Single-Photon Ultraviolet-C Communication Enabled by SiPM Photon-Counting Within PPM Time Slots

Short-wave ultraviolet (UV-C) band communication features extremely low background noise and invisibility. However, intense Rayleigh scattering caused by its shorter wavelength leads to rapid attenuation of light intensity down to the single-photon level. In this Letter, a 275 nm UV-C link is established using pulse position modulation (PPM) and a silicon photomultiplier (SiPM) is reported. The transmitter employs a compact field-programmable gate array (FPGA) and implements PPM and coding. The receiver simultaneously captures both the PPM signal and the response signal from the SiPM to the arriving photon sequence via an oscilloscope. By analyzing the photon count statistics within the PPM time slots, we estimate the bit error rate (BER) of the UV-C link employing this single-photon counting scheme. In addition, the effect of PPM time slot width variation on the BER performance is also investigated. This work provides a reference for the realization of the real-time prototype of the extremely weak single-photon link system based on FPGA.