Felipe Rudge Barbosa

Optical amplitude multiplexing through four-wave mixing in optical fibers

We propose a new optical amplitude multiplexing technique that consists of merging two wavelength multiplexed on-off keying (OOK) signals into a single quaternary amplitude shift keying signal. This technique is based on four-wave mixing in a single-mode optical fiber and requires power offset from the OOK signals. Simulation results indicate that the multiplexing may be performed between signals of the same or different bit rates. As a consequence, the proposed technique may be used not only for increasing spectral efficiency but also for optical labeling.

Quaternary optical packets generated by fiber four-wave mixing

Recent work suggests that fiber four-wave mixing may be used to merge two wavelength multiplexed binary channels into a single quaternary signal. In this letter, we investigate the application of this technique to the optical packets generation considering that a 10-Gb/s payload is optically multiplexed to a 2.5-Gb/s label. Computer simulations are used to analyze the propagation of the generated quaternary optical packet in the dominance of amplified spontaneous emission noise. Results suggest that the optical packet may be propagated through metropolitan area networks length scales and that an average power around 0 dBm should be used to minimize the packet bit-error rate.

The effects of polarization mode dispersion on 2D wavelength-hopping time spreading code routed networks

In this study, we investigate the effects of multiple access interference (MAI) and polarization mode dispersion (PMD) in 2D wavelength-hopping time spreading optical code paths. The main results show the MAI effects and PMD constraint at the outage probability. The contribution of these sources of interference is analysed to choose the better design of code parameters in order to increase the performance of networks based on optical code paths. These results could be applied to determine the parameters design in code/wavelength routed networks.

Analysis of electronic buffers in optical packet/burst switched mesh networks

We present in this paper the study of electronic buffering in an innovative architecture for optical packet/burst switched network (OPSN). This architecture comprises optical bufferless nodes with electronic packet queuing out of the optical layer, deflection routing to perform contention resolution and fully connected mesh topologies under uniform traffic distribution. We demonstrate, by means of simulation, that the studied architecture has a great improvement in performance when we introduce such electronic buffers, which are more efficient when used with the optimized mesh topologies.

Design of multi-rate optical code paths considering polarisation mode dispersion limitations

The authors propose an original design based on multi-rate optical code paths (OCPs) for transport in advanced wavelength-division multiplexing/optical code division multiplexing (WDM/OCDM) networks. The authors utilise multi-length optical orthogonal codes (OOC) to obtain multi-rate OCPs. The performance of the proposed scheme is analysed and the impact of multiple access interference (MAI) and polarisation mode dispersion (PMD) over these OCPs is evaluated. Results show that not only multi-rate operation can be achieved but also MAI effects can be reduced, while mitigating PMD effects.

Evaluation of throughput and protection in optically switched metropolitan network architectures

In this study, we investigate the performance of optical packet/burst switched (OPS/OBS) architectures connected as mesh and as ring topologies for future optical metropolitan networks. Network throughput and protection to link failure under uniform traffic distribution for all nodes are investigated to evaluate the sensitivity of OPS/OBSN performance. Our data are based on analytic results and computer simulations that include a comparison between various mesh and ring topologies. We also consider detailed traffic distributions over the network links and the impact caused by failure of more or less loaded links, thus providing a method to select links that require protection, which can be very useful in network planning.

Performance analysis of optical code switching router

In this work we study and evaluate the performance of an optical code switching router (OCSR), intended to be utilised in hybrid wavelength-division multiplexing/optical code-division multiplexing (WDM/OCDM) networks. This OCSR can transport and route efficiently user data over optical code paths without departing from the optical domain. Limitations of the proposed OCSR are investigated and its superior performance demonstrated based on non-coherent prime codes. Our results indicate that our solution is useful in showing the effects of the optimum threshold level on the OCSR performance. We propose a continuous adjustment of the optimum threshold level based on the measurement of the mean optical power before the decoder. The influence of various parameters of the optical codes on the OCSR performance are also considered and evaluated. Copyright

Effects of multiple access interference and PMD on optical code lightpaths

In this work we investigate the effects of multiple access interference (MAI) and polarization mode dispersion (PMD) in optical code division multiplexing (OCDM) lightpaths. These paths are determined by the data encoding with non-coherent optical orthogonal codes (OOC), using a sequence inversion keying (SIK) optical correlator system. Our results show the impact of MAI effects and PMD constraint on the packet error rate, which depends on OOC parameters like weight and length. These parameters in turn depend on MAI and PMD effects. The results obtained can be used as input parameters for the design of OOC in virtual code/ wavelength path (VOCP/ VWP) routed networks.

Dynamic traffic analysis of metro-access optical packet switching networks having mesh topologies

We have investigated the performance of various optical packet switched network (OPSN) architectures comprising optical bufferless nodes and fully connected mesh topologies, under uniform traffic distribution, i.e., all nodes generate the same traffic. We demonstrate that increasing the number of nodes in OSPNs does not necessarily increase performance, or even capacity. By establishing an efficiency parameter based on average number of hops and effective network capacity, decision tables and graphs can be generated and utilized in network planning. Moreover, regular and quasi- regular optimized topologies lead to lower latency, higher throughput, and lightpaths with significantly better traffic distribution. The optical nodes have simple configuration and are totally compatible with WDM networks.

Contribution to future metropolitan access network planning considering link failures in photonic switched networks

Photonic switching for traffic optimization in Metropolitan Access Optical Networks using technologies of optical packet/burst switching (OPS/OBS) seems to be a future-proof solution considering high capacity and the highly variable traffic in these networks. Looking for this future, we propose a study based on the analyze of survivability of traffic unconsidering protection mechanism but considering mesh and ring efficient topologies with node architecture to OPS. The results are obtained through computer modeling and simulation. The main parameters analyzed are as follows: capacity, average number of hops, packet loss fraction, and link utilization for each topology. These parameters are adopted to evaluate the performance of each topology considering failures. Minimum electronic buffering is included at node ingress (client side) to avoid packet loss in the access to the optical layer: high throughput and low latency. It is also observed that optical buffering is not necessary for adequate network performance.