ABSTRACT The popular single-carrier QPSK modulation format is compared with 8PSK BICM and TCM sch... more ABSTRACT The popular single-carrier QPSK modulation format is compared with 8PSK BICM and TCM schemes in 100 Gbps optical links in linear and nonlinear regime, with or without inline dispersion compensation.
Asia Communications and Photonics Conference, 2012
ABSTRACT An accurate and low complexity blind adaptive chromatic dispersion compensation and esti... more ABSTRACT An accurate and low complexity blind adaptive chromatic dispersion compensation and estimation algorithm for coherent optical systems is proposed and experimentally validated. The method is based on a Frequency Domain Equalizer, a low complexity Butterfly Time Domain Equalizer and an Optical Performance Monitoring in a loop configuration.
Coherent detection has recently allowed the adoption of high-order modulation formats in single-c... more Coherent detection has recently allowed the adoption of high-order modulation formats in single-carrier optical systems where a simple feed-forward equalizer, in proper configuration, is able to perfectly compensate for fiber linear impairments, such as group velocity dispersion and polarization-mode dispersion. In this letter, the blind update of the equalizer taps is investigated with reference to a 16-ary quadrature amplitude modulation
Global Telecommunications Conference, . GLOBECOM . IEEE, 2010
In coherent optical systems, the phase noise due to transmit and receive lasers has a significant... more In coherent optical systems, the phase noise due to transmit and receive lasers has a significant impact on the receiver performance - the sensitivity to phase noise and the capability of electronic processing to compensate for its effects are reduced for increasing lasers'' linewidths. However, a detailed analysis of the effects of phase noise on the system performance cannot leave
Sub-Nyquist time frequency packing technique was demonstrated for the first time in a super-chann... more Sub-Nyquist time frequency packing technique was demonstrated for the first time in a super-channel field trial transmission over long-haul distances. The technique allows a limited spectral occupancy even with low order modulation formats. The transmission was successfully performed on a deployed Australian link between Sydney and Melbourne which included 995 km of uncompensated SMF with coexistent traffic. 40 and 100 Gb/s co-propagating channels were transmitted together with the super-channel in a 50 GHz ITU-T grid without additional penalty. The super-channel consisted of eight sub-channels with low-level modulation format, i.e. DP-QPSK, guaranteeing better OSNR robustness and reduced complexity with respect to higher order formats. At the receiver side, coherent detection was used together with iterative maximum-a-posteriori (MAP) detection and decoding. A 975 Gb/s DP-QPSK super-channel was successfully transmitted between Sydney and Melbourne within four 50GHz WSS channels (20...
IFIP International Federation for Information Processing, 2005
In high-speed optical transmission systems, one of the most challenging impairments is represente... more In high-speed optical transmission systems, one of the most challenging impairments is represented by the signal distortions produced by polarization-mode dispersion (PMD). In this paper, we analyze the limits of electronic compensation schemes, in the form of maximum-likelihood sequence detection receivers. With a constraint on the front-end processing after photo-detection, we compute the signal statistics necessary to implement this strategy. The receiver adaptivity is also discussed. The relevant performance is analyzed by means of computer simulations and accurate analytical performance bounds, and compared with the performance of all-optical compensators and decision-feedback equalizers. A significant performance loss with respect to optical compensation is observed for large values of the differential group delay (DGD) showing that, after the non reversible transformation operated by the photo-detector, it is not possible to effectively cope with the PMD-induced impairments.
39th European Conference and Exhibition on Optical Communication (ECOC 2013), 2000
ABSTRACT We investigate the time-frequency packing technique on long-haul optical links in order ... more ABSTRACT We investigate the time-frequency packing technique on long-haul optical links in order to increase the spectral efficiency. This solution is compared to high-order formats at equal bit or baud rate, demonstrating that higher spectral efficiency can be more effectively reached.
2013 IEEE Global Communications Conference (GLOBECOM), 2013
ABSTRACT We consider realistic long-haul optical links, where nonlinear effects represent the mai... more ABSTRACT We consider realistic long-haul optical links, where nonlinear effects represent the main impairment, and investigate the application of time-frequency packing with low-order constellations as a the most viable solution to increase the spectral efficiency. We will see that this technique allows to overcome the relevant theoretical and technological issues related to this spectral efficiency increase and is more effective than the simple adoption of high-order modulation formats which are more sensitive to nonlinear effects.
We demonstrate that, by using maximum-likelihood sequence detection with proper branch metrics an... more We demonstrate that, by using maximum-likelihood sequence detection with proper branch metrics and a proper front end, it is possible to implement multilevel optical transmissions insensitive to GVD and PMD.
2010 IEEE International Conference on Communications, 2010
ABSTRACT Orthogonal frequency division multiplexing (OFDM) and single-carrier (SC) data transmiss... more ABSTRACT Orthogonal frequency division multiplexing (OFDM) and single-carrier (SC) data transmission are compared as potential candidates for the next generation coherent long-haul 100 Gbps optical communication systems. The comparison takes into account impairments either general or mainly related to coherent detection, e.g., group velocity dispersion (GVD), polarization mode dispersion (PMD), non-linear effects, phase noise due to transmit and receive lasers, uncompensated frequency offset, other synchronization aspects, overall complexity, power and spectral efficiency, technological constraints.
