High-Speed SiGe EAMs at Cryogenic Temperatures

Electro-optic modulators capable of operating at cryogenic temperatures are of interest to a host of sensing, quantum, and supercomputing applications. Silicon photonics is compelling for its low cost and CMOS compatibility, but conventional tuning mechanisms are impacted at low temperatures. Bulk electro-absorption modulators are appealing since only the wavelength of the absorption band edge varies with temperature. Cryogenic effects on a fabricated high-speed modulator are shown, with consistent extinction ratio from 5-300K. (Abstract)