Folded electro-optical modulators operating at CMOS voltage level in a thin-film lithium niobate foundry process

Area of Science:

• Photonics
• Materials Science
• Electrical Engineering

Background:

• Integrated electro-optical modulators are crucial for high-density, low-power photonic applications.
• Thin-film lithium niobate (TFLN) offers excellent low-voltage and high-bandwidth performance.
• Achieving low half-wave voltage (<1 V) typically requires long device structures, hindering miniaturization.

Purpose of the Study:

• To develop compact folded electro-optical modulators with low half-wave voltage for CMOS compatibility.
• To advance thin-film lithium niobate photonic integrated circuit manufacturing for large-scale deployment.
• To demonstrate high-performance modulators within a small footprint.

Main Methods:

• Fabrication of folded electro-optical modulators using TFLN technology.
• Utilizing CSEM's open-access foundry process with standardized process design kit components.
• Device design and characterization at 1550 nm in TE polarization.

Main Results:

• Achieved a low half-wave voltage of 0.9 V.
• Demonstrated bandwidths exceeding 40 GHz.
• Fabricated compact modulators on a 5 mm × 5 mm chip.

Conclusions:

• Folded TFLN modulators offer a viable solution for compact, low-voltage, high-bandwidth photonic integrated circuits.
• The developed technology supports direct driving with CMOS circuits.
• Advancements in TFLN manufacturing are key for widespread adoption.