UC San Diego

The exponential growth in data center IP traffic entails rapidly evolving standards and optical transceiver solutions. The 200GbE and 400GbE standards were approved by the IEEE task force in 2017. Even higher speeds above 800GbE, 1.0TbE, and even 1.6TbE are forecasted to become standards a couple of years from now. To cope with the enormous

aggregated data rate demands, highly parallel pluggable optical transceiver modules based on silicon photonics technology have been proved to be the platform of choice due to their cost effectiveness and high yield, simultaneously conditioned with tremendous challenges in practical and low-power developments for the data center space.

This dissertation work explores possible solutions in three aspects. Wavelength multiplexing utilizing the nonlinear properties of the silicon waveguides is explored and experimentally demonstrated to be a valid solution to enable integrated multiple parallel wavelengths in SiP platform. Besides, wavelength and fabrication insensitive arbitrary ratio multimode interference couplers are proposed and demonstrated, enabling the design of broadband wavelength (de-)multiplexing filter circuits. The design of high-speed avalanche photodetectors with improved detection sensitivity is another exploration to lower the overall power consumption. Validated system performance improvements using avalanche photodetectors through experimental demonstrations with high-order modulation formats of both 4-level pulse amplitude modulation and coherent quadrature amplitude modulation prove the advancement in satisfying future interconnect demands.