Low Driving Voltage and Low Optical Loss Electro-Optic Modulators Based on Lead Zirconate Titanate Thin Film on Silicon Substrate

Heterogeneous integration of electro-optic (EO) crystal thin film on insulator has become an attractive platform to achieve high-performance and compact modulators. While there has been some impressive research on the development of such modulators, a critical consideration is the relatively complex heterogeneous-integrating process. In this work, we demonstrate EO modulators based on lead zirconate titanate (PZT) crystal thin film on SiO ₂ /Si substrate, where the PZT is epitaxially-grown via the straightforward chemical solution deposition method. The presented device exhibits a voltage–length product V_πL of 1.4 V·cm and a propagation loss of 1.8 dB/cm at the wavelength of 1550 nm. The measured 3-dB bandwidth of a 5 mm-long device is 12 GHz, which can be improved by further optimizing the travelling-wave electrodes. The proposed technique should enable low-cost and mass-production of power-efficient modulators and to promote the development of photonic integration.