Polarization-insensitive arrayed-waveguide grating wavelength multiplexer on silicon

Area of Science:

• Photonics
• Optical Engineering
• Materials Science

Background:

• Polarization dependence in optical devices can limit performance.
• Arrayed-waveguide gratings (AWGs) are key components in wavelength-division multiplexing (WDM).
• Silica-based waveguides on silicon offer a robust platform for integrated optics.

Purpose of the Study:

• To demonstrate a novel wavelength-division multiplexer (WDM) with zero polarization dependence.
• To achieve high wavelength resolution and low crosstalk for dense optical communication systems.
• To integrate polarization insensitivity into an arrayed-waveguide grating (AWG) device.

Main Methods:

• Fabrication of an arrayed-waveguide grating (AWG) using silica-based optical waveguides on a silicon substrate.
• Insertion of a quartz half-wave (λ/2) plate within the AWG to counteract waveguide birefringence.
• Design of the AWG to operate at a high diffraction order (115th) for enhanced spectral resolution.

Main Results:

• Achieved a polarization-independent wavelength-division multiplexer (WDM).
• Successfully multiplexed 13 wavelength channels with a 1-nm channel spacing.
• Demonstrated a narrow passband width of 0.3 nm and a crosstalk level of -30 dB.
• Verified the effectiveness of the quartz λ/2 plate in eliminating polarization dependence.

Conclusions:

• The developed AWG is highly effective for polarization-insensitive WDM applications.
• The integration of a quartz λ/2 plate is a viable method to achieve polarization insensitivity in AWGs.
• The device's performance metrics (resolution, crosstalk, channel capacity) are suitable for advanced optical communication networks.