Metamaterial-waveguide bends with effective bend radius < λ₀/2

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Nanotechnology

Background:

• Efficient light routing is crucial for advanced photonic integrated circuits.
• Miniaturization of photonic components is essential for large-scale integration.
• Metamaterials offer unique optical properties for novel device designs.

Purpose of the Study:

• To design, fabricate, and characterize broadband, efficient all-dielectric metamaterial-waveguide bends (MWBs).
• To achieve 180-degree light redirection in compact footprints.
• To enable robust and scalable photonic integration solutions.

Main Methods:

• Design and simulation of all-dielectric metamaterial structures.
• Fabrication of metamaterial-waveguide bends using advanced lithography.
• Characterization of transmission efficiency and operating bandwidth through optical measurements.

Main Results:

• Demonstrated MWBs with footprints as small as 3 μm × 3 μm.
• Achieved 180-degree light redirection with effective bend radii below λ₀/2.
• Obtained high transmission efficiencies (>80% designed, ~70% measured).
• Exhibited broad operating bandwidths (>66 nm designed, >56 nm measured).

Conclusions:

• The developed MWBs are efficient and broadband, suitable for compact photonic devices.
• The design methodology, incorporating fabrication constraints, yields robust devices.
• This approach can be extended for general light routing in dense photonic integrated circuits.