High-Speed and On-Chip Optical Switch Based on a Graphene Microheater

Area of Science:

• Photonics and optoelectronics
• Materials science
• Nanotechnology

Background:

• Graphene possesses unique optical, electronic, thermal, and mechanical properties, making it suitable for advanced optical devices.
• Traditional optical switches often rely on metal heaters, limiting their speed and efficiency.

Purpose of the Study:

• To demonstrate and characterize on-chip optical switches utilizing graphene microheaters.
• To investigate the modulation speed and efficiency of graphene-based optical switches.
• To assess the potential of these switches for high-performance silicon photonics.

Main Methods:

• Electromagnetic field calculations were used to design an optimal add/drop-type racetrack resonator structure.
• Graphene microheaters were fabricated directly onto the resonator of the optical switch.
• Optical transmission spectra and real-time high-speed operation were measured using a near-infrared camera.

Main Results:

• The graphene-based optical switch achieved a high wavelength tuning efficiency of 0.24 nm/mW.
• A high heating efficiency of 7.66 K·μm³ /mW was recorded.
• The device demonstrated high-speed modulation with 10%-90% rise and fall response times of 1.2 μs and 3.6 μs, respectively, operating at 100 kHz.

Conclusions:

• Graphene microheaters enable significantly faster optical switching compared to traditional metal heaters.
• The demonstrated on-chip optical switches offer high efficiency and speed, suitable for silicon photonics.
• These advancements are expected to drive progress in integrated optoelectronic applications.