Filipe M. Ferreira

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The complexities of common equalizer schemes are analytically analyzed in this paper in terms of complex multiplications per bit. Based on this approach we compare the complexity of mode-division multiplexed digital signal processing algorithms with different numbers of multiplexed modes in terms of modal dispersion and distance. It is found that training(More)
In this paper, we numerically investigate the impact of polarisation mode dispersion on the efficiency of compensation of nonlinear transmission penalties for systems employing one of more inline phase conjugation devices. We will show that reducing the spacing between phase conjugations allows for significantly improved performance in the presence(More)
In this paper, we investigate the design of few-mode fibers (FMFs) guiding 4 to 12 non-degenerate linearly polarized (LP) modes with low differential mode delay (DMD) over the C-band, suitable for long-haul transmission. The refractive index profile considered is composed by a graded-core with a cladding trench (GCCT). The optimization of the profile(More)
Spatial-division multiplexing in the form of few-mode fibers has captured the attention of researchers since it is an attractive approach to significantly increase the channel capacity. However, the optical components employed in such systems introduce mode-dependent loss or gain (MDL) due to manufacturing imperfections, leading to significant system(More)
Mode-division multiplexing has emerged as an imminent step to increase the capacity of long-haul transmission systems and avoid the so-called “capacity crunch”. One way to realize such systems is by means of few-mode fibers (FMFs). One of the challenges that has to be addressed in order to implement FMF-based commercial systems is the(More)
The suitability of the radio over fibre technique is assessed for next generation wireless systems employing distributed antennas. A transmission architecture is proposed for supporting multiple wideband radio channels based on subcarrier multiplexing. Three link types are investigated, each using different optical modulation devices. We conclude that the(More)
The emerging distributed antenna system (DAS) network commonly uses optical fibre as the transmission medium of radio signals sent to/from the remote antenna locations from/to a central unit. As in all access networks, the cost factor is a very critical issue and the maximization of network resource sharing is essential to optimize deployment costs.(More)
This paper presents the design of few-mode fibers (FMFs) with low differential mode delay (DMD) over the C-band, considering a refractive index profile with a graded core and a cladding trench. By optimizing the core grading exponent and the dimensioning of the trench, the lowest DMD achievable is obtained for different numbers of linearly polarized (LP)(More)
Few-mode fiber transmission systems are typically impaired by mode-dependent loss (MDL). In an MDL-impaired link, maximum-likelihood (ML) detection yields a significant advantage in system performance compared to linear equalizers, such as zero-forcing and minimum-mean square error equalizers. However, the computational effort of the ML detection increases(More)
A novel optical transmitter for millimeter-wave radio-over-fibre systems is proposed. This transmitter is designed to enable the simultaneous delivery of a subcarrier multiplexed signal at millimeter-wave and microwave frequencies, without optical filtering at the antenna site. The proposed concept was validated by simulation and experimental tests,(More)