Spectral Phase Modulation
Mostrando 1-12 de 16 artigos, teses e dissertações.
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1. Sevoflurane preconditioning during myocardial ischemia-reperfusion reduces infarct size and preserves autonomic control of circulation in rats
ABSTRACT PURPOSE: To investigate the myocardial ischemia-reperfusion with sevoflurane anesthetic preconditioning (APC) would present beneficial effects on autonomic and cardiac function indexes after the acute phase of a myocardial ischemia-reperfusion. METHODS: Twenty Wistar rats were allocated in three groups: control (CON, n=10), myocardial infarction w
Acta Cir. Bras.. Publicado em: 2016-05
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2. All-optical cryptography through spectral amplitude and delay encoding
All-optical data encryption is a promising technology that could lead communication systems to an unprecedented degree of security. In this paper we use computer simulations to systematically investigate a new all-optical cryptography technique that is bit-rate independent and transparent to modulation formats. Encryption encompasses signal spectral slicing
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-12
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3. Sistemas CDMA ópticos coerentes baseados em codificação de fase espectral / Coherent optical CDMA systems based on spectral phase coding
In this work we perform a comprehensive analysis of a spectral phase-encoded time spreading optical code division multiple access (SPECTS-OCDMA) system. Despite being a numerical study, efforts were concentrated on the investigation of more realistic scenarios using as much information as possible from implemented test-beds in laboratories. In this context,
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 11/12/2012
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4. Optical cryptography through analog control of amplitude and delay of spectral slices: anlysis for NRZ and DQPSK signals. / Criptografia Ãptica mediante controle analÃgico da amplitude e do atraso de fatias espectrais: anÃlise para sinais NRZ e DQPSK.
This work investigates a technique to encrypt the optical signal for Transparent Optical Network, TON, in order to safeguard the confidentiality and guarantee the security of informations that are transmitted through the Telecommunications Network. The technique is assessed on the physical layer of the reference model for open systems interconnection, OSI, a
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 23/11/2012
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5. Geração de harmônicos de pulsos laser de femtossegundo pela técnica de conversão de frequência em capilares preenchidos com gases nobres / Harmonics generation of femtosecond laser pulses by the technique of frequency conversion in noble gas filled capillaries
O propósito principal desta tese foi a implementação e estudo da geração de pulsos laser de femtossegundos em comprimentos de onda curtos (ultravioleta profundo, ultravioleta de vácuo e ultravioleta extremo) pela técnica de conversão de frequência em capilar preenchido com gás nobre. Esta técnica de conversão de frequência tem feito diversas con
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 26/06/2012
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6. Caracterização espectral e avaliação de desempenho para formatos avançados de modulação digital optica em 40 Gb/s / Spectral characterization and performance evaluation for advanced digital optical modulation formats at 40 Gb/s
This work compares the performance of four feedforward carrier recovery architectures in coherent QPSK and 8-PSK receivers, with polarization multiplexing and differential decoding. We focused on the scenarios showing an SNR imbalance between orthogonal polarizations, as in PDL impaired systems. Using Monte Carlo simulations, we observed that the proposed jo
Publicado em: 2009
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7. AmplificaÃÃo Raman de pulsos curtos em fibras Ãpticas com ganho periÃdico / Raman amplification of short pulses in optical fibers with periodic gain
Optical Amplifiers amplify incident light through stimulated emission, the same mechanism which is used by lasers. Indeed, an optical amplifier, it is not but a laser without feedback. Its main ingredient is optical gain which is realized when the amplifier is under pumping process (optically or electrically) in order to cause population inversion at electro
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 01/04/2008
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8. Estudo de amplificadores parametricos para sistemas de comunicações opticas de altas taxas de transmissão / Study of parametric amplifiers for high bit rate optical communication systems
This thesis presents a theoretical and experimental study on fiber optics parametric amplifiers. For the double-pumped case, we show the performance of the amplifier in terms of spectral bandwidth and gain uniformity, both fundamental properties for WDM applications. By using short dispersion shifted fibers and highly non-linear fibers, we made parametric am
Publicado em: 2006
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9. Efeito Kerr magneto-óptico espectral e sperimagnetismo de filmes amorfos de terra rara-Co / Spectral magneto-optical Kerr effect and magnetism-speri of the films of amorphous rare earth-Co
We have observed the spectral behavior of the transverse magnetooptical Kerr effect (TMOKE) in thin films of rare earth - cobalt amorphous alloys for the visible and the near-ultraviolet ranges of spectrurn (wavelength fiom 325 nm up to 670 nm). The relative change of reflectivity has shown a maximum at the blue wavelength. We have concluded that this magnet
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 28/05/2001
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10. Optical Transmitter with Millimeter-wave Subcarrier
There is increasing need for high-speed fiberoptic links operating in the microwave and millimeter wave range for applications like cellular personal communication systems (PCS), high capacity distribution systems (HDTV, data, interactive multimedia), phased array, remote antennas, etc. The conventional methods of high frequency modulation at millimeter-wave
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 199706
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11. Subsistemas opticos para comunicação solitonica
This work invesligates oplical subsystems that can be used in solitonic communications. Several numerical simulations are presented, using the Mathemalica® programming language. Inilially, the non-linear oplical pulse propagalion is analyzed, using thefinite difference lime domain (FDTD) method. A pair of non-linear Schrõdinger equalions is solved simultan
Publicado em: 1996
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12. Mode-locking de um laser de corante pulsado bombeado por lampada
In this work, we describe the construction of a CPM Dye Laser Flashlamp-Pumped with group velocity dispersion compensation and self phase modulation balancing, based on a comercial Dye Laser, Chromatrix, CMX-4 model. We obtain pulses at 596.5 nm with time duration FWHM of 896 fs with 250KW of peak power and spectral line width of 1.5nm
Publicado em: 1994