Compact reconfigurable polarization converter based on phase-change subwavelength tilted grating

Area of Science:

• Photonics and Optical Engineering
• Materials Science

Background:

• Subwavelength gratings modulate waveguide modes but have limited modulation space.
• Phase change materials (PCMs) offer higher modulation efficiency for optical devices.

Purpose of the Study:

• To propose and investigate a compact, reconfigurable polarization converter utilizing PCMs in a subwavelength tilted grating structure.
• To explore the effects of tilted angles on effective refractive indices for TE and TM modes.

Main Methods:

• Systematic investigation of tilted angle effects on effective refractive indices.
• Utilizing the reversible crystalline-amorphous transition of PCMs for device reconfiguration.
• Analyzing mode coupling and conversion efficiency between TE0 and TM0 modes.

Main Results:

• Achieved efficient TE0 to TM0 mode conversion via controlled PCM states and grating perturbation.
• Demonstrated a small coupling length (17.89μm) and low insertion loss (<1.5 dB).
• Exhibited high conversion efficiency and mode purity across a broad wavelength range (1500-1600 nm) with 21-level tunability.

Conclusions:

• The proposed device offers a feasible solution for polarization sensitivity in silicon photonics.
• The multistage tunability shows potential for applications in neuromorphic computing networks.