A compact signal transmitter for UV communication system

Abstract

Three LED-based signal transmitting schemes were presented to build the transmitter of UV communication system. Microprogrammed Control Unit (MCU) was taken to generate digital driving signal and to accomplish modulation with Keil C51 development tool. The modulated signal with a certain pulse width was sent to a LED driving circuit. High power 365nm UV LED was adopted according to the trade-off between its scattering coefficient and price. Utilization of high power UV LED improved the integration density of printed circuit board (PCB), which was beneficial to assemble a beam shaping system. The whole transmitter was installed on a four-dimensional optical stage for system adjustments and measurements. The radiant optical power of UV LED was measured. Some issues about the PCB design were also discussed. The MCU output waveforms were demonstrated on an oscilloscope and the UV LED output optical pulse were verified by a Hamamatsu APD module. Different modulation data rates were investigated. Experimental result showed that this signal transmitter for UV communication system could transmit optical signal well and greatly shorten the system development cycle.