Miniaturized light sources at telecommunication wavelengths are essential components for on-chip optical communication systems. Here, we report the growth and fabrication of highly uniform p-i-n core-shell InGaAs/InP single quantum well (QW) nanowire array light emitting diodes (LEDs) with multi-wavelength and high-speed operations. Two-dimensional cathodoluminescence mapping reveals that axial and radial QWs in the nanowire structure contribute to strong emission at the wavelength of ~1.35 and ~1.55 μm, respectively, ideal for low-loss optical communications. As a result of simultaneous contributions from both axial and radial QWs, broadband electroluminescence emission with a linewidth of 286 nm is achieved with a peak power of ~17 μW. A large spectral blueshift is observed with the increase of applied bias, which is ascribed to the band-filling effect based on device simulation, and enables voltage tunable multi-wavelength operation at the telecommunication wavelength range. Multi-wavelength operation is also achieved by fabricating nanowire array LEDs with different pitch sizes on the same substrate, leading to QW formation with different emission wavelengths. Furthermore, high-speed GHz-level modulation and small pixel size LED are demonstrated, showing the promise for ultrafast operation and ultracompact integration. The voltage and pitch size controlled multi-wavelength high-speed nanowire array LED presents a compact and efficient scheme for developing high-performance nanoscale light sources for future optical communication applications.

Although the 5G wireless network has made significant advances, it is not enough to accommodate the rapidly rising requirement for broader bandwidth in post-5G and 6G eras. As a result, emerging technologies in higher frequencies including visible light communication (VLC), are becoming a hot topic. In particular, LED-based VLC is foreseen as a key enabler for achieving data rates at the Tb/s level in indoor scenarios using multi-color LED arrays with wavelength division multiplexing (WDM) technology. This paper proposes an optimized multi-color LED array chip for high-speed VLC systems. Its long-wavelength GaN-based LED units are remarkably enhanced by V-pit structure in their efficiency, especially in the “yellow gap” region, and it achieves significant improvement in data rate compared with earlier research. This work investigates the V-pit structure and tries to provide insight by introducing a new equivalent circuit model, which provides an explanation of the simulation and experiment results. In the final test using a laboratory communication system, the data rates of eight channels from short to long wavelength are 3.91 Gb/s, 3.77 Gb/s, 3.67 Gb/s, 4.40 Gb/s, 3.78 Gb/s, 3.18 Gb/s, 4.31 Gb/s, and 4.35 Gb/s (31.38 Gb/s in total), with advanced digital signal processing (DSP) techniques including digital equalization technique and bit-power loading discrete multitone (DMT) modulation format.