Silicon (Si) photonics is well-positioned to provide high-speed and low-cost optical interconnects. The extraction of data from cryogenically cooled integrated circuits (ICs) has become of great interest for low-power data readout. Utilizing wavelength division multiplexing (WDM), a high capacity optical interconnect can be realized using remoted Si photonic based ring resonator modulators (RRMs). Results include operation up to 20 Gbps and BER < 1E-12 using a 2 Vpp signal, consuming < 100 fJ/bit in the cold environment. Lastly, Si photonic RRM device and interconnect optimizations for operation at temperatures ≤ 77 K will be presented.
Parasitics such as wirebond inductances and bond pad capacitances that result from hybrid opto-electronic integration pose a challenge towards achieving data rates beyond 50 Gb/s. The effect of bond pad capacitance on the receiver transimpedance limit is shown, which demonstrates the significant advantage of monolithic versus hybrid integration. An analysis of three receiver topologies is presented. These all employ the same Cherry-Hooper voltage amplifier for the core electronics. A comparison across several design metrics of the three Transimpedance amplifier (TIA) variants is then provided. The TIAs are implemented monolithically in the IHP 250-nm SiGe BiCMOS EPIC process (fT = 190 GHz). Measurement results are then presented for 50 Gb/s OOK. PAM4 simulations are also shown.