Digital signal processing (DSP) is key for high-speed intensity-modulation direct detection (IM/DD) data center connections. In this Master thesis, the challenges in designing high-speed data center interconnects (DCIs), such as limited bandwidth and chromatic dispersion, are explained, important digital algorithms for dealing with this challenges are discussed and the implementation of these algorithms is verified with five cutting-edge optical transmission experiments. The importance and success of this work is emphasized by three accepted paper submissions to an international conference