High-Performance On-Chip Silicon Beamsplitter Based on Subwavelength Metamaterials for Enhanced Fabrication Tolerance

Area of Science:

• Photonics
• Integrated Circuits
• Materials Science

Background:

• Efficient power splitting is crucial for silicon photonic integrated circuits.
• Traditional Y-junctions face limitations in bandwidth, fabrication tolerance, and footprint.
• Fundamental mode losses occur in conventional Y-junctions due to fabrication resolution limits.

Purpose of the Study:

• To propose and validate a high-performance Y-junction power splitter.
• To overcome the limitations of existing power-division architectures.
• To leverage subwavelength metamaterials for improved performance.

Main Methods:

• Full three-dimensional simulations were performed.
• Optimization was conducted for specific fabrication resolutions (50 nm and 100 nm).
• Fabrication tolerances were analyzed, and a proof-of-concept device was experimentally validated.

Main Results:

• Simulations show fundamental mode excess loss below 0.1 dB over a 300 nm bandwidth (1400-1700 nm) for 50 nm resolution.
• Extended bandwidth of 350 nm (1350-1700 nm) with <0.3 dB loss for 100 nm resolution.
• Experimental results demonstrated <0.2 dB excess loss in a 195 nm bandwidth for 50 nm resolution.

Conclusions:

• The proposed subwavelength metamaterial Y-junction offers ultra-broadband, low-loss power splitting.
• The design exhibits robust performance against fabrication errors.
• This advancement holds promise for next-generation silicon photonic integrated circuits.