Surface acoustic microwave photonic filters on etchless lithium niobate integrated platform

TL;DR

This paper demonstrates high-performance microwave photonic filters on an etchless lithium niobate platform using bound states in the continuum, enabling ultralow-loss guidance and high-efficiency modulation for advanced wireless communication.

Contribution

It introduces a novel etchless lithium niobate platform employing bound states in the continuum for low-loss waveguiding and integrated microwave photonic filters with high quality factors.

Findings

Achieved acoustic time delays from 21 to 106 ns.

Realized passbands with bandwidths as narrow as 0.89 MHz.

Demonstrated operation at gigahertz frequencies.

Abstract

Lithium niobate on insulator emerges as a promising platform for integrated microwave photonics because of its capability of ultralow-loss guidance and high-efficiency modulation of light. Chip-level integration of microwave filters is important for signal processing in the 5G/6G wireless communication. Here, we employed the principle of bound states in the continuum for low-loss waveguiding on an etchless lithium niobate integrated platform, and realized high-performance microwave photonic filters thereon. These microwave photonic filters consist of a high-quality photonic microcavity modulated by piezoelectrically excited surface acoustic waves. Acoustic time delays from 21 to 106 ns and passbands with bandwidth as narrow as 0.89 MHz were achieved in the fabricated filters operating at gigahertz frequencies. Our demonstration may open up new applications on the lithium niobate integrated platform, such as optical communication, signal processing, and beam steering.