Ultra-miniaturized Bloch mode metasplitters for one-dimensional grating waveguides

Area of Science:

• Photonics
• Metamaterials
• Integrated Optics

Background:

• One-dimensional grating waveguides (1DGWs) are crucial for integrated photonics.
• Existing multi-channel configurations often require complex designs and transition regions.
• Controlling Bloch mode profiles and dispersion is essential for device performance.

Purpose of the Study:

• To introduce novel, ultra-miniaturized power splitters with multiple output channels integrated into 1DGWs.
• To maintain unperturbed crystal lattice-sensitive Bloch mode profiles across all output channels.
• To simplify multi-channel 1DGW configurations and maximize chip area utilization.

Main Methods:

• Utilized a pixelated metamaterial approach for device design.
• Integrated a time-domain heuristic algorithm for optimization.
• Fabricated and experimentally characterized 1x2 and 1x3 metasplitters.

Main Results:

• Achieved ultra-miniaturized footprint (2.1 × 2.2 μm²).
• Demonstrated average minimum losses per channel of 3.80 dB (1x2) and 5.36 dB (1x3), close to ideal splitting.
• Exhibited a 1 dB bandwidth of 15 nm with excellent uniformity across output channels.

Conclusions:

• The developed metasplitters offer a simplified approach to multi-channel 1DGWs.
• These devices are suitable for ultrahigh-bandwidth, densely integrated photonic circuits.
• The designs are valuable for applications requiring precise control of light, including slow light phenomena.