Channel Waveguides in Lithium Niobate and Lithium Tantalate

Area of Science:

• Integrated Optics
• Materials Science
• Nonlinear Optics

Background:

• Lithium niobate (LiNbO3) is a key material for integrated optics due to its excellent nonlinear optical properties.
• Fabricating high-quality LiNbO3 waveguides with low propagation losses is crucial for advanced photonic devices.

Purpose of the Study:

• To develop a fabrication method for low-loss lithium niobate channel waveguides.
• To characterize the optical properties and nonlinear performance of the fabricated waveguides.

Main Methods:

• Utilized laser-driven rapid-prototyping for precise machining of LiNbO3 and lithium tantalate substrates.
• Employed liquid phase epitaxy with K2O flux to grow high-quality single-crystal LiNbO3 channels.
• Measured surface roughness and propagation losses at 633 nm.

Main Results:

• Achieved LiNbO3 channel waveguides on LiNbO3 and LiTaO3 substrates.
• Measured a low propagation loss of 0.26 ± 0.04 dB/mm at 633 nm.
• Demonstrated second harmonic generation at 980 nm, confirming nonlinear optical activity.

Conclusions:

• The combined laser processing and liquid phase epitaxy technique enables fabrication of high-quality LiNbO3 waveguides.
• These waveguides exhibit low propagation losses and retain essential nonlinear optical properties for integrated photonic applications.