Simple production of membrane-based LiNbO₃ micro-modulators with integrated tapers

Area of Science:

• Photonics and optical engineering.
• Materials science and engineering.

Background:

• Lithium niobate (LiNbO3) is a key material for electro-optical devices.
• Existing fabrication methods can be complex and costly.
• Achieving precise thickness control and integrated features is challenging.

Purpose of the Study:

• To develop a cost-effective method for fabricating free-standing LiNbO3 waveguides with integrated tapers.
• To demonstrate the utility of these structures for compact electro-optical components.
• To achieve precise membrane thickness control for optimized performance.

Main Methods:

• Utilizing optical grade dicing to create free-standing LiNbO3 membranes.
• Integrating tapers that function as spot-size converters during the dicing process.
• Achieving calibrated membrane thicknesses ranging from 450 to 500 μm.

Main Results:

• Successfully fabricated free-standing LiNbO3 waveguides with integrated tapers.
• Demonstrated simultaneous production of calibrated membranes and tapers.
• Achieved low insertion losses due to integrated tapers.
• Showcased a 200 μm-long electro-optical Fabry-Perot with a figure of merit of 0.19 V·cm in a 4.5 μm-thick membrane.

Conclusions:

• Optical grade dicing offers a viable route for low-cost production of advanced LiNbO3 components.
• The developed method facilitates the creation of compact and low-power electro-optical devices.
• This technique paves the way for novel integrated photonic applications using thin LiNbO3 membranes.