CMOS-compatible, piezo-optomechanically tunable photonics for visible wavelengths and cryogenic temperatures

Abstract

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 2x10 13 Ohms, 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.

Nanobenders as efficient piezoelectric actuators for widely tunable nanophotonics at CMOS-level voltages

“…As illustrated above, the diagonal elements of d, d 11 (22,33) give rise to tens of picometers of displacement at a potential of around one volt. A much larger displacement can be generated with transverse d (d 12 (13,23) ) components (Fig. 1a).…”

“…In this work, we show how manifestation of the piezoelectric effect in a nanostructure can be used to realize transducers with capabilities beyond the range/footprint/speed/sensitivity trade-off present in electrostatic devices. In the context of piezo-photonic integration, our work follows several efforts [20][21][22][23] to implement piezo-optomechanically tunable cavities and waveguides which have resulted, for example, in demonstrations of cavity wavelength tuning coefficients ranging from 0.1 to 30 pm V −1 [21][22][23] .…”

High-speed programmable photonic circuits in a cryogenically compatible, visible–near-infrared 200 mm CMOS architecture

“…Silicon electric-field induced 24 modulators are promising but have not been realized at scale and restrict operating wavelength power. χ (2) A recently introduced alternative relies on piezo-optomechanical actuation of SiN waveguides, [25][26][27][28] which in the case of 25 has enabled narrow-band operation up to 250 MHz with SiN waveguides for visible-NIR operation and high optical power handling. Finally, the energy requirement (iii) is incompatible with any thermal modulation schemes, which dissipate an average of >800 mW for doped SiO2, 21 >20 mW per modulator for SOI 29 , and >40 mW per modulator for SiN.…”

“…1d, e, through co-design and development of photonics, electromechanics, electrical and mechanical control systems, and driver software. We combine the best attributes of different devices in our previous work 25 into a proof-of-principle PMMI architecture capable of 20 ns reconfiguration time, on-chip dissipation per modulator below 200 µW when switching on average every 1 µs and 6 nW power to hold, operation at 700 -780 nm with optical transmission up to 1550 nm, and improved power efficiency at 5 K.…”

Quantum information processing in large-scale photonic networks

“…This problem can be circumvented by adopting other switching methods. An example are stress-optical modulators using PZT [287,288] or optomechanics [289,290]. Other improvements to the integrated processor can be the integration of single-photon sources and detectors [291,292].…”