Internet data traffic within data centre, access and metro networks is experiencing
unprecedented growth driven by many data-intensive applications. Significant
efforts have been devoted to the design and implementation of low-complexity
digital signal processing (DSP) algorithms that are suitable for these short-reach
optical links. In this thesis, a novel low-complexity frequency-domain (FD)
multiple-input multiple-output (MIMO) equaliser with momentum-based gradient
descent algorithm is proposed, capable of mitigating both static and dynamic
impairments arising from the optical fibre. The proposed frequency-domain
equaliser (FDE) also improves the robustness of the adaptive equaliser against
feedback latencies which is the main disadvantage of FD adaptive equalisers under
rapid channel variations.
The development and maturity of optical fibre communication techniques over
the past few decades have also been beneficial to many other fields, especially
coherent light detection and ranging (LiDAR) techniques. Many applications
of coherent LiDAR are also cost-sensitive, e.g., autonomous vehicles (AVs).
Therefore, in this thesis, a low-cost and low-complexity single-photodiode-based
coherent LiDAR system is investigated. The receiver sensitivity performance of this
receiver architecture is assessed through both simulations and experiments, using
two ranging waveforms known as double-sideband (DSB) amplitude-modulated
chirp signal and single-sideband (SSB) frequency-modulated continuous-wave
(FMCW) signals. Besides, the impact of laser phase noise on the ranging precision
when operating within and beyond the laser coherence length is studied. Achievable
ranging precision beyond the laser coherence length is quantified
