Electro-optically modulated polarization mode conversion in lithium niobate ridge waveguides

TL;DR

This paper demonstrates an efficient, actively switchable polarization mode converter in lithium niobate ridge waveguides, leveraging electro-optic modulation to simplify fabrication and enhance integrated photonic device capabilities.

Contribution

It introduces a novel electro-optic polarization mode converter in LNOI ridge waveguides that does not require tapering or poling, simplifying fabrication and enabling active switching.

Findings

Achieved 97% polarization mode conversion efficiency.

Enabled active switching with external electric fields.

Simplified fabrication process without tapering or poling.

Abstract

Lithium niobate on insulator (LNOI) waveguides, as an emerging technology, have proven to offer a promising platform for integrated optics, due to their strong optical confinement comparable to silicon on insulator (SOI) waveguides, while possessing the versatile properties of lithium niobate, such as high electro-optic coefficients. In this paper, we show that mode hybridization, a phenomenon widely found in vertically asymmetric waveguides, can be efficiently modulated in an LNOI ridge waveguide by electro-optic effect, leading to a polarization mode converter with 97% efficiency. Moreover, the proposed device does not require tapering or periodic poling, thereby greatly simplifying the fabrication process. It can also be actively switched by external fields. Such a platform facilitates technological progress of photonic circuits and sensors.