PORT: A piezoelectric optical resonance tuner

Abstract

This abstract presents an aluminum nitride (AlN) piezoelectric actuator for tuning optical resonance modes of silicon nitride photonic resonators. The AlN actuator is fabricated on top of a thick silicon dioxide cladding that encapsulates the nitride resonator and waveguide. The PORT is defined by undercutting the cladding layer with a lateral silicon etch. It tunes the optical wavelength by 20pm on applying 60V to the top electrode with a 0.5nA current draw. The thick oxide cladding preserves the resonator's loaded quality factor Q optical of 64,000 across the entire tuning range. The first bending mode is at 1.1MHz enabling a tuning speed of <1µs.

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

“…1(c), excess oxide is etched away from the top of the platform to increase compliance and the ring is positioned close to the edge of the actuation platform to maximize waveguide strain. The responsivity is also significantly higher than similar devices previously demonstrated in aluminum nitride [22][23][24], which used an 800 nm thick and 1.8µm wide silicon nitride waveguide with 2 μm oxide separating the ring from the actuator. The ring modulator design, shown in Figs.…”

“…There have been attempts to use aluminum nitride to piezoelectrically strain optical waveguides to achieve modulation. This form of modulation allows a larger range of waveguide materials, with previous demonstrations of AlN piezoelectrically modulating AlN waveguides directly [15][16][17][18][19][20][21], and silicon nitride waveguides [22][23][24]. Demonstrations of directly piezoelectrically modulating AlN waveguides suffer from the same high losses at near-visible and shorter wavelengths as mentioned above.…”

MEMS for Photonic Integrated Circuits

“…8d) [54]- [56]. Piezoelectric actuation was utilized to tune the optical path length in SiN resonators [57], [58]. Additionally, strain has been used to tune the effective index of waveguides ( Fig.…”

“…Piezoelectric-based phase shifting, in contrast, does not require deconfined waveguides nor transitions, and as a result, insertion loss can be much lower. The dominant contribution becomes the propagation losses, and even with the largest reported structures, the associated IL remains low [57], [58], [60], [61].…”

“…Another option for better linearity is to change the propagation length instead, removing the exponential dependence of a gap change. Linear phase shifts can also be achieved using piezoelectrics [58], [60], [61], and quadratic with comb-drive actuators [54], [55].…”