Polarization-Independent Optoelectronic Modulator Based on Graphene Ridge Structure

Area of Science:

• Photonics
• Materials Science
• Electrical Engineering

Background:

• Optoelectronic modulators are crucial for optical communication systems.
• Graphene's unique electrical and optical properties offer potential for advanced photonic devices.
• Achieving polarization-independent modulation remains a challenge in modulator design.

Purpose of the Study:

• To propose and simulate a novel polarization-independent optoelectronic modulator.
• To leverage the electrical absorption effect of graphene for optical modulation.
• To demonstrate high performance in both transverse magnetic (TM) and transverse electric (TE) modes.

Main Methods:

• Utilizing COMSOL Multiphysics for device structure design and simulation.
• Employing the finite element method (FEM) for analyzing the optical characteristics.
• Investigating the impact of applied voltage on graphene's equivalent refractive index and absorption.

Main Results:

• A double-layer graphene ridge structure in a silicon-based waveguide was designed.
• Near-identical extinction coefficients for TE and TM modes were achieved.
• Extinction ratios up to 110 dB were obtained across a wide communication band (1550 nm wavelength).
• A bandwidth of 173.78 GHz and a low insertion loss of 0.0338 dB were demonstrated.

Conclusions:

• The proposed graphene modulator effectively overcomes polarization dependency.
• The device exhibits excellent performance metrics, including high extinction ratio and broad bandwidth.
• This design presents a promising solution for next-generation high-speed optical communication systems.