Adiabatically widened silicon microrings for improved variation tolerance.

Area of Science:

• Photonics
• Integrated Optics
• Semiconductor Device Fabrication

Background:

• Microring resonators are key components in photonic integrated circuits.
• Dimensional variations in fabrication significantly impact microring performance, particularly resonance wavelength.
• Conventional microring designs with uniform waveguides are sensitive to these variations.

Purpose of the Study:

• To investigate the fabrication tolerance of silicon microrings with adiabatically widened bends.
• To compare the dimensional variation tolerance of this new design against conventional uniform waveguide microrings.
• To demonstrate improvements in resonance wavelength stability through wafer-scale measurements.

Main Methods:

• Fabrication of test structures using IMEC Standard Passives process (193 nm DUV lithography, 200 mm SOI wafer).
• Design of silicon microrings featuring adiabatically widened bends.
• Wafer-scale measurement of resonance wavelengths for fabricated structures.

Main Results:

• Silicon microrings with adiabatically widened bends exhibit enhanced tolerance to dimensional variations.
• Significant improvements in intra-die and wafer-scale resonance wavelength variation were observed.
• A 2.1× reduction in the standard deviation of the resonance wavelength across the wafer was achieved compared to conventional designs.

Conclusions:

• Adiabatically widened bends offer a robust solution for improving microring resonator fabrication tolerance.
• This design advancement leads to more stable and predictable photonic integrated circuit performance.
• The findings are crucial for scalable manufacturing of silicon photonics devices.