Waveguide design for a TFLN platform at 1064 nm for applications in spacecom and spectroscopy

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Integrated Optics

Background:

• Thin Film Lithium Niobate (TFLN) is a key material for optical applications at 1064 nm.
• Waveguide design and optimization are crucial for TFLN devices, especially at 1 µm.
• Existing TFLN waveguide designs lack comprehensive optimization for the 1064 nm spectral region.

Purpose of the Study:

• To compare the performance of etched and rib-loaded TFLN waveguides at 1064 nm.
• To analyze optical losses, modulation efficiency, and polarization mixing in different TFLN waveguide geometries.
• To identify optimal waveguide designs for phase modulator applications.

Main Methods:

• Numerical simulations were employed to analyze waveguide performance.
• The Payne-Lacey model was used to calculate scattering losses, considering waveguide roughness from AFM and visible spectrum measurements.
• Finite-Difference Time-Domain (FDTD) simulations assessed polarization mixing in 90-degree curves.

Main Results:

• Etched rib-loaded TFLN waveguides exhibit reduced polarization mixing compared to purely etched designs.
• Lower optical losses were observed in etched rib-loaded waveguides.
• High electro-optic (EO) modulation efficiency was achieved with optimized designs.

Conclusions:

• Etched rib-loaded TFLN waveguides offer superior performance for phase modulators at 1064 nm.
• Despite fabrication complexity, etched rib-loaded designs provide enhanced efficiency and reduced polarization issues.
• This research contributes to the advancement of TFLN-based photonic devices for high-performance optical communication and sensing.