Ultra-sensitive thin-film lithium niobate electric field sensor based on a folded Mach-Zehnder interferometer

Area of Science:

• Physics
• Materials Science
• Electrical Engineering

Background:

• Electric field (E-field) sensing is crucial for scientific research and engineering.
• Existing E-field sensors often lack the high sensitivity required for detecting faint signals.
• Thin-film lithium niobate (TFLN) technology offers potential advantages for sensor development.

Purpose of the Study:

• To demonstrate a high-sensitivity TFLN E-field sensor.
• To overcome the sensitivity limitations of conventional Mach-Zehnder interferometer (MZI) sensors.
• To achieve a record sensitivity in E-field sensing.

Main Methods:

• Fabrication of a TFLN E-field sensor utilizing a folded Mach-Zehnder interferometer (MZI) design.
• Integration of a segmented electrode within the MZI structure.
• Characterization of sensor performance across a frequency range of 10 MHz to 550 MHz.

Main Results:

• The folded MZI design with a segmented electrode significantly extends the effective modulation length.
• The sensor operates effectively within the 10 MHz to 550 MHz frequency range.
• A record sensitivity of 3.25 μV/m/Hz^1/2 was achieved at 75 MHz for MZI-based sensors.

Conclusions:

• The demonstrated TFLN E-field sensor offers high sensitivity and operates over a wide frequency range.
• The folded MZI architecture with segmented electrodes is effective in enhancing sensor performance.
• This advancement pushes the boundaries for sensitive E-field detection in various applications.