Compact polarizing beam splitter based on a metal-insulator-metal inserted into multimode interference coupler.

Area of Science:

• Optoelectronics
• Nanophotonics
• Integrated Optics

Background:

• Polarizing beam splitters (PBS) are essential optical components for manipulating light polarization.
• Conventional PBS designs often suffer from large footprints and complex fabrication processes.
• There is a need for compact and efficient PBS devices for integrated photonic applications.

Purpose of the Study:

• To propose and analyze a novel compact polarizing beam splitter (PBS).
• To investigate the performance of a PBS based on a metal-insulator-metal (MIM) structure integrated into a multimode interference coupler (MMI).
• To systematically study the influence of MIM structure parameters on PBS performance.

Main Methods:

• Utilizing a metal-insulator-metal (MIM) structure within a multimode interference coupler (MMI).
• Leveraging the cut-off condition for TE polarization reflection and surface plasmon polariton for TM polarization transmission.
• Employing a 3D finite-difference time-domain (FDTD) method for optical simulation and analysis.

Main Results:

• Achieved efficient separation of TE and TM polarized light.
• Demonstrated high transmittance (0.9) for TM light and high reflectance (0.88) for TE light.
• Obtained a high extinction ratio of 12.55 dB with low insertion losses (1.1 dB for TE, 0.9 dB for TM).
• The designed PBS exhibits a significantly reduced length of 44 µm.

Conclusions:

• The proposed compact PBS based on MIM-MMI structure offers efficient polarization splitting.
• The device's compact size and high performance make it suitable for integrated photonic systems.
• This design represents a significant advancement in miniaturizing PBS technology.