High-speed electro-optic modulator based on silicon nitride loaded lithium niobate on an insulator platform

TLDR

Electro‑optic modulators convert electrical signals to optical signals and are essential for modern optical communication, and lithium‑niobate‑on‑insulator technology has become a competitive platform for high‑performance integrated modulators. This work designs and experimentally demonstrates a Mach‑Zehnder interferometer‑based modulator on a silicon nitride‑loaded LNOI platform. The design exploits the strong EO effect of LiNbO3 while avoiding direct etching of the thin film by loading it onto silicon nitride. The fabricated modulator achieves a half‑wave voltage‑length product of 2.24 V·cm, an extinction ratio of ~20 dB, a 3 dB bandwidth of ~30 GHz, and supports on‑off key data rates up to 80 Gbps.

Abstract

Electro-optic (EO) modulators, which convert signals from the electrical to optical domain plays a key role in modern optical communication systems. Lithium niobate on insulator (LNOI) technology has emerged as a competitive solution to realize high-performance integrated EO modulators. In this Letter, we design and experimentally demonstrate a Mach-Zehnder interferometer-based modulator on a silicon nitride loaded LNOI platform, which not only takes full advantage of the excellent EO effect of LiNbO3, but also avoids the direct etching of LiNbO3 thin film. The measured half-wave voltage length product of the fabricated modulator is 2.24 V·cm, and the extinction ratio is ∼20dB. Moreover, the 3 dB EO bandwidth is ∼30GHz, while the modulated data rate for on-off key signals can reach up to 80 Gbps.