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Papers by Alberto Paradisi

Anais do 2002 International Telecommunications Symposium, 2002

We carry out numerical simulations to compare the impact of the fiber nonlinear effects on transm... more We carry out numerical simulations to compare the impact of the fiber nonlinear effects on transmission of 40 and 80 WDM channels modulated at 10 Gb/s, for three different fiber types, standard single mode fiber, large effective area NZDSF, and reduced dispersion slope NZDSF. By comparing the results with single channel transmission, we explain the contribution of the main nonlinear effects to the power penalties obtained.

Anais do 2002 International Telecommunications Symposium

Journal of Microwaves, Optoelectronics and Electromagnetic Applications, 2013

Optics Express, 2011

For asynchronous sampled systems such as Polarization Division Multiplexed Quadrature Phase Shift... more For asynchronous sampled systems such as Polarization Division Multiplexed Quadrature Phase Shift Keying, (PDM-QPSK), phase and frequency of the sampling clock is typically not synchronized to the data symbols. Therefore, timing adjustment, so called clock recovery and interpolation, must be performed in digital domain prior to signal demodulation in order to avoid cycle slips. For the first time, the impact of first order PMD, (DGD), is experimentally investigated and quantified for 112 Gb/s PDM-QPSK signal. We experimentally show that the combined effect of polarization mixing and first order PMD can significantly affect the performance of the timing error detector gain, even for moderate values leading to system outage. We propose and experimentally demonstrate a novel digital adaptive timing error detector is robust to polarization mixing and DGD. The proposed timing error detector algorithm combines the Gardner timing error detector algorithm with an adaptive structure based on gradient method.

Optical Fiber Technology, 2000

We analyze the spectral asymmetry due to stimulated Raman scattering in repeaterless and amplifie... more We analyze the spectral asymmetry due to stimulated Raman scattering in repeaterless and amplified links of WDM optical communication systems. It is shown that this effect depends strongly on the sign of the dispersion parameter and dispersion slope of the fiber. Criteria for the equalization of the WDM spectra are presented.

Microwave and Optical Technology Letters, 2012

ABSTRACT Crosstalk penalties in flexible grid networks with mixed rates lead to system degradatio... more ABSTRACT Crosstalk penalties in flexible grid networks with mixed rates lead to system degradation due to add/drop in-band residual power or nonuniform channel grid allocation. These penalties are quantified for 112G-DP-QPSK test channel with 10G-OOK, 40G-DQPSK, 112G-DP-QPSK, and 224G-DP-16-QAM simultaneous optical transmission. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:119–122, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27269

Photonics Technology Letters, IEEE, Mar 1, 1999

We present an experimental observation of modulation instability (MI) impairments on a two-channe... more We present an experimental observation of modulation instability (MI) impairments on a two-channel wavelength-division-multiplexed (WDM) system at 2.5 Gb/s per channel repeaterless link comprising 100 km of dispersion shifted fiber. When the channel spacing is close to the modulation instability frequency, channel depletion due to four-wave-mixing (FWM) interactions is resonantly enhanced and becomes the main source of system performance degradation. Numerical simulations agree well with the experiment and ...

Anais de XXX Simpósio Brasileiro de Telecomunicações

Anais de XXIX Simpósio Brasileiro de Telecomunicações

Resumo-Neste trabalho é apresentada uma transmissão óptica experimental de 3,58 TB/s utilizando 3... more Resumo-Neste trabalho é apresentada uma transmissão óptica experimental de 3,58 TB/s utilizando 32 canais modulados a 112 Gb/s com o uso do formato de modulação NRZ-DP-QPSK e detecção coerente. Os efeitos da filtragem óptica imposta pelos ROADMs em redes ópticas são analisados. Um alcance máximo de 4050 km é obtido em uma estrutura de propagação baseada em fibras de sílica pura e EDFAs como estrutura de amplificação. Palavras-Chave-Sistemas ópticos de alta velocidade, eficiência espectral, redes ópticas, filtragem óptica, formatos de modulação.

J Opt Netw, 2007

Plug and play optical (PPO) nodes may be used to facilitate the deployment of optical networks. P... more Plug and play optical (PPO) nodes may be used to facilitate the deployment of optical networks. PPO nodes must be able to learn about the signal propagation properties of the surrounding optical fibers and make their wavelengthrouting decisions based on the collected data. We discuss what are the open challenges that must be overcome to provide optical networking solutions based on cost-effective PPO nodes. Three possible PPO node hardware architectures with trade-offs in complexity, cost, and functionality are presented along with their built-in fiber characterization techniques.

Conference Proceedings LEOS'96 9th Annual Meeting IEEE Lasers and Electro-Optics Society, 1996

This paper reports the modelling of tapered fibre filters using the beam propagation method (BPM)... more This paper reports the modelling of tapered fibre filters using the beam propagation method (BPM) for solving the corresponding propagation equation. The results of the numerical approach are compared with the experiments by using simulation parameters related to the fabrication process

1999 SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference, 1999

Abstract We analyze the spectral energy redistribution among Wavelength Division Multiplexed (WDM... more Abstract We analyze the spectral energy redistribution among Wavelength Division Multiplexed (WDM) channels due to nonlinear interactions in low dispersion fibers. We present numerical results on a 4 channel at 10 Gb/s per channel system with launched power levels appropriate to overcome very long haul links of dispersion shifted fiber without repeaters. A characteristic spectral shaping is observed where the central channels are less (more) depleted relative to the outermost channels in the normal (anomalous) dispersion ...

