Polarization-dependent tuning of Bragg reflection enabled through tilted subwavelength grating waveguide Bragg...

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Nanophotonics

Background:

• Waveguide Bragg gratings (WBGs) are crucial for optical signal processing.
• Subwavelength gratings (SWGs) offer unique optical properties.
• Controlling polarization-dependent spectral responses in WBGs is challenging.

Purpose of the Study:

• To propose and experimentally demonstrate tilted SWG WBGs.
• To achieve polarization-dependent tuning of spectral responses.
• To enable polarization-selective wavelength management in integrated devices.

Main Methods:

• Fabrication of tilted subwavelength grating (SWG) waveguide Bragg gratings (WBGs).
• Experimental characterization of spectral responses for transverse electric (TE) and transverse magnetic (TM) modes.
• Optimization of duty cycle and tilting angles for spectral tuning.

Main Results:

• Achieved polarization-dependent spectral tuning by tilting SWG segments.
• Observed a blueshift of 7 nm (5° tilt) and 35 nm (30° tilt) for TE modes.
• Maintained minimal Bragg wavelength shift (<0.5 nm) for TM modes.

Conclusions:

• Tilted SWG WBGs offer a novel approach for polarization management.
• Demonstrated polarization-dependent wavelength selectivity in integrated WBG devices.
• Provides a new tool for advanced optical signal processing and filtering.