大功率LED的发光瞬态响应及光调制

Luminous transient response and optical modulation of high power LED

为实现LED无线光通信大范围、远距离、高速率的传输,研究了大功率LED载流子注入与复合对光电响应速度的影响,设计了在FPGA控制下的载流子加速注入/抽出调制方案。通过在驱动电压脉冲上升沿施加一个瞬时过压和下降沿,将驱动输出端下拉或反偏,加速光脉冲的上升/下降沿,以避免光脉冲重叠所造成的码间干扰。测试结果表明,大电流调制可提高大功率LED的光信号质量和传输速率。

To achieve a wide range or long distance of the LED-based wireless communication, the power LED carrier injec- tion and recombination process and their influence on optical-electric response in the pulse drive are investigated. The modu lation technique is designed by accelerating carrier injection/extraction in the control of FPGA. A transient over voltage is applied to the rising edge of the driving pulse and a pull down or reverse bias is set at the falling edge. The rising/falling ed- ges are speeded up for avoiding the intersymbol interference. The measurement results show that the optical signal quality under the large current of modulation is significantly improved, and the transmission rate can be effectively promoted.