A compact and low loss Y-junction for submicron silicon waveguide.

Area of Science:

• Photonics
• Integrated Optics
• Nanophotonics

Background:

• Y-junctions are fundamental components in photonic integrated circuits.
• Existing Y-junction designs often suffer from high insertion loss and wavelength dependency.
• Miniaturization of photonic devices is crucial for advanced applications.

Purpose of the Study:

• To design and fabricate a compact, low-loss, and wavelength-insensitive Y-junction for submicron silicon waveguides.
• To achieve a device footprint significantly smaller than conventional Y-junctions.
• To validate performance using complementary metal-oxide-semiconductor (CMOS) compatible fabrication.

Main Methods:

• Utilized finite difference time-domain (FDTD) simulation for optical analysis.
• Employed particle swarm optimization (PSO) for device design.
• Fabricated the Y-junction using a 248 nm CMOS-compatible process.

Main Results:

• Achieved an average insertion loss of 0.28 ± 0.02 dB.
• Demonstrated wavelength insensitivity across the operational spectrum.
• Fabricated device footprint is less than 1.2 μm x 2 μm.
• Insertion loss was uniform across an 8-inch wafer.

Conclusions:

• The developed Y-junction offers superior performance in terms of loss and size.
• The compact and efficient design is suitable for dense photonic integration.
• CMOS compatibility ensures scalability for mass production.