Dispersion engineered high quality lithium niobate microring resonators.

Area of Science:

• Integrated photonics
• Materials science
• Nonlinear optics

Background:

• Lithium niobate (LN) possesses excellent material properties for diverse applications.
• Integrated photonics on chip-scale platforms offers advantages in device engineering and functionality.
• Precise control of group-velocity dispersion (GVD) is essential for nonlinear photonic applications.

Purpose of the Study:

• To demonstrate high-Q lithium niobate (LN) microring resonators.
• To achieve flexible control of GVD in both normal and anomalous dispersion regimes.
• To enable advanced nonlinear photonic applications using engineered GVD in LN microring resonators.

Main Methods:

• Fabrication of high-Q LN microring resonators.
• Tuning device cross-section to engineer GVD.
• Utilizing material birefringence for GVD control.
• Characterization of GVD in the telecom band.

Main Results:

• Achieved optical Q factors exceeding 1 million.
• Demonstrated flexible GVD control ranging from -0.128 ps²/m to 0.043 ps²/m.
• Obtained a small anomalous GVD of -0.015 ps²/m, lower than silica fiber.
• Showcased GVD tunability in both normal and anomalous regimes.

Conclusions:

• High-Q LN microring resonators with flexibly engineered GVD are demonstrated.
• The ability to precisely control GVD is a critical advancement for nonlinear photonics.
• This work paves the way for broader nonlinear photonic applications in high-Q LN microring resonators.