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Title: Microwave I.F. signal processing strategies for coherent optical communications
Author: Chaudhry, Mohammed Sabih
ISNI:       0000 0001 3530 5638
Awarding Body: University College of North Wales
Current Institution: Bangor University
Date of Award: 1993
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This thesis is concerned with the realisation of microwave phase correcting networks for implementation in high bit-rate coherent optical systems to alleviate the impairments caused by fibre chromatic dispersion. This research has focused on three main areas: further investigation of microstrip equalisation strategies, design and realisation of gallium arsenide (GaAs) monolithic microwave integrated circuit (MMIC) group delay equalisers and the system implications of equalisation. The most common and well reported models describing the dispersive characteristics of microstrip were assessed and compared to practical realisations, thereby enabling accurate modelling of the dispersive behaviour of the microstrip equaliser. The possibility of effecting a variation in the group delay characteristic of microstrip equalisers was explored by means of investigating the influences of the constituent material and physical geometry. Particular attention was given to the implications of the residual delay error resulting from the cascading of microstrip equalisers in a transparent optically amplified system. Attention is focused, for the first time, on the design and realisation of microwave pseudo-lumped-element GaAs MMIC group delay equalisers. Based on simple bridged- T networks derived from second order lattice arrangements, GaAs MMIC equalisers compensating for high bit-rate transmission over various fibre lengths have been investigated. Higher order network configurations have also been explored with reference to extending both the equalised bandwidth and fibre spans. The implications of equalised systems have been assessed, noting specifically the performance of the equalisers for linear and non-linear modulation formats. The GaAs MMIC equalisers are shown to be extremely flexible and robust to variations in the fibre spans. Additionally, the tolerance of GaAs MMIC equalisers has been investigated for slightly chirped systems with a view to implementation, ultimately in a practical system.
Supervisor: O'Reilly, John Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available