Ivan T. Lima

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—This paper shows how to use multiple importance sampling to study the performance of polarization-mode dispersion (PMD) compensators with a single differential group delay (DGD) element. We compute the eye opening penalty margin for compensated and uncompensated systems with outage probabilities of 10 5 or less with a fraction of the computational cost(More)
—We investigate the polarization evolution for both signal and noise in two 107-km recirculating loops with polarization dependent loss per round-trip of 0.35 dB and less than 0.1 dB, respectively. When the system is optimized, in the first case, both signal and noise are polarized, while in the second case, the signal tends to depolarize due to the noise.(More)
—This paper shows how to estimate errors in multi-canonical Monte Carlo (MMC) simulations using a transition-matrix method. MMC is a biasing Monte Carlo technique that allows one to compute the probability of rare events, such as the outage probability in optical-fiber communication systems. Since MMC is a Monte Carlo technique, it is subject to statistical(More)
—The authors have derived a receiver model that provides an explicit relationship between the factor and the optical signal-to-noise ratio (OSNR) in optical fiber communication systems for arbitrary pulse shapes, realistic receiver filters, and arbitrarily polarized noise. It is shown how the system performance depends on both the degree of polarization of(More)
—We evaluate the performance of single-section and three-section polarization-mode-dispersion (PMD) compensators using the biasing Monte Carlo methods of importance sampling (IS) and multicanonical Monte Carlo (MMC). We show that standard IS that biases only first-order PMD is insufficient to compute penalties in most compensated systems, while multiple IS(More)
—We analyze polarization mode dispersion (PMD) em-ulators comprised of a small number of sections of polarization-maintaining fibers with polarization scattering at the beginning of each section. Unlike previously studied devices, these emulators allow the emulation of a whole ensemble of fibers. We derive analytical expressions and determine two main(More)
—We propose a technique that uses Monte Carlo simulations with importance sampling and a reduced Stokes model to compute the probability density function of the factor and the outage probability for a channel in a long-haul wavelength-division -multiplexed optical-fiber transmission system due to the combination of polarization mode dispersion, polarization(More)
—We derive an explicit relationship between the factor and the optical signal-to-noise ratio in optical fiber transmission systems for an arbitrary pulse shape using an accurate receiver model under the assumption that the noise is unpolarized. We also define the enhancement factor and two other parameters that explicitly quantify the relative performance(More)
Recent experiments have demonstrated that the bit-error rate of an optical fiber communication system can vary widely due to the random nature of the polarization effects in the system. Using a newly developed receiver model, we show that the bit-error rate depends not only on the optical signal-to-noise ratio but also on the polarization states of the(More)
We developed an importance sampling based method that significantly speeds up the calculation of the diffusive reflectance due to ballistic and to quasi-ballistic components of photons scattered in turbid media: Class I diffusive reflectance. These components of scattered photons make up the signal in optical coherence tomography (OCT) imaging. We show that(More)