Broadband low-crosstalk compact waveguides enabled by anisotropic metamaterial substrate.

Area of Science:

• Photonics
• Materials Science
• Nanotechnology

Background:

• Waveguide crosstalk limits integration density in photonic chips.
• Conventional methods focus on cladding layer engineering for crosstalk suppression.

Purpose of the Study:

• To investigate the role of substrate engineering in mitigating waveguide crosstalk.
• To demonstrate a novel approach for broadband crosstalk suppression using metamaterial substrates.

Main Methods:

• Designing anisotropic metamaterial substrates.
• Simulating evanescent wave suppression within the substrate.
• Analyzing crosstalk in coupled silicon strip waveguides.

Main Results:

• Anisotropic metamaterial substrates significantly suppress substrate-coupled evanescent waves.
• Achieved crosstalk below -20 dB for fundamental mode across 1300-1637 nm wavelength range.
• Demonstrated applicability to bending waveguides and waveguide arrays.

Conclusions:

• Substrate engineering is critical for effective waveguide crosstalk mitigation.
• Metamaterial substrates offer a viable strategy for broadband crosstalk suppression.
• This approach enables the development of ultra-compact integrated photonic chips.