Enabling High-Bandwidth Coherent Modulation Through Scalable Lithium Niobate Resonant Devices

TL;DR

This paper introduces a compact, high-bandwidth coherent modulator on a lithium niobate platform, achieving 29 GHz bandwidth and supporting advanced modulation formats for scalable optical communication.

Contribution

It presents a novel resonant modulator design using Mach-Zehnder Interferometers with Gires-Tournois etalons, eliminating traveling-wave electrodes and enhancing scalability and performance.

Findings

Achieved 29 GHz modulation bandwidth.

Demonstrated low optical loss and high scalability.

Supported advanced modulation formats like QAM.

Abstract

We present a compact, resonant-based coherent modulator on a thin-film lithium niobate (TFLN) platform, addressing the growing demand for high-speed, energy-efficient modulators in modern telecommunications. The design incorporates Mach-Zehnder Interferometers (MZIs) with a Gires-Tournois etalon in each arm with a modulation region of only ~80 micrometers, eliminating the need for traveling-wave electrodes and enabling compatibility with wavelength-division multiplexing (WDM). Experimental results demonstrate a modulation bandwidth of 29 GHz, while ensuring low optical loss and high scalability. Our architecture supports in-phase and out-of-phase modulation, enabling differential control of amplitude and phase for advanced modulation formats such as quadrature amplitude modulation (QAM). Compared to previous designs, our approach enhances throughput, modulation density, and scalability, making it ideal for applications in coherent communications and optical computing. By combining the advantages of the TFLN platform with innovative resonator engineering, this work advances the development of compact, high-performance modulators for high-density on-chip communication networks.