With the recent data rate increase it is very challenging to build a fibre optic network that would enable a high data rate transmission over a long haul distance. The signal suffers large degradation over a certain distance due to distortion by the nonlinear effects of the optical fibres. In particular, transmission of high data rates over existing fibre optic systems, while keeping the cost low, avoiding an increase of the system's complexity and the usage of expensive devices, would be a very challenging task. In this paper, we address this problem by increasing the transmission distance in the fibre optic links for up to 2500km. We have used Standard Single Mode Fibre (SSMF) and Dispersion Compensation Fibre (DCF), where DCF is used as a loss compensator in Radio-Over-Fibre (RoF) systems. A mixture combination of the pre, post and symmetrical fibre compensation schemes were developed to overcome the dispersion in the fibre. We have found that in order to achieve high RF over fibre optic system performance for high data rates and long transmission, there is a requirement to upgrade the optical configuration scheme in a proportional way, by raising the length of the fibre span, compensation span and amplification. We have reported optimised RF over fibre configuration schemes that would have a great impact on reducing the cost, reducing the system's complexity and avoiding usage of expensive devices, in order to achieve high data rate transmission over existing fibre optic systems.

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In this paper, we have proposed a long-haul optical transmission system, based on a single sideband (SSB) modulation scheme. Analytical and simulation models have been developed, optimised and demonstrated for the proposed SSB system configurations. The SSB modulation scheme was proposed to overcome dispersion in the fibre. We have shown that the related link losses can be minimized by increasing the quality of the optical signal at the modulation. We have optimised the radio over fibre (RoF) configuration scheme based on Dual Parallel Dual Drive Mach Zehnder Modulator (DP-DDMZM), thereby increasing transmission length of the fibre. With the proposed SSB, by suppressing some of the harmonics and cancelling one of the sidebands, we have halved the RF power fading and interference. The developed analytical (theoretical/mathematical) model agrees very well with the simulation results using two (both) different commercial simulation tools. The optical signal is boosted while minimizing the number of repeaters. We report a SSB configuration, compensation and amplification with individual spans of 150 km, by extending the length of the link up to 3250km. The proposed system configuration exhibits high performance with less complexity and lower cost.