Publications

We demonstrate a platform for phase and amplitude modulation in silicon nitride photonic integrated circuits via piezo-optomechanical coupling using tightly mechanically coupled aluminum nitride actuators. The platform, fabricated in a CMOS foundry, enables scalable active photonic integrated circuits for visible wavelengths, and the piezoelectric actuation functions without performance degradation down to cryogenic temperatures. As an example of the potential of the platform, we demonstrate a compact (∼40 µm diameter) silicon nitride ring resonator modulator operating at 780 nm with intrinsic quality factors in excess of 1.5 million, >10 dB change in extinction ratio with 2 V applied, a switching time less than 4 ns, and a switching energy of 0.5 pJ/bit. We characterize the exemplary device at room temperature and 7 K. At 7 K, the device obtains a resistance of approximately 20 teraohms, allowing it to operate with sub-picowatt electrical power dissipation. We further demonstrate a Mach-Zehnder modulator constructed in the same platform with piezoelectrically tunable phase shifting arms, with 750 ns switching time constant and 20 nW steady-state power dissipation at room temperature.

We explore fabrication-process dependencies on optical losses of AlN films and demonstrate Second Harmonic Generation through modal phase-matching in integrated AlN waveguides. A loss-dependent conversion efficiency model is developed to better design waveguides in lossy AlN media.

We demonstrate conversion of a 10GHz radio frequency signal directly to fiber optics. A Fabry-Perot cavity formed between a fiber tip and an AlN-film acoustic resonator electrode enables resonantly enhanced phase modulation of back-reflected light.

Abstract not provided.