Ultra-broadband silicon polarization splitter-rotator based on the multi-mode waveguide

Area of Science:

• Photonics
• Integrated Optics
• Semiconductor Devices

Background:

• Polarization splitter-rotators (PSRs) are essential components in photonic integrated circuits.
• Achieving ultra-broadband operation and simple fabrication remains a challenge for current PSR designs.

Purpose of the Study:

• To propose and demonstrate a novel ultra-broadband polarization splitter-rotator (PSR).
• To achieve high performance using a simplified fabrication process on the Silicon-On-Insulator (SOI) platform.

Main Methods:

• The PSR design integrates a straight multi-mode waveguide, an asymmetrical directional coupler, and a bent directional coupler.
• A multi-mode waveguide facilitates efficient TM0-TE1 polarization rotation.
• Asymmetrical and bent directional couplers manage mode conversion and filtering.

Main Results:

• The fabricated PSR exhibits a high extinction ratio exceeding 30.82 dB and low insertion loss below 0.57 dB at the central wavelength.
• An extinction ratio greater than 20 dB is maintained over an ultra-broad wavelength band exceeding 85 nm.
• The device requires only a single etching step for fabrication.

Conclusions:

• The proposed PSR design offers a promising solution for ultra-broadband polarization control in photonic integrated circuits.
• The simplified fabrication process on the SOI platform enhances its practicality for mass production.
• This advancement contributes to the development of more efficient and versatile photonic devices.