Graphene oxide-based waveguide polariser: from thin film to quasi-bulk

Area of Science:

• Materials Science
• Optical Engineering
• Nanotechnology

Background:

• Optical polarizers are crucial components in various photonic applications.
• Existing waveguide polarizers often face limitations in extinction ratio, bandwidth, or fabrication complexity.
• Graphene-based materials offer unique optical properties for advanced photonic devices.

Purpose of the Study:

• To demonstrate a broadband waveguide polarizer utilizing graphene oxide.
• To achieve a high extinction ratio using a cost-effective fabrication method.
• To investigate the underlying principles of polarization-dependent loss in graphene oxide waveguides.

Main Methods:

• Fabrication of a polymer optical waveguide.
• Coating the waveguide with graphene oxide using the drop-casting method.
• Characterization of the device's extinction ratio across a broadband wavelength range.
• Analysis of the anisotropic complex dielectric function of the graphene oxide film.

Main Results:

• Demonstrated a broadband waveguide polarizer with a high extinction ratio.
• Achieved a maximum extinction ratio of nearly 40 dB at 1590 nm.
• Observed a low variation of 4.5 dB across the 1530 nm to 1630 nm wavelength range.
• The device utilized a short graphene oxide coating (1.3 mm) and thin film (2.0 µm).

Conclusions:

• The developed graphene oxide waveguide polarizer exhibits the highest reported extinction ratio for graphene-based devices.
• The results are attributed to the anisotropic complex dielectric function of the graphene oxide film, leading to polarization-dependent loss.
• This technology holds promise for advanced optical communication and sensing applications.