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Title: Design of next generation optical transmission systems
Author: Chin, H. M.
ISNI:       0000 0004 8497 8179
Awarding Body: UCL (University College London)
Current Institution: University College London (University of London)
Date of Award: 2016
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In this thesis investigations were performed into the design of optical channels for coherent optical fibre transmission systems for future optical networks. Firstly, an overview of traditional optical networks design and next generation concepts under research for the next generation of optical networks is given. The coherent receiver was then investigated experimentally as an investigative tool to provide information for channel provisioning, by fast C-band spectral analysis and estimating neighbouring channel power. An algorithm incorporated these two abilities and successfully provisioned a polarization multiplexed quadrature phase shift keying (PM-QPSK) signal in a populated system. Probabilistic versus traditional deterministic design methodology was examined to determine its advantages by perturbing intra-link optical power. Experimental results showed that due to the non-linearity of the transmission medium, a more ideal provisioning point could be determined. A three parameter model was proposed to fit the behaviour of optical power and was shown to fit the behaviour of a single channel system. A wavelength division multiplexed (WDM) system was then used to validate the model's prediction ability with high accuracy. In light of the potential increased polarization dependent loss (PDL) of next generation optical networks, the influence of up to 6 dB distributed link PDL is investigated for a 35 Gbaud coherent WDM system over 120,000 discrete instantiations for PM-QPSK and polarization multiplexed 16-level quadrature amplitude modulation (PM-16QAM) using commercial transceivers. Less than a 1 dB penalty to SNR was observed for a 6 dB range of optical launch powers. This thesis concludes with a method for estimating the performance margin for a PM-16QAM system using a pre-existing PM-QPSK system with the intended use for adaptive change of modulation format on the fly. The largest error in estimation of this margin is less than 0.4 dB over a range of 4 dB optical launch power.
Supervisor: Savory, S. J. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available