IEEE Journal of Quantum Electronics, 1993

We have analyzed the static performance of a wavelength converter obtained by a multisection DBR ... more We have analyzed the static performance of a wavelength converter obtained by a multisection DBR laser with a saturable absorber between two gain sections. For this device an optical input signal at one given wavelength is converted into an output signal at the lasing wavelength. The performances are evaluated in terms of conversion efficiency, suppression ratio and minimum input power needed for wavelength conversion. It is shown that a proper choice of the injected signal wavelength with respect to the lasing wavelength enhances the conversion efficiency and the suppression ratio and reduces the switching power. The performance can be enhanced also by increasing the electrical current applied to the first gain section, provided that the second gain section is biased above the transparency level. We have shown that reduction of the front facet reflectivity results in a dramatic increase for the conversion efficiency. The sensitivity to the electrical bias condition and to the resonant condition of the injected signal with respect to the cavity have also been investigated.

The switch-off time in a dispersive bistable laser amplifier is usually considered to be limited ... more The switch-off time in a dispersive bistable laser amplifier is usually considered to be limited by the inverse of the effective carrier lifetime, the switch-off can be faster with the laser diode operating very near threshold. On the other hand, optical bistability (OB) has also been found recently in optically injection-locked semiconductor lasers; in this case however the dynamic properties

Transparent Optical …, Jun 1, 2006

Plug and play optical (PPO) nodes may be used to facilitate the deployment of optical networks. P... more Plug and play optical (PPO) nodes may be used to facilitate the deployment of optical networks. PPO nodes must be able to learn about the signal propagation properties of the surrounding optical fibers and make their wavelength routing decisions based on the collected data. This paper discusses what are the open challenges that must be overcome to provide cost effective and performing ad hoc networking solutions based on PPO nodes.

Quantum Electronics Ieee Journal of, Mar 1, 1991

In this paper, we have examined and compared the various numerical models commonly used in the li... more In this paper, we have examined and compared the various numerical models commonly used in the literature for the simulation of bistable laser diodes with saturable absorbers. The models have heen improved through consideration of the coupling and the interface effect between the pumped and absorbing regions. Comparisons to experimental results are presented and discussed.

Anais do 2002 International Telecommunications Symposium, 2002

We carry out numerical simulations to compare the impact of the fiber nonlinear effects on transm... more We carry out numerical simulations to compare the impact of the fiber nonlinear effects on transmission of 40 and 80 WDM channels modulated at 10 Gb/s, for three different fiber types, standard single mode fiber, large effective area NZDSF, and reduced dispersion slope NZDSF. By comparing the results with single channel transmission, we explain the contribution of the main nonlinear effects to the power penalties obtained.

Anais do 2002 International Telecommunications Symposium

Journal of Microwaves, Optoelectronics and Electromagnetic Applications, 2013

Optics Express, 2011

For asynchronous sampled systems such as Polarization Division Multiplexed Quadrature Phase Shift... more For asynchronous sampled systems such as Polarization Division Multiplexed Quadrature Phase Shift Keying, (PDM-QPSK), phase and frequency of the sampling clock is typically not synchronized to the data symbols. Therefore, timing adjustment, so called clock recovery and interpolation, must be performed in digital domain prior to signal demodulation in order to avoid cycle slips. For the first time, the impact of first order PMD, (DGD), is experimentally investigated and quantified for 112 Gb/s PDM-QPSK signal. We experimentally show that the combined effect of polarization mixing and first order PMD can significantly affect the performance of the timing error detector gain, even for moderate values leading to system outage. We propose and experimentally demonstrate a novel digital adaptive timing error detector is robust to polarization mixing and DGD. The proposed timing error detector algorithm combines the Gardner timing error detector algorithm with an adaptive structure based on gradient method.

Optical Fiber Technology, 2000

We analyze the spectral asymmetry due to stimulated Raman scattering in repeaterless and amplifie... more We analyze the spectral asymmetry due to stimulated Raman scattering in repeaterless and amplified links of WDM optical communication systems. It is shown that this effect depends strongly on the sign of the dispersion parameter and dispersion slope of the fiber. Criteria for the equalization of the WDM spectra are presented.

Microwave and Optical Technology Letters, 2012

ABSTRACT Crosstalk penalties in flexible grid networks with mixed rates lead to system degradatio... more ABSTRACT Crosstalk penalties in flexible grid networks with mixed rates lead to system degradation due to add/drop in-band residual power or nonuniform channel grid allocation. These penalties are quantified for 112G-DP-QPSK test channel with 10G-OOK, 40G-DQPSK, 112G-DP-QPSK, and 224G-DP-16-QAM simultaneous optical transmission. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:119–122, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27269

Photonics Technology Letters, IEEE, Mar 1, 1999

We present an experimental observation of modulation instability (MI) impairments on a two-channe... more We present an experimental observation of modulation instability (MI) impairments on a two-channel wavelength-division-multiplexed (WDM) system at 2.5 Gb/s per channel repeaterless link comprising 100 km of dispersion shifted fiber. When the channel spacing is close to the modulation instability frequency, channel depletion due to four-wave-mixing (FWM) interactions is resonantly enhanced and becomes the main source of system performance degradation. Numerical simulations agree well with the experiment and ...

