Ultra-compact polarization beam splitter utilizing a graphene-based asymmetrical directional coupler

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Nanotechnology

Background:

• Polarization beam splitters (PBS) are crucial components in optical systems.
• Existing PBS designs often face limitations in size, performance, or tunability.
• Graphene's unique optical properties offer potential for novel photonic devices.

Purpose of the Study:

• To propose and investigate a novel ultra-compact polarization beam splitter (PBS).
• To utilize an asymmetrical directional coupler combining silicon and graphene waveguides.
• To achieve high performance and tunable power splitting for on-chip optical signal processing.

Main Methods:

• Design and simulation of an asymmetrical directional coupler.
• Integration of a silicon waveguide (SW) with a graphene multilayer embedded silicon waveguide (GMESW).
• Analysis of modal characteristics for TE and TM modes in the hybrid waveguide structure.

Main Results:

• The proposed PBS demonstrates significant modal variation for TM mode and slight variation for TE mode.
• Achieved high extinction ratios of 18.2 dB and 21.2 dB for thru and cross ports.
• Obtained low insertion losses of 0.16 dB and 0.36 dB for thru and cross ports, respectively.
• Demonstrated tunable power splitting for TM mode by adjusting graphene's chemical potential.

Conclusions:

• The novel ultra-compact PBS based on SW and GMESW offers excellent performance.
• The device's tunable power splitting capability opens avenues for advanced optical signal processing.
• This work contributes to the development of miniaturized and versatile photonic integrated circuits.