Polarization rotator-splitters and controllers in a Si3N4-on-SOI integrated photonics platform

Area of Science:

• Integrated photonics
• Materials science
• Optical engineering

Background:

• Silicon nitride (Si(3)N(4)) on silicon-on-insulator (SOI) platforms offer unique properties for integrated photonics.
• Effective polarization management is crucial for advanced photonic integrated circuits.
• Existing polarization control methods often face limitations in bandwidth and performance.

Purpose of the Study:

• To demonstrate novel polarization management devices utilizing a custom Si(3)N(4) on SOI platform.
• To develop a broadband polarization rotator-splitter based on mode conversion.
• To engineer a functional polarization controller using integrated optical components.

Main Methods:

• Fabrication of Si(3)N(4) waveguides on a SOI platform.
• Design and implementation of a TM0-TE1 mode converter for polarization rotation.
• Integration of rotator-splitters, MMI couplers, and thin-film heaters for polarization control.

Main Results:

• Demonstrated a broadband polarization rotator-splitter with performance metrics: polarization crosstalk < -19 dB, insertion loss < 1.5 dB, and polarization dependent loss < 1.0 dB over an 80 nm bandwidth.
• Successfully fabricated and tested a polarization controller integrated with the rotator-splitter.
• Validated the effectiveness of the composite Si(3)N(4)-silicon waveguide design for polarization manipulation.

Conclusions:

• The developed Si(3)N(4) on SOI platform enables high-performance polarization management devices.
• The novel rotator-splitter design offers broadband operation with low loss and crosstalk.
• These devices are promising for advanced applications in optical communication and sensing.