Structurally integrated transmitter beacon for underwater wireless optical communications in multiple ocean types

In this paper we describe a structurally integrated optical transmitter beacon concept that consists of a side-scattering fiber that can conform to solid surfaces, such as the outer surface of a submersible Remotely Operated Vehicle (ROV), suitable for convenient deployment in underwater applications. By coupling a modulated optical signal from a laser diode into the fiber, an omnidirectional "beacon" is achieved. We demonstrate coarse Wavelength Division Multiplexing (WDM), illustrating that these beacons can transmit optical wireless data through several attenuation lengths in turbid water at aggregate data rates of up to 20 Mb/s

Active-matrix GaN micro light-emitting diode display with unprecedented brightness

Displays based on microsized gallium nitride light-emitting diodes possess extraordinary brightness. It is demonstrated here both theoretically and experimentally that the layout of the n-contact in these devices is important for the best device performance. We highlight, in particular, the significance of a nonthermal increase of differential resistance upon multipixel operation. These findings underpin the realization of a blue microdisplay with a luminance of 10⁶ cd/m²

Effects of LED device size on UV-C short-range LoS optical wireless communication

We report systematic investigation of the device-size-dependent performance of ultraviolet C (UV-C) light emitting diodes (LEDs) for optical wireless communication (OWC). Utilizing 273 nm-wavelength devices with diameters in the range of 40 μ m to 300 μ m, the size-dependent electrical, optical and frequency response characteristics of AlGaN UV-C LEDs are analyzed. As the junction area scales down, the smaller devices present lower optical power but faster modulation speed. Based on a 1-m point-to-point OWC system, this study further explores the LED size effect on the communication performance including channel gain, signal-to-noise ratio (SNR), theoretical Shannon capacity, achievable data transmission rate, relevant ratio, and spectral efficiency (SE). The system employing a 60 μ m diameter (micro) LED transmitter achieves the highest average SNR and SE accompanying a data transmission rate up to a 5.53 Gbps at the forward error correction floor of 3.8 ×10−3 . These results suggest an optimal device diameter of ∼ 60 μ m for further development of high-performance UV-C short-range line-of-sight (LoS) OWC

Deep ultraviolet CMOS-controlled micro light-emitting diode array

We report a Deep Ultraviolet (DUV) AlGaN micro-light emitting diode (micro-LED) array driven by a matching array of electronic drivers implemented in Complementary Metal-Oxide-Semiconductor (CMOS) technology. This 40 × 10 pixel integrated device required improvements in micro-LED fabrication combined with control over the LED ground level in the custom designed CMOS chip. It allows each of the micro-LEDs, with a measured peak emission wavelength of 271 nm, to be addressed independently in continuous wave (CW) or nanosecond pulsed operation, with optical output powers and pulse energies per pixel of 80 μW and 0.2 pJ, respectively. Performance of this high-resolution electronically-driven array for multi-channel UV-C wireless communications is given as an example of its potentially wide-ranging uses

High-speed optical camera communication using CMOS-driven micro-LED projector

We demonstrate a 7.76-Mb/s optical camera communication system using a CMOS-driven micro-LED projector and a high-speed camera. PAM4 signal was transmitted based on the imaging multiple-input-multiple-output system. The results predict a potential data rate of over 1 Gb/s using the full micro-LED projector chip

Excitation of semiconductor nanowires using individually addressable micro-LED arrays

Optical pumping of nanowire emitters, embedded in polymeric waveguides is achieved using a micro-LED array at 410 nm. The micro-LED-on-CMOS chip allows for individual pixel control and therefore parallel pumping of multiple emitters simultaneously. The nanowires are integrated on-chip using high-accuracy transfer-printing and laser lithography

Hundred-meter Gb/s deep ultraviolet wireless communications using AlGaN micro-LEDs

We demonstrate the use of deep ultraviolet (DUV) micro-LEDs for long-distance line-of-sight optical wireless communications. With a single 285nm-emitting micro-LED, we have respectively achieved data rates greater than 6.5 Gb/s at a distance of 10m and 4 Gb/s at 60m. Moreover, we obtained >1Gb/s data rates at a distance of 116 m. To our knowledge, these results are the highest data rates at such distances thus far reported using deep DUV micro-LEDs and the first demonstration of Gb/s communication at >100m using any micro-LED-based transmitter

Scalable optical excitation and modulation of semiconductor nanowire emitters

We show that individually addressable micro-LED-on-CMOS arrays can be used as scalable optical excitation sources for arrayed semiconductor nanowire devices. This approach is used to demonstrate optical modulation at MHz rates of heterogeneously integrated nanowire-emitters

GaN-based series hybrid LED array : a dual-function light source with illumination and high-speed visible light communication capabilities

We propose and demonstrate a GaN-based series-driven hybrid light emitting diode (SH-LED) device in which broad-area and micro-LED components are interconnected for simultaneous illumination and high-speed visible light communication (VLC) applications. Through theoretical analysis based on an equivalent electrical circuit model and characterization from a fabricated exemplar device with blue emission, it is shown that SH-LEDs combine the advantages of broad- and micro-LED components by offering high direct-current (DC) optical power output and a fast frequency response. The application of this device to VLC is demonstrated through both the point-to-point and 9o divergence-angle coverage systems at 3 m transmission distance adopting a DC-biased optical-orthogonal frequency-division multiplexing modulation scheme. Compared with a point-to-point system using a single micro-LED, the one employing an SH-LED achieves the same data transmission rate of 3.39 Gbps at forward error correction (FEC) floor of 3.8×10-3, but the received DC optical power is improved by over 3 times. For the area coverage system, up to 1.56 Gbps data transmission rates at a FEC floor of 3.8×10-3 are accomplished by using this device, associated with over 4 times higher received DC optical power compared with the one using a single micro-LED