Graphene Thermal Infrared Emitters Integrated into Silicon Photonic Waveguides

Area of Science:

• Photonics
• Materials Science
• Nanotechnology

Background:

• Broadband mid-infrared (mid-IR) sources are crucial for photonic integrated circuits (PICs).
• Existing semiconductor-based mid-IR emitters face challenges in PIC compatibility, cost, and bandwidth.
• Ideal thermal emitters should couple efficiently into PIC waveguides and operate at high temperatures.

Purpose of the Study:

• To demonstrate graphene as a cost-efficient, integrable broadband mid-IR emitter for PICs.
• To integrate graphene emitters with silicon photonic waveguides for enhanced mid-IR light coupling.
• To achieve efficient coupling into the fundamental mode of silicon waveguides for gas sensing applications.

Main Methods:

• Integration of graphene emitters with silicon photonic waveguides.
• Characterization of broadband emission intensity from waveguide-integrated graphene.
• Utilizing grating couplers to confirm light coupling into waveguide modes.
• Performing thermal simulations to predict emitter operating temperatures.

Main Results:

• High broadband emission intensity observed from waveguide-integrated graphene emitters.
• Successful coupling of emitted light into the fundamental mode of silicon waveguides confirmed.
• Emitter temperatures up to 1000 °C predicted, enabling blackbody radiation across the mid-IR spectrum.
• Estimated coupling efficiency (η) of up to 68%, surpassing previously reported values for similar devices.

Conclusions:

• Graphene is a promising material for cost-efficient, high-performance broadband mid-IR emitters in PICs.
• Waveguide-integrated graphene emitters demonstrate superior coupling efficiency into silicon waveguides.
• The developed technology holds significant potential for advancing gas sensing and other mid-IR photonic applications.