1 Gbps free-space deep-ultraviolet communications based on III-nitride micro-LEDs emitting at 262 nm

The low modulation bandwidth of deep-ultraviolet (UV) light sources is considered as the main reason limiting the data transmission rate of deep-UV communications. Here, we present high-bandwidth III-nitride microlight-emitting diodes (mu LEDs) emitting in the UV-C region and their applications in deep-UV communication systems. The fabricated UV-C mu LEDs with 566 mu m(2) emission area produce an optical power of 196 mu W at the 3400 A/cm(2) current density. The measured 3 dB modulation bandwidth of these mu LEDs initially increases linearly with the driving current density and then saturates as 438 MHz at a current density of 71 A/cm(2), which is limited by the cutoff frequency of the commercial avalanche photodiode used for the measurement. A deep-UV communication system is further demonstrated. By using the UV-C mu LED, up to 800 Mbps and 1.1 Gbps data transmission rates at bit error ratio of 3.8 x 10(-3) are achieved assuming on-off keying and orthogonal frequency-division multiplexing modulation schemes, respectively. Published by Chinese Laser Press under the terms of the Creative Commons Attribution 4.0 License.