Integrated polarization beam splitter with relaxed fabrication tolerances

Area of Science:

• Photonics
• Integrated Optics
• Materials Science

Background:

• Polarization handling is crucial for next-generation photonic integrated circuits (PICs).
• Existing integrated polarization beam splitters (PBS) face challenges due to poor fabrication tolerances, limiting their widespread use.
• Effective polarization management is essential for advanced optical functionalities in PICs.

Purpose of the Study:

• To develop a novel, highly fabrication-tolerant polarization beam splitter (PBS) for photonic integrated circuits (PICs).
• To engineer a PBS design that significantly reduces sensitivity to critical fabrication errors.
• To demonstrate a passive PBS solution suitable for mass production in PICs.

Main Methods:

• The study utilizes an asymmetrical Mach-Zehnder interferometer (MZI) as the core structure.
• A Si/SiO(2) Periodic Layer Structure (PLS) is integrated onto one arm of the MZI.
• Birefringence engineering of the PLS is employed to control MZI arm properties and reduce error sensitivity.

Main Results:

• The proposed PBS demonstrates high tolerance to waveguide width variations, up to 400nm.
• A polarization extinction ratio (PER) exceeding 13dB is maintained across the entire C-Band.
• The design is fully passive, simplifying integration and reducing power consumption.

Conclusions:

• The developed PBS offers a robust solution for polarization management in PICs.
• The fabrication tolerance of this design overcomes a major hurdle for integrated optics.
• This breakthrough enables more reliable and high-performance photonic integrated circuits.