High-Efficiency Graphene-Silicon Slot-Waveguide Microring Modulator at 1.5 and 2 µm Wavelength Bands

Electro-optic (E/O) modulators are crucial for optical communication but face a trade-off between bandwidth and efficiency. Here, we present an integrated modulator that simultaneously achieves wideband, large bandwidth, and high efficiency operation by embedding a partially overlapped double-layer graphene on a compact silicon slot-waveguide microring resonator. At 1.5 $\mu m$ waveband, the modulator has a large bandwidth of over 70 GHz (setup limited), an active length of 10 $\mu m$, an insertion loss of 1.41 dB, an extinction ratio of 9.2 dB, and an OMA of −1.97 dBm under a 3-V voltage swing at 1549.023 nm (45 pm detuning). Anopen eye-diagram of 50 Gbit/s was obtained with a 2-V $V_{\text{pp}}$ RF drive voltage. At 2 $\mu m$ waveband, the modulator has a large bandwidth of over 20 GHz (setup limited), an extinction ratio of 9.3 dB, an insertion loss of 2.98 dB, an OMA of −3.36 dBm under a 6-V voltage swing, and an open eye diagram at 20 Gbit/s with a 2-V $V_{\text{pp}}$ RF drive voltage. The broadband, large bandwidth, compact, highly efficient, and energy efficient graphene E/O modulator has the potential to enable large-scale graphene photonic integrated circuits, facilitating a broad range of applications such as optical interconnects and programmable photonic circuits.