Silicon-based polarization beam splitters with broadband subwavelength grating TM-pass polarizers

Area of Science:

• Photonics
• Integrated Optics
• Materials Science

Background:

• Polarization beam splitters (PBSs) are essential for controlling light polarization in photonic integrated circuits (PICs).
• Existing PBS designs often face limitations in bandwidth, footprint, or fabrication complexity.
• Efficient polarization management is critical for advanced PIC functionalities.

Purpose of the Study:

• To demonstrate a novel silicon-based PBS.
• To integrate a broadband subwavelength grating (SWG) TM-pass polarizer into the PBS design.
• To achieve high performance metrics including low insertion loss and excellent crosstalk over a wide wavelength range.

Main Methods:

• Fabrication of a silicon-based PBS incorporating a broadband SWG TM-pass polarizer.
• Experimental characterization of the PBS performance, including insertion loss (IL) and crosstalk (CT).
• Evaluation of device performance across a specific wavelength range (1500 nm to 1561 nm) for both TE and TM polarizations.

Main Results:

• Achieved insertion loss (IL) below 1 dB for both TE and TM polarizations.
• Demonstrated crosstalk (CT) exceeding 30 dB across the 1500 nm to 1561 nm wavelength range.
• Validated the broadband performance of the SWG TM-pass polarizer within the PBS.

Conclusions:

• The novel silicon PBS with an SWG TM-pass polarizer offers a promising solution for polarization management in PICs.
• The device exhibits a favorable balance between bandwidth, footprint, and fabrication complexity.
• Easy integration with standard silicon photonics platforms is a key advantage for practical applications.