SATNAC 2008 Conference Papers

Optical, Transport & Core Networks

Title:                An Emission and Discard Priority Scheme for OBS Networks

 

Authors:            Pascal Acquaah (University of Cape Town), Anthony Chan (University of Cape Town)

 

Abstract:           A key issue in Optical Burst Switched (OBS) networks is resolving burst contention in an efficient and cost-effective manner. Although deflection routing has been identified as a cost-effective solution, its viability has been questioned. We propose an Emission and Discard Priority (EDP) scheme to alleviate the shortcomings of deflection routing by reducing late packet arrivals and hence improving network goodput. Simulation results show that the deflection with EDP scheme has a lower proportion of late packet arrivals than a basic deflection routing scheme. Furthermore, the deflection with EDP scheme has higher goodput when the normalized load L >= 0.7 and has higher efficiency than the basic deflection routing scheme in terms of goodput per deflection.

 

 

Title:                Optical Polarization Mode Dispersion Compensator for 40 Gbit/s NRZ and RZ systems

 

Authors:            Roberto Cigliutti (Pirelli Labs, Milano, Italy), Andrea Galtarossa (University of Padova, Italy), Massimo Giltrelli (Pirelli Labs, Milano, Italy), Danile Grosso (University of Padova, Italy), Andrew Leitch (Nelson Mandela Metropolitan University), Luca Palmieri (University of Padova, Italy), Stefano Santoni (Pirelli Labs, Milano, Italy), Luca Schenato (University of Padova, Italy), David Waswa (Nelson Mandela Metropolitan University)

 

Abstract:           Polarization Mode Dispersion (PMD) represents a major impairment for high bit rate systems resulting in pulse broadening and distortion and leading to system performance degradation if it is not handled properly. PMD is particularly difficult to assess because unlike the chromatic dispersion, it varies stochastically in time. Basically, there are two different approaches to mitigate PMD effects: by deploying ultra-low PMD fibers or by using PMD compensators. While the former solution represents an option for new installations, the latter is the preferable solution for in-service systems. In this paper we present an optical PMD compensator able to compensate up to 25 ps of differential group delay in NRZ and RZ 40 Gbit/s systems.

 

 

Title:                The Impact of a High Birefringence Section in an Optical Network System through Emulation

 

Authors:            Vitalis Musara (Nelson Mandela Metropolitan University), Lorinda Wu (Nelson Mandela Metropolitan University), Gaoboelwe Pelaelo (Nelson Mandela Metropolitan University), Andrew Leitch (Nelson Mandela Metropolitan University)

 

Abstract:           Polarization mode dispersion (PMD) contributions by each birefringent fibre section on an optical network link can be best analyzed through PMD emulation. The authors design a sub-emulator from coupling sections of polarization maintaining fibres (PMFs) to mimic the DGD behaviour in a deployed fibre. To show the impact of a high birefringent (HiBi) fibre in an optic network a 23 m single PMF section is coupled to the sub-emulator via a polarization controller (PC). Results show that the RMS-DGD of the emulator is always ~ 31 ps which is close to that given by the HiBi section. Simultaneous adjustments in the maximum and minimum values of the DGD statistics are also achieved.  We go further to show that the presence of a HiBi section in an optical link can shift the DGD statistics away from the Maxwellian distribution.

 

 

Title:                Impact of Polarization Dependent Loss in the Presence of Polarization Mode Dispersion on Optical Network

 

Authors:            Gaoboelwe Pelaelo (Nelson Mandela Metropolitan University), Lorinda Wu (Nelson Mandela Metropolitan University), Vitalis Musara (Nelson Mandela Metropolitan University), Andrew Leitch (Nelson Mandela Metropolitan University)

 

Abstract:           We investigate the behaviour and impact of polarization dependent loss (PDL) in the presence of polarization mode dispersion (PMD) in an optical network.  PDL and PMD degrade the optical transmitted signal and therefore limit the system performance. Besides measuring PMD by the Jones matrix eigenanalysis (JME) method, we also determined it from the fast Fourier transform (FFT) of the PDL data and the results compared. Long term PDL measurements are conducted which show that PDL changes significantly with wavelength and varies only slightly with time.


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