Anais de XXX Simpósio Brasileiro de Telecomunicações

Anais de XXIX Simpósio Brasileiro de Telecomunicações

Resumo-Neste trabalho é apresentada uma transmissão óptica experimental de 3,58 TB/s utilizando 3... more Resumo-Neste trabalho é apresentada uma transmissão óptica experimental de 3,58 TB/s utilizando 32 canais modulados a 112 Gb/s com o uso do formato de modulação NRZ-DP-QPSK e detecção coerente. Os efeitos da filtragem óptica imposta pelos ROADMs em redes ópticas são analisados. Um alcance máximo de 4050 km é obtido em uma estrutura de propagação baseada em fibras de sílica pura e EDFAs como estrutura de amplificação. Palavras-Chave-Sistemas ópticos de alta velocidade, eficiência espectral, redes ópticas, filtragem óptica, formatos de modulação.

J Opt Netw, 2007

Plug and play optical (PPO) nodes may be used to facilitate the deployment of optical networks. P... more Plug and play optical (PPO) nodes may be used to facilitate the deployment of optical networks. PPO nodes must be able to learn about the signal propagation properties of the surrounding optical fibers and make their wavelengthrouting decisions based on the collected data. We discuss what are the open challenges that must be overcome to provide optical networking solutions based on cost-effective PPO nodes. Three possible PPO node hardware architectures with trade-offs in complexity, cost, and functionality are presented along with their built-in fiber characterization techniques.

Conference Proceedings LEOS'96 9th Annual Meeting IEEE Lasers and Electro-Optics Society, 1996

This paper reports the modelling of tapered fibre filters using the beam propagation method (BPM)... more This paper reports the modelling of tapered fibre filters using the beam propagation method (BPM) for solving the corresponding propagation equation. The results of the numerical approach are compared with the experiments by using simulation parameters related to the fabrication process

1999 SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference, 1999

Abstract We analyze the spectral energy redistribution among Wavelength Division Multiplexed (WDM... more Abstract We analyze the spectral energy redistribution among Wavelength Division Multiplexed (WDM) channels due to nonlinear interactions in low dispersion fibers. We present numerical results on a 4 channel at 10 Gb/s per channel system with launched power levels appropriate to overcome very long haul links of dispersion shifted fiber without repeaters. A characteristic spectral shaping is observed where the central channels are less (more) depleted relative to the outermost channels in the normal (anomalous) dispersion ...

IEEE Journal of Quantum Electronics, 1993

We have analyzed the static performance of a wavelength converter obtained by a multisection DBR ... more We have analyzed the static performance of a wavelength converter obtained by a multisection DBR laser with a saturable absorber between two gain sections. For this device an optical input signal at one given wavelength is converted into an output signal at the lasing wavelength. The performances are evaluated in terms of conversion efficiency, suppression ratio and minimum input power needed for wavelength conversion. It is shown that a proper choice of the injected signal wavelength with respect to the lasing wavelength enhances the conversion efficiency and the suppression ratio and reduces the switching power. The performance can be enhanced also by increasing the electrical current applied to the first gain section, provided that the second gain section is biased above the transparency level. We have shown that reduction of the front facet reflectivity results in a dramatic increase for the conversion efficiency. The sensitivity to the electrical bias condition and to the resonant condition of the injected signal with respect to the cavity have also been investigated.

The switch-off time in a dispersive bistable laser amplifier is usually considered to be limited ... more The switch-off time in a dispersive bistable laser amplifier is usually considered to be limited by the inverse of the effective carrier lifetime, the switch-off can be faster with the laser diode operating very near threshold. On the other hand, optical bistability (OB) has also been found recently in optically injection-locked semiconductor lasers; in this case however the dynamic properties

Transparent Optical …, Jun 1, 2006

Plug and play optical (PPO) nodes may be used to facilitate the deployment of optical networks. P... more Plug and play optical (PPO) nodes may be used to facilitate the deployment of optical networks. PPO nodes must be able to learn about the signal propagation properties of the surrounding optical fibers and make their wavelength routing decisions based on the collected data. This paper discusses what are the open challenges that must be overcome to provide cost effective and performing ad hoc networking solutions based on PPO nodes.

Quantum Electronics Ieee Journal of, Mar 1, 1991

In this paper, we have examined and compared the various numerical models commonly used in the li... more In this paper, we have examined and compared the various numerical models commonly used in the literature for the simulation of bistable laser diodes with saturable absorbers. The models have heen improved through consideration of the coupling and the interface effect between the pumped and absorbing regions. Comparisons to experimental results are presented and discussed.