Year: 2026
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide Integrated photonics at submicrometer wavelengths holds the potential to enable scalable microsystems for quantum technologies, metrology, biophotonics, sensing, and displays, but on-chip modulation in this range remains challenging due to the limited availability of integration-ready materials that combine optical transparency with fast electro-optical (EO) modulation. Thin-film lithium niobate (TFLN) offers strong EO properties and a broad transparency window, and recent advances are rapidly expanding the functionality and performance of integrated TFLN platforms. At sub-μm wavelengths, however, the EO response is suppressed at low frequencies by rapid dielectric relaxation, hindering stable EO biasing and bias-sensitive operation. Here, we report sub-μm-wavelength TFLN Mach–Zehnder modulators (MZMs) that decouple bias control from radio frequency EO modulation by integrating thermo-optic (TO) phase shifters: the TO section provides stable bias tuning, while the EO section is reserved for high-frequency operation. Devices targeting wavelength bands from blue to 940 nm are fabricated in a single wafer-scale TFLN process, providing a foundry-compatible approach for bias-stable modulation across this spectral range. A blue-green MZM achieves an EO V π L of 0.91 V·cm at 488 nm, a TO P π of 40.4 mW at the same wavelength, and an EO bandwidth of >26.5 GHz at 461 nm, while a near-infrared MZM achieves an EO V π L of 2.81 V·cm, a TO P π of 150.3 mW, and an EO bandwidth of >26.5 GHz at 940 nm. We characterize the dielectric-relaxation time constants of the EO sections across all three designs and find values in the range of 0.9–6 μs. We further demonstrate bias stability exceeding 1 h at 461 nm and high-extinction-ratio pulse generation sustained for over 1.5 h at 875 nm, highlighting thermal biasing as a practical and scalable solution for bias-stable, high-speed TFLN modulators across the visible and submicrometer near-infrared spectrum.
Source: ACS Photonics
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Funder: Max-Planck-Gesellschaft
OpenAlex ID: W7166198461