一种具有高交调抑制比的倍频信号产生及模拟信号传输方法

An approach for double-frequency signals generation and analogue transmission with high inter-modulation distortion suppression

基于DPMZM和两个电移相器，文中给出了一种具有高交调抑制比的倍频信号产生及模拟信号传输方法，该方法可广泛应用于ROF系统中。通过调整DPMZM的直流偏置工作点和电移相器相位，可生成高交调失真抑制比的倍频信号。基于同一结构，仅调整DPMZM中一个子调制器的直流工作点就可以实现高线性模拟信号传输。实验结果表明，所生成的倍频信号的交调失真比可达30dB以上；所构建的高线性模拟信号传输链路可完全抑制三阶交调失真分量。该方法在降低ROF系统难度和复杂度的同时，大大提高了系统稳定性。实验结果与理论分析结果相吻合。

An approach of double-frequency signal generation and analogue transmission with high intermodulation distortion suppression was described, which can be widely used for Radio Over Fiber（ROF） system. The approach was mainly based on a Dual-Parallel Mach-Zehnder modulator （DPMZM） and two electrical phase shifters. By adjusting the three biases of the DPMZM, double-frequency signals with high inter-modulation distortion suppression were generated. On the same structure, by adjusting bias of MZM2, which is the sub-modulator of DPMZM, and controlling the electrical drive voltages on the electrodes of MZM2, an analog photonic link with high IMD3 （third-order inter-modulation distortion） suppression was realized. From tests, the double-frequency signals with inter-modulation distortion suppression of approximately 30 dB and the analog photonic link with complete IMD3 suppression were validated and proved. The approach reduces the difficulty, complexity, and costs of ROF system, while increasing the stability of ROF system. Experimental results for IMD3 suppression are well matched with the analysis ones.