Broadband TE-pass slot waveguide polarizer using an asymmetrical directional coupler

Area of Science:

• Photonics
• Nanotechnology
• Optical Engineering

Background:

• Silicon photonics enables miniaturized optical devices.
• Efficient polarizers are crucial for optical signal processing.
• Hybrid plasmonic waveguides offer unique light confinement properties.

Purpose of the Study:

• To numerically propose a compact TE-pass polarizer for silicon-based slot waveguides.
• To achieve high extinction ratio and low insertion loss for optical filtering.
• To investigate the performance and fabrication tolerances of the proposed device.

Main Methods:

• Numerical simulation of a directional coupler integrating asymmetrical slot waveguide (ASW) and hybrid plasmonic waveguide (HPW).
• Utilizing modal birefringence in ASW for mode selectivity.
• Analyzing TE and TM mode coupling and attenuation characteristics.

Main Results:

• Achieved a TE-pass polarizer with an extinction ratio (ER) of 45 dB and insertion loss (IL) of 0.44 dB at 1.55 μm.
• Demonstrated a bandwidth exceeding 130 nm with ER > 30 dB and IL < 1 dB.
• Analyzed fabrication tolerances and field evolution along the propagation distance.

Conclusions:

• The proposed compact TE-pass polarizer demonstrates excellent performance metrics.
• The device is suitable for integration into silicon photonic circuits.
• The design offers a promising solution for efficient optical polarization control.