提出了一种利用分布反馈DFB(Distributed Feedback laser)激光器的非线性对射频光传输系统动态范围进行优化的方案。实验研究了半导体分布反馈激光器的非线性,基于实验结果分析了DFB激光器的偏置电流与线性性能的关系。在此基础上建立了对马赫曾德外调制(Mach-Zehnder modulator,MZM)射频光传输系统线性优化方案。实验结果表明,该实验系统有效抑制了系统三阶交调量,系统的动态范围得到改善,当输入射频信号中心频率4 GHz,双音号间隔10 kHz时,三阶交调失真抑制23.1 dB,无杂散动态范围提高8.68 dB。

A scheme of dynamic range optimization for Microwave Photonic Link with Distributed Feedback laser(DFB) was proposed. The nonlinearity of the laser was experimentally studied. The relationship between the bias current and the linear performance of the DFB laser was analyzed experimentally. Based on the experimental results, the linear system of Mach-Zehnder modulator(MZM) system was established. The experimental results show that the third order intermodulation of the system is suppressed, when the center frequency of the input frequency signal is 4 GHz and two tone separation is 10 kHz, the three order distortion is suppressed 23.1 dB and the spurious-free dynamic range can be improved by 8.68 dB.