In recent years, the continuous growth of Internet traffic is boosting the demand of short-reach optical links in data centers, vastly driven by new applications such as Cloud Computing, Virtual Reality/Augmented Reality, and Internet of Things. According to a recent report from Cisco, most of the datacenter traffic stays within the mega datacenters, further increasing the demand of faster optical interconnections. To date, intensity-modulation/direct-detection (IMDD) solutions still dominate the market of short-reach optical interconnects, however experiencing lofty challenges in scaling up beyond 100Gbps per wavelength (i.e. 50Gbaud PAM-4 modulation). Coherent detection offers high spectral efficiency and receiver sensitivity, but conventional DSP-based coherent receivers have prohibitively high cost and power consumption for intra-data-center links. In this project, we will research on fundamental improvements using the proposed "DSP-lite coherent detection" techniques using analog/mixed-signal processing with an optoelectronic phase-locked loop, drastically lowering power and complexity. Furthermore, co-design and co-integration of photonic and electronic integrated circuits will be investigated to enable next-generation symbol rates beyond 100Gbaud, pushing the boundaries of optical interconnects technology.