Abstract
Deep ultraviolet (DUV) optical wireless communications have seen increased interest in recent years due to the unique properties of light in this spectral region. However, the reported DUV data rates remain significantly lower than comparable demonstrations at visible wavelengths due to lower modulation bandwidths and/or output power of the sources. Here, we present a wavelength division multiplexing demonstration using three UV micro-light-emitting diodes emitting at nominal peak wavelengths of 285, 317, and 375 nm, respectively, each with an emitting area of approximately 1369 μm 2 (equivalent to circular device pixels of diameter ∼ 40 μm ). Using orthogonal frequency division multiplexing, data rates of 4.17, 3.02, and 3.13 Gbps were achieved from the 285, 317, and 375 nm devices, respectively, for a combined data rate of 10.32 Gbps transmitted over a distance of 0.5 m.
Highlights
Optical wireless communication (OWC) has seen much attention as a possible solution to the predicted “data crunch” facing radio frequency (RF) communications [1,2]
This paper demonstrates wavelength division multiplexing (WDM) using three UV μLEDs with peak emission at 285, 317, and 375 nm, respectively
The decrease in signal-to-noise ratio (SNR) translated to an increase in the bit error rate (BER) and a decrease of the maximum data rate
Summary
Optical wireless communication (OWC) has seen much attention as a possible solution to the predicted “data crunch” facing radio frequency (RF) communications [1,2]. The relatively low output power of the UV-B device may be attributed to the relative lack of development of material at these wavelengths, as there is currently no high-volume application for LEDs emitting in this range [18]. This complicates the process of estimating the devices’ bandwidths. The further development of high-bandwidth UV/ DUV sensitive APDs is urgently needed to facilitate the full measurement of μLED devices such as those reported here Compared with their UV-A counterparts, the high modulation bandwidths and lower output power of the UV-B and -C devices. We speculate that the saturation and decrease of the bandwidth as seen in the UV-B and UV-C, respectively, may be attributed to device heating and thermally mediated effects such as carrier overflow reducing the carrier density in the quantum wells, increasing the average carrier lifetime and reducing the bandwidth [20]
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