On‐Chip Dual Electro‐Optic and Optoelectric Modulation Based on ZnO Nanowire‐Coated Photonic Crystal Nanocavity

Abstract

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.

Nanowires for Photonics

“…(c) Optical images of the ZnO nanowire coupled photonic crystal as an optical modulator. Adapted with permission from ref . Copyright 2018 John Wiley and Sons.…”

“…Figure b is an optical image of InP-based optical polarization rotator-splitter . An optically coupled ZnO nanowire and photonic crystal as an optical modulator is shown in Figure c . Although these attempts can demonstrate a possibility of the nanowire-based auxiliary optical components, a high-resolution, spatially precise, and scalable demonstration for on-chip integrations of each component should be achieved to take full advantage of nanowire-based optical components for circuit integration.…”

Nanophotonic Polarization Routers Based on an Intelligent Algorithm

“…Figure 5f,g show the normalized transmission spectra at the output ports O1 and O2, and the maximum normalized transmittances of output ports O1 and O2 are 81% and 85%, respectively. The normalized transmittances is the ratio of the measured intensity of patterned sample to the unpatterned sample, [ 43,44 ] and the process of calculation is shown in Section S4 in the Supporting Information. Due to the imperfect fabrication of FIB etching technique, the corner of some rectangle hole is fillet, and the diameter of the holes decreases as the etched depth increases.…”

Nanowire-assisted microcavity in a photonic crystal waveguide and the enabled high-efficiency optical frequency conversions

“…With a further consideration of the much larger refractive indices of semiconductor NWs compared to the air, it is a challenge to launch light into NWs with an acceptable efficiency. To assist light-matter couplings in NWs, various photonic strategies have been utilized, including hybrid NWs with plasmonic structures [10][11][12][13], directly contacting NWs with microfiber for end couplings [14,15], and aligning NWs with on-chip waveguides and resonators [16][17][18][19]. Another viewpoint for future applications of NW devices is their integratability, which is very important in miniaturized and integrated systems.…”