Ultra-narrow, highly efficient power splitters and waveguides that exploit the TE₀₁ Mie-resonant bandgap

Area of Science:

• Photonics
• Optical Engineering
• Materials Science

Background:

• Developing compact and efficient components is essential for advancing optical integrated circuits.
• All-dielectric nanophotonic devices offer unique properties for light manipulation.

Purpose of the Study:

• To design and simulate ultra-narrow waveguides and optical power splitters using germanium rods.
• To investigate the impact of position disordering on device performance.

Main Methods:

• Utilized finite-difference time-domain (FDTD) numerical simulations.
• Designed straight, Ω-shaped, Y-shaped, and T-shaped structures with germanium rods in air.
• Analyzed transmission efficiency and tolerance to position disordering.

Main Results:

• Achieved 90% optical transmission for straight and Ω-shaped waveguides at a normalized frequency of a/λ=0.327.
• Obtained >46% transmission for Y-shaped and T-shaped power splitters per branch.
• Demonstrated tolerance to 10% position disordering for waveguides with four rows of rods.

Conclusions:

• The proposed ultra-narrow waveguides and power splitters are highly efficient.
• These devices are suitable for high-density, all-dielectric optical integrated circuits.
• The designs show robustness against fabrication imperfections.