Chip-integrated double-layer graphene EO modulators. (A) Schematic illustration of a double-layer graphene modulator; (B) static response of the modulator; (C) the graphene band profiles (green for unoccupied state, red for occupied states) for regions I, II, and III in (B) [43]; (D) diagram of a high-speed double-layer graphene modulator; (E) EO S₂₁ bandwidth of the double-layer graphene optical modulator; (F) eye diagrams at data rates of 10 and 50 Gb s⁻¹ [47]. (A–C) Adapted with permission from [43]. Copyright 2012, American Chemical Society. (D–F) Adapted with permission from [47]. Copyright 2019, Optica publishing group.