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Physics

The Optical Fibre Research Unit was established in the Department of Physics at NMMU (formerly University of Port Elizabeth) in 2001. The main goal of the Research Unit is to study the optical characteristics of optical fibres and cables in high speed telecommunication networks, with emphasis placed on the assessment of polarization mode dispersion (PMD). PMD is the phenomenon whereby the two polarization states of a light wave are transmitted at different speeds through the fibre, resulting in a measured dispersion of the signal. It is attributed to the intrinsic birefringence in the fibre, as well as birefringence caused by external stresses that may be present (due to, for example, thermal fluctuations). PMD is currently one of the major factors that limit high data rate networks operating beyond 10 Gbps.

Projects range from fundamental studies of the nature of PMD and its measurement, the compensation and emulation of PMD, to studies on the effects of different cabling processes and environmental factors on the PMD characteristics of optical fibres. An assessment is also currently underway of the PMD characteristics of the existing optical cable network in South Africa. Additional projects and areas of interest include other polarization effects in optical fibres: the interaction between second-order PMD and nonlinear effects; and the interaction between PMD and polarization dependent loss (PDL).

Results are presented each year at the South African Institute of Physics (SAIP) conference, as well as the South African Telecommunication Networks and Applications Conference (SATNAC) hosted by Telkom. The Optical Fibre Research Unit has also has numerous internationally recognised journal and conference proceeding outputs.

An important component of the project will involve the training of students at various levels of expertise, to meet the increasing demand in South Africa, other parts of Africa and further afield, for graduates with these skills. We are also linked to the African Laser Centre, through whom senior students and researchers from other parts of Africa may receive financial support for research and training in our Unit. Strong links with industry provide students with opportunities to gain field experience, as well as perform laboratory measurements to investigate phenomena that have direct bearing on the telecommunications industry. We also have formal collaborations with theDeparment of Information Engineering,University of Padova, Italy and the Department of Photonics Engineering, Technical University of Denmark, Denmark.

For details on each of our students' projects, click on their names below:

Name Level
Romeo Gamatham PhD
Enoch Rotich PhD
Hamed Kourouma PhD
Valentin Chabata PhD
Shukree Wassin Msc
   

Generous industrial funding has allowed the acquisition of state-of-the-art equipment that makes our Laboratory the best equipped in South Africa for this type of research. Available equipment includes the following (see photos):

  • Exfo femtosecond PMD measurement system (Generalized Poincaré Sphere Analysis technique) 
  • Exfo Ginty interferometer-based PMD system
  • Santec PMD measurement system (Cross-correlation interferometer technique)
  • Exfo PDL and return loss measurement system
  • Sumitomo fusion splicer
  • Exfo OTDR system
  • Agilent OSA system
  • Adaptif high-speed polarimeters (two)
  • Adaptif high-speed polarization scramblers/controllers (two)
  • Agilent tuneable laser source
  • Multiple ASE and broadband sources
  • Thorlabs DWDM laser sources
  • Amonics high power Er-doped fibre amplifier
  • Variable optical delay lines, tuneable optical filters and variable attenuators
  • 10Gb/s bit error rate test system with NRZ/RZ/DPSK modulator
  • VPI and Matlab are also used extensively for modelling and simulation purposes