This PhD research project will be focused on linearization and phase control of novel Microwave Photonic Link (MPL) system. The Intermodulation Distortions (IMDs), as well as the harmonic distortions will be eliminated. A mathematical model including simulations will be implemented for the proposed configuration. Dual-parallel Mach-Zehnder modulator (DMZM) is most commonly used modulator for elimination or suppression of IMDs and possibly for dynamic increase range which requires complex radio-frequency arrangement and linearization. Whereas Third Intermodulation Distortion (IMD3) is the most rigorous in signal linearization, down to being very close to transmitted signal and limiting free dynamic range. Conversely, when signals are very close to each other, the Second Intermodulation Distortions (IMD2) along Second Order Harmonics (SOH) will experience severe distortions. Linearization techniques will be investigated to supressing IMDs. The RF linearization for this configuration will be tested by introducing additional multiple RF signals, as well as phase control in the subsystem branches. This project includes mathematical modeling and control of short and long term phase instabilities of analogue RF over fibre links as applied to direction finding and steerable phased arrays, phase distortion aspects analysis and potentially exploring the SBS filtering techniques. During this studentship we aim to develop and demonstrated a high linear analogue photonic link where all IMDs and SOH will be eliminated, by deploying unique system architecture. It will be demonstrated that IMDs and SOH distortion products can be completely eliminated, which is a challenging task to achieve due to the fact that if signals are very close to each other, it will be very difficult to filter SOH by using various filtering techniques. We have demonstrated that the system SFDR is only limited by TOH distortions which are far apart from fundamental signal and can easily be filter by using low electronic filters.
The proposed MPL system configuration exhibits significant performance and it will have great impact on aerospace, radar and satellite-to-ground downlink communication system applications. This research studentship will be supported by PPM ltd. (Regular meetings will be held with PPM to report progress to be agreed, with the potential opportunity to have a short placement of the student at the PPM facility, to be agreed as appropriate.)
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