosstalk. Coherent crosstalk is due to multiple replicas originated while a data signal is routed through an optical network, whereas the source of incoherent crosstalk resides on the interference from other DPSK signals. A special emphasize has been put on modeling the multipath coherent crosstalk, with analytical expressions being derived and presented for both the moment generating function of the decision variable and the average error probability. A rigorous analysis, capable of dealing with arbitrary filtering, is also presented, which is used afterwards to assess the accuracy of the analytical formulas. A detailed comparison with incoherent crosstalk is also performed. Using also an exact treatment for this type of crosstalk it is shown that for low OSNR penalties the coherent crosstalk leads, in some circumstances, to slightly worse results than the incoherent one, but this situation is reversed when the total crosstalk level and the number of interferers increase

Quantifying the influence of crosstalk-crosstalk beat noise in optical DPSK systems

In-band crosstalk, due to multiple interferers, is one of the most severe physical impairments in optical transparent networks. Differential phase-shift keying (DPSK) has been identified as an attractive modulation scheme to be used in such environments due to its robustness to in-band crosstalk. At the output of the receiver photodiode, which is assumed to behave as a square law device, the in-band crosstalk interferes with the signal, resulting in the signal-crosstalk beat noise and the crosstalk-crosstalk beat noise. Usually this last noise contribution is neglected, but in this paper the impact of the crosstalk-crosstalk beating terms is considered and quantified. It is concluded that these terms have a growing influence as the optical signal-to-noise ratio (OSNR) value increases.info:eu-repo/semantics/acceptedVersio

MISCELLANEOUS SOUTH EAST ASIAN CUCURBIT NEWS II

DE WILDE, W.J.J.O & DUYFJES, B.E.E. 2009. Miscellaneous South East Asian Cucurbit news II. Reinwardtia 12(5): 405–414. — This paper contains corrections, additions, new taxa, or new records in several genera, which became apparent since previous publications by the authors in these genera.(1) Diplocyclos (Endl.) Post & Kuntze: a new variety in Diplocyclos palmatus (L.) C. Jeffrey(2). Pilogyne Schrad.: re-instatement of this genus name for SE Asian species formerly in Zehneria Endl., with the description of a new species from the Philippines(3) Thladiantha Bunge: Thladiantha nudiflora Forbes & Hemsley, new for Malesia(4) Trichosanthes L.: three subspecies in Trichosanthes tricuspidata Lour

Implications of in-band crosstalk on DQPSK Signals in ROADM-based metropolitan optical networks

Metropolitan optical networks can be designed to transport a multitude of signals with different bit rates and modulations formats. In this way, in-band crosstalk signals, originated from imperfect isolation inside ROADM (Reconfigurable Optical Add and Drop Multiplexer)-based optical nodes, will potentially have a different modulation format than the primary signal. In this paper, the origin of in-band crosstalk in a typical ROADM is analysed and its impact on differential quadrature phase-shift keying (DQPSK) signals is assessed through an analytical formalism based on the moment generating function (MGF) of the receiver decision variable. Various scenarios are analysed including the case of multiple interfering terms with different modulation formats, namely the on-off keying (OOK). It is concluded that the OOK interferer is more detrimental than the DQPSK interferer for DQPSK systems, or than the differential phase-shift keying (DPSK) interferer for DPSK systems.info:eu-repo/semantics/publishedVersio

On Minimal N=4 Topological Strings And The (1,k) Minimal Bosonic String

In this paper we consider tree-level scattering in the minimal N=4 topological string and show that a large class of N-point functions can be recast in terms of corresponding amplitudes in the (1,k) minimal bosonic string. This suggests a non-trivial relation between the minimal N=4 topological strings, the (1,k) minimal bosonic strings and their corresponding ADE matrix models. This relation has interesting and far-reaching implications for the topological sector of six-dimensional Little String Theories.Comment: lanlmac, 30 pages; v3 minor revisions, version published in JHE