Ultra-Compact On-chip Electro-Optic Waveguide Ring Resonators Based on Asymmetric Au-(Pb, La)(Zr, Ti)O3-Au Structure

Abstract

Waveguide ring resonators (WRRs) operating at a telecom window of 1.4∼1.6 μm based on asymmetric Au-(Pb, La)(Zr, Ti)O 3 -Au structure is proposed and investigated. Electro-optical control of such WRRs is conducted by introducing epitaxial (Pb, La)(Zr, Ti)O 3 (PLZT) thin films as the core layer deposited between the upper and lower gold slabs with different widths. The long-term reliability, large electrooptic (EO) coefficients, and spontaneous polarization properties of PLZT thin films have ensured high performance of our WRRs. It has been demonstrated that the footprint of WRR can be fabricated less than 20 μm 2 with the radius of ring resonator around 1 μm through combining PLZT thin films with surface plasmons (SPs). Furthermore, the large extinction ratio (∼43 dB), as well as comparatively low insertion loss (<10.5 dB), and moderate modulation sensitivity (0.8 nm/V) can be achieved with proposed WRRs in the wavelength range of 1.4∼1.6 μm. Besides, the strong mode confinement capacity of such asymmetric metal-insulator-metal (MIM) structure can support high bending waveguides, paving the way for the fabrication of more compact electro-optic WRRs with nanometer-scale radius that can work in the other wavelength ranges.