Ultracompact silicon-on-insulator polarization rotator for polarization-diversified circuits

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Semiconductor Devices

Background:

• Polarization control is crucial for integrated photonic circuits.
• Existing polarization rotators often lack compactness or efficiency.
• Silicon-on-insulator (SOI) platform offers advantages for miniaturization and CMOS compatibility.

Purpose of the Study:

• To design and simulate an ultracompact and high-efficiency polarization rotator.
• To enable polarization-diversified circuits on a silicon platform.
• To achieve broadband operation with low insertion loss and high extinction ratio.

Main Methods:

• Utilized a bilevel-tapered TM0-to-TE1 mode converter.
• Incorporated a novel bent-tapered TE1-to-TE0 mode converter.
• Simulated performance using optical modeling software.

Main Results:

• Achieved an ultracompact device length of 15.3 μm.
• Demonstrated polarization conversion loss below 0.2 dB.
• Obtained a polarization-extinction ratio exceeding 25 dB over an 80 nm bandwidth around 1550 nm.
• Utilized SiO2 top-cladding for enhanced performance.

Conclusions:

• The proposed rotator is highly efficient and compact, suitable for polarization-diversified circuits.
• The design is compatible with standard CMOS fabrication processes.
• This device represents a significant advancement for integrated photonic applications requiring precise polarization control.