Polarization-insensitive and compact single-mode filter on a 340 nm silicon-on-insulator platform.

Area of Science:

• Photonics
• Integrated Optics
• Materials Science

Background:

• Silicon-on-insulator (SOI) technology is a key platform for integrated photonics.
• Developing polarization-insensitive optical filters is crucial for robust photonic systems.
• Existing single-mode filters often face limitations in bandwidth, footprint, or polarization dependence.

Purpose of the Study:

• To propose and demonstrate a novel polarization-insensitive single-mode filter (SMF).
• To achieve a compact footprint and broad operational bandwidth.
• To validate performance metrics including excess loss and extinction ratio.

Main Methods:

• Utilizing a 340 nm SOI platform.
• Implementing a design with two lateral coupling waveguides.
• Coupling high-order modes from a central waveguide to lateral waveguides.

Main Results:

• Fabricated SMF exhibits polarization-insensitivity.
• Achieved excess loss below 0.29 dB.
• Demonstrated extinction ratio exceeding 20 dB.
• Observed a broad operational bandwidth of 136 nm.
• Device footprint is less than 13 µm.

Conclusions:

• The proposed integrated SMF effectively suppresses polarization dependence.
• The device offers excellent performance metrics (low loss, high extinction ratio, broad bandwidth) in a compact size.
• This technology holds significant potential for advanced silicon photonic integrated circuits.