Polysilicon micro-heaters for resonance tuning in CMOS photonics

A new, to the best of our knowledge, device platform for tuning the resonance wavelength of integrated photonic resonators based on polysilicon-based micro-heaters for complementary metal-oxide semiconductor (CMOS)-foundry-based active Si photonics is demonstrated. The miniaturized micro-heater can be placed directly on the active Si layer, with a pedestal providing the optical and electrical isolation needed for the implementation of ultrafast active photonic devices such as modulators. The demonstrated devices do not require any additional modifications to the standard CMOS foundry processes. Experiments demonstrate a tuning efficiency of 0.25 nm/mW (or 42 GHz/mW) for a 5-µm-radius microdisk resonator with a loaded quality factor (Q) > 35,000. This polysilicon-based heater demonstrates a tunability of 42 GHz/mW with an average switching time of 60 µs. The proposed compact heater architecture enables it to be kept near to the optical mode, thereby providing efficient and high-speed wavelength tuning for resonant devices.