Advances in Low Energy SiGe APD Optical Link

Wavelength division multiplexing (WDM) combined with four-level pulse amplitude modulation (PAM-4) can double the data rate at the same baud rate and allow for realization of high bandwidth and high density interconnects. Due to this reason, PAM4 has becoming a mainstream modulation scheme for the standardization of 400 Gb/s Ethernet (400bE). High-sensitivity receivers with internal gain can relieve the link budget challenge in operations of PAM4 and wavelength division multiplexing (WDM) and achieve high energy efficiency. Here we demonstrates a 60 Gb/s PAM4 waveguide Si-Ge avalanche photodiode (APD) with low breakdown voltage of −10 V. A low energy WDM SiGe APD optical link architecture involves Si hybrid comb lasers, Si microring modulators and SiGe APDs is also presented.