Electro-Optic Modulators: On-Chip Dual Electro-Optic and Optoelectric Modulation Based on ZnO Nanowire-Coated Photonic Crystal Nanocavity (Advanced Optical Materials 17/2018)

Electronic–photonic hybrid integrated circuits represent the essential basis of next‐generation ultrahigh‐speed information processing chips, which will require ultrafast and ultralow‐energy‐consumption electronic and photonic information interconversion and modulation, i.e., on‐chip dual electro‐optic and optoelectric modulation. However, this type of modulation has not been realized to date because of an absence of materials that demonstrate sufficient intrinsic electro‐optic and optoelectric responses simultaneously. On‐chip dual electro‐optic and optoelectric modulation is experimentally realized here based on refractive index variation of a ZnO nanowire driven by the gate voltage and electrical conductivity changes in this nanowire caused by the strong localized light field of a silicon nitride photonic crystal nanocavity mode. A low gate voltage of 1.5 V induces a large shift of 7 nm in the Fano‐like resonance wavelength and modulates the propagation state of an 800 nm light signal with a large modulation depth of 75%. Additionally, weak signal light with power as low as 0.4 µW induces a modulation depth of 60% in the electric signal. On‐chip conversion between electronic and photonic signals thus is achieved. This work paves the way toward realization of novel nanoscale multifunctional optoelectronic integrated devices and provides an on‐chip platform for the study of new optoelectronic functional materials.