Strong piezoelectric + electro-optic ferroelectric for Si-integrated modulators
Physics / mechanism
PZT is a perovskite ferroelectric oxide with strong piezoelectricity (~600 pC/N) and Pockels electro-optic coefficient (~100-200 pm/V — comparable to BTO and ~5× LiNbO₃). Mature in piezo MEMS (sensors, actuators, ultrasound) and ferroelectric memory (FRAM, decades-mature for niche markets).
The photonic angle: PZT thin films on silicon (PZT-on-SOI, PZT-on-SiN) integrate strong EO modulation with the silicon photonic ecosystem. Sol-gel and PLD deposition routes are well-developed but require post-processing crystallisation that complicates CMOS-fab integration.
Competitive landscape
EpiPhotonics (US, IBM Zurich derivative) is the lead commercialisation effort for PZT-on-SOI modulators. IBM Zurich, Princeton, and several European groups have published PZT-on-Si EO demonstrators. Lead-content regulatory pressure (RoHS) is a real constraint that limits some markets.
Frontier (open questions)
See frontmatter frontier: block.