Multilayer 3-D photonics in silicon.

Area of Science:

• Photonics and Optical Engineering
• Materials Science and Engineering
• Semiconductor Device Fabrication

Background:

• Three-dimensional (3-D) integration of photonic devices is crucial for advancing optical systems.
• Existing silicon photonics often face limitations in device density and functionality.
• Vertical integration of multiple silicon layers offers a promising pathway for complex photonic architectures.

Purpose of the Study:

• To report the development of 3-D integrated photonic structures in multiple silicon layers.
• To demonstrate a novel fabrication process for creating vertically stacked photonic devices.
• To showcase a multistage optical filter as a proof-of-concept for this 3-D integration technology.

Main Methods:

• Utilizing oxygen ion implantation into silicon-on-insulator substrates with patterned thermal oxide masks.
• Employing high-temperature annealing to form photonic structures within integrated silicon layers.
• Combining this process with epitaxial growth to achieve devices across three vertically integrated silicon layers.
• Fabricating a multistage optical filter with coupled microdisks and bus waveguides.

Main Results:

• Successfully created photonic structures on multiple, vertically integrated silicon layers.
• Demonstrated a multistage optical filter fabricated using the developed 3-D integration technique.
• Achieved extinction ratios exceeding 14 dB for the optical filter.
• Reported excess insertion loss of less than 1 dB for the device.

Conclusions:

• The reported method enables the fabrication of 3-D integrated photonic structures in silicon.
• Vertical integration of photonic devices on multiple silicon layers is feasible and effective.
• The demonstrated optical filter performance highlights the potential of this technology for advanced photonic applications.