研究了一种基于高非线性光纤(HNLF)中交叉相位调制效应的全光频率上转换射频耦合到光纤无线通信(ROF)系统。数值计算结果表明, 由于交叉相位调制引起的调制不稳定性, 波长1.54 μm, 重复频率为40 GHz的抽运光可使波长为1.56 μm, 载有速率为2.5 Gbit/s的非归零码作为下行链路数据的弱信号光光波分裂, 产生与载波距离为40 GHz且与载波相干的两个一阶调制边带, 抽运光脉宽、抽运光功率和光纤长度对载波与边带功率差有较大影响。仿真实验结果证实了以上原理, 速率为2.5 Gbit/s的数据信号在高非线性光纤中被上转换到40 GHz毫米波上。信号光功率为0 dBm时, 得到的优化光纤长度为600 m, 抽运光功率为17 dBm。

All-optical frequency up-conversion in radio over fiber (ROF) system based on cross-phase modulation in a high nonlinear fiber is proposed. The numerical calculation results show that the 40-GHz pulse pump beam with wavelength of 1.54 μm can make the weak signal with wavelength of 1.56 μm and nonreturn to zero code velocity of 2.5 Gbit/s split and generate two adjacent one-order sidebands, because of the modulation instability induced by cross-phase modulation. The carrier and sidebands are coherent with the spacing of 40 GHz. The pulse width, power of the pump beam, and fiber length all have great impact on the power difference of the carrier and sidebands. The simulation results verify the above principle and 2.5-Gbit/s data signal is up-converted into 40-GHz millimeter-wave in high nonlinear fiber. The optimized fiber length and pump power are 600 m and 17 dBm, respectively, when the power of the signal light is 0 dBm.