Hon Ki Tsang was born in Hong Kong. He entered the then emerging field of silicon photonics in 2000. Those early silicon photonic products enabled dynamic balancing of optical power levels during the reconfiguration of Wavelength Division Multiplexed (WDM) in commercial telecommunication systems. From its small beginnings attracting interest from only a handful of groups 25 years ago, silicon photonics has grown to be an major new platform for research (watch Tsang’s interview by OSA) to become a mainstream technology for high-speed energy-efficient data interconnects in data centers, with large volume of Si photonics transceivers underpinning the growth of the internet and the development of Artificial Intelligence. Silicon photonics today remains a promising area for academic research because there remains many important potential future applications that are relatively unexplored for advancing the performance of microelectronic systems beyond what could be achieve by using purely electrical circuits. The use of photons in photonic integrated circuits not only offers significant improvements in energy-efficiency for high-capacity data interconnects in high performance computers, but photons are naturally more useful than electrons for sensing the environment (humans relay on light to see!). The processing of light signals in photonic integrated circuits offers advanced capability in photonic systems on chip for future applications in integrated gas sensors, integrated biosensors for heath monitoring, advanced three-dimensional imaging systems, and integrated quantum photonic devices for quantum computing, quantum metrology and quantum communications. Tsang’s research contributions to the field of silicon photonics include developing a basic understanding of the nonlinear properties of silicon optical waveguides: he carried the first experimental measurements of the Kerr nonlinearity in silicon waveguides, the first studies of two photon absorption and associated free carrier absorption that forms the basis of the now widely accepted model of two photon absorption and free carrier absorption in silicon waveguides. With this understanding he was able to realize the first high net-gain waveguide silicon Raman amplifier in 2004. These papers are important because the tiny cross-sectional areas of silicon waveguides enable nonlinear optical effects such as two photon absorption or self-phase modulation to manifest at optical powers as low as a few milliwatts. Tsang’s research group’s most recent research contributions include the first multimode waveguide grating couplers for selective-launch of different modes in multimode fibers, advances in waveguide grating couplers that enabled sub-decibel coupling loss using standard foundry photolithography and fabrication process, and advances in the state-of-the-art for Si modulators to demonstrate class leading modulator data rates >300Gb/s.