High-alignment-accuracy transfer printing of passive silicon waveguide structures.

Area of Science:

• Photonics
• Materials Science
• Nanotechnology

Background:

• Silicon photonics enables integrated optical circuits.
• Precise alignment of discrete silicon devices onto waveguides is challenging.
• Existing methods may lack accuracy or scalability.

Purpose of the Study:

• To demonstrate a novel transfer printing technique for passive silicon devices.
• To achieve high-accuracy alignment of silicon devices onto silicon-on-insulator (SOI) waveguides.
• To characterize the coupling performance of printed devices at different wavelengths.

Main Methods:

• Transfer printing of passive silicon devices using a PDMS stamp.
• Underetching the buried oxide layer for device release.
• Designing adiabatic taper and directional coupler structures for 1310 nm and 1600 nm wavelengths.
• Utilizing tethers for controlled release and precise placement.

Main Results:

• Successful transfer printing of silicon devices onto SOI target wafers with high alignment accuracy.
• Achieved coupling losses of -1.5 +/- 0.5 dB for adiabatic tapers at 1310 nm.
• Achieved coupling losses of -0.5 +/- 0.5 dB for directional couplers at 1600 nm.
• Demonstrated misalignment tolerance of ± 1 µm for designed structures.

Conclusions:

• Transfer printing is a viable method for integrating passive silicon photonic devices.
• The developed technique offers high precision and low coupling losses.
• This approach is promising for advanced silicon photonic integrated circuits.