Advanced photonic modulation with graphene
Researchers have demonstrated the first graphene-based I/Q modulator integrated with silicon photonics capable of advanced modulation formats. Specifically, the authors successfully implemented a quadrature phase-shift keying (QPSK) modulation at rates up to 40 Gb/s using a nested Mach-Zehnder interferometer (MZI) equipped with four double-layer graphene electro-absorption modulators (EAMs). The device exploits graphene’s ultrafast, broadband, and energy-efficient properties to achieve high-speed and high-capacity coherent modulation, paving the way for its application in high-data-rate optical communication systems. The paper was published in ACS Photonics.
Image: Graphene-improved photonic modulator.
Graphene improves the performance of silicon photonics modulators through its exceptional electronic and optical properties. Specifically, graphene’s high carrier mobility enables ultrafast modulation capabilities, allowing devices to operate at hundreds of gigahertz frequencies. Its broadband optical absorption and tunability of the chemical potential via electrostatic gating facilitate efficient amplitude and phase modulation across a wide wavelength range. Additionally, graphene's atomic thinness enables highly compact device designs with minimal footprint, making integration with silicon photonics scalable and energy-efficient. These features collectively enable high-speed, low-power, and broadband modulation performance in integrated photonic systems.
The authors designed and built a new kind of miniature optical device that can encode data onto light signals quickly and efficiently. Their approach involved creating a special circuit on a silicon chip, which is similar to the microchips used in computers, but with added layers of graphene—a super-thin, highly conductive material known for its excellent electronic and optical properties. The graphene was produced by Graphenea.
This process demonstrated that the graphene-based device could operate at high speeds, using less energy, and over a broad range of wavelengths, making it promising for future ultra-fast communication systems.