ABSTRACT The popular single-carrier QPSK modulation format is compared with 8PSK BICM and TCM sch... more ABSTRACT The popular single-carrier QPSK modulation format is compared with 8PSK BICM and TCM schemes in 100 Gbps optical links in linear and nonlinear regime, with or without inline dispersion compensation.
Asia Communications and Photonics Conference, 2012
ABSTRACT An accurate and low complexity blind adaptive chromatic dispersion compensation and esti... more ABSTRACT An accurate and low complexity blind adaptive chromatic dispersion compensation and estimation algorithm for coherent optical systems is proposed and experimentally validated. The method is based on a Frequency Domain Equalizer, a low complexity Butterfly Time Domain Equalizer and an Optical Performance Monitoring in a loop configuration.
Coherent detection has recently allowed the adoption of high-order modulation formats in single-c... more Coherent detection has recently allowed the adoption of high-order modulation formats in single-carrier optical systems where a simple feed-forward equalizer, in proper configuration, is able to perfectly compensate for fiber linear impairments, such as group velocity dispersion and polarization-mode dispersion. In this letter, the blind update of the equalizer taps is investigated with reference to a 16-ary quadrature amplitude modulation
Global Telecommunications Conference, . GLOBECOM . IEEE, 2010
In coherent optical systems, the phase noise due to transmit and receive lasers has a significant... more In coherent optical systems, the phase noise due to transmit and receive lasers has a significant impact on the receiver performance - the sensitivity to phase noise and the capability of electronic processing to compensate for its effects are reduced for increasing lasers'' linewidths. However, a detailed analysis of the effects of phase noise on the system performance cannot leave
Sub-Nyquist time frequency packing technique was demonstrated for the first time in a super-chann... more Sub-Nyquist time frequency packing technique was demonstrated for the first time in a super-channel field trial transmission over long-haul distances. The technique allows a limited spectral occupancy even with low order modulation formats. The transmission was successfully performed on a deployed Australian link between Sydney and Melbourne which included 995 km of uncompensated SMF with coexistent traffic. 40 and 100 Gb/s co-propagating channels were transmitted together with the super-channel in a 50 GHz ITU-T grid without additional penalty. The super-channel consisted of eight sub-channels with low-level modulation format, i.e. DP-QPSK, guaranteeing better OSNR robustness and reduced complexity with respect to higher order formats. At the receiver side, coherent detection was used together with iterative maximum-a-posteriori (MAP) detection and decoding. A 975 Gb/s DP-QPSK super-channel was successfully transmitted between Sydney and Melbourne within four 50GHz WSS channels (20...
IFIP International Federation for Information Processing, 2005
In high-speed optical transmission systems, one of the most challenging impairments is represente... more In high-speed optical transmission systems, one of the most challenging impairments is represented by the signal distortions produced by polarization-mode dispersion (PMD). In this paper, we analyze the limits of electronic compensation schemes, in the form of maximum-likelihood sequence detection receivers. With a constraint on the front-end processing after photo-detection, we compute the signal statistics necessary to implement this strategy. The receiver adaptivity is also discussed. The relevant performance is analyzed by means of computer simulations and accurate analytical performance bounds, and compared with the performance of all-optical compensators and decision-feedback equalizers. A significant performance loss with respect to optical compensation is observed for large values of the differential group delay (DGD) showing that, after the non reversible transformation operated by the photo-detector, it is not possible to effectively cope with the PMD-induced impairments.
39th European Conference and Exhibition on Optical Communication (ECOC 2013), 2000
ABSTRACT We investigate the time-frequency packing technique on long-haul optical links in order ... more ABSTRACT We investigate the time-frequency packing technique on long-haul optical links in order to increase the spectral efficiency. This solution is compared to high-order formats at equal bit or baud rate, demonstrating that higher spectral efficiency can be more effectively reached.
2013 IEEE Global Communications Conference (GLOBECOM), 2013
ABSTRACT We consider realistic long-haul optical links, where nonlinear effects represent the mai... more ABSTRACT We consider realistic long-haul optical links, where nonlinear effects represent the main impairment, and investigate the application of time-frequency packing with low-order constellations as a the most viable solution to increase the spectral efficiency. We will see that this technique allows to overcome the relevant theoretical and technological issues related to this spectral efficiency increase and is more effective than the simple adoption of high-order modulation formats which are more sensitive to nonlinear effects.
We demonstrate that, by using maximum-likelihood sequence detection with proper branch metrics an... more We demonstrate that, by using maximum-likelihood sequence detection with proper branch metrics and a proper front end, it is possible to implement multilevel optical transmissions insensitive to GVD and PMD.
2010 IEEE International Conference on Communications, 2010
ABSTRACT Orthogonal frequency division multiplexing (OFDM) and single-carrier (SC) data transmiss... more ABSTRACT Orthogonal frequency division multiplexing (OFDM) and single-carrier (SC) data transmission are compared as potential candidates for the next generation coherent long-haul 100 Gbps optical communication systems. The comparison takes into account impairments either general or mainly related to coherent detection, e.g., group velocity dispersion (GVD), polarization mode dispersion (PMD), non-linear effects, phase noise due to transmit and receive lasers, uncompensated frequency offset, other synchronization aspects, overall complexity, power and spectral efficiency, technological constraints.
Uploads