Graphene-Loaded LiNbO₃ Directional Coupler: Characteristics and Potential Applications

Area of Science:

• Integrated Photonics
• Materials Science
• Nanotechnology

Background:

• Lithium niobate (LiNbO3, LN) is a key material for integrated photonics due to its electro-optic properties.
• Graphene offers unique electronic and optical properties with potential for device enhancement.
• Developing hybrid materials can lead to novel photonic functionalities.

Purpose of the Study:

• To investigate the effect of graphene integration on lithium niobate (LN) ridge waveguides and directional couplers.
• To analyze changes in coupling efficiency, light absorption, and temperature sensitivity.
• To explore the potential of graphene-LN hybrid devices for photonic applications.

Main Methods:

• Experimental fabrication of graphene-loaded LN waveguides.
• Optical characterization of coupling efficiency and polarization-dependent absorption.
• Temperature-dependent measurements of device performance.
• Simulation of optical mode behavior in hybrid structures.

Main Results:

• Graphene integration significantly alters the effective mode refractive index of LN waveguides.
• Enhanced waveguide coupling and precise control over light transmission were achieved.
• Graphene-LN structures exhibited strong thermal sensitivity, affecting output power ratios.
• Polarization-dependent light absorption was observed due to graphene loading.

Conclusions:

• Graphene-LN hybrid devices demonstrate potential for compact, high-performance photonic circuits.
• The observed thermal sensitivity makes these devices suitable for temperature sensing.
• Findings provide insights for designing advanced integrated photonic systems for optical communication and quantum technologies.