基于调制边带法的高次倍频光毫米波产生

Multiple frequency optical millimeter wave generation based on modulation sideband technique

提出了利用外调制技术的调制边带法的六倍频和八倍频光毫米波产生方案。方案仅采用一个马赫曾德尔调制器,并利用其非线性传输特性,通过调节MZM的偏置电压和调制电压,控制边带的强度,仅保留三阶边带或四阶边带,从而实现六倍频及八倍频光毫米波的产生。采用将基带数据信号仅调制在一个三阶边带或四阶边带分量的方式,有效防止走离。数值分析结果表明,提出的方案仅需10 GHz及7.5 GHz的调制信号频率就能得到60 GHz毫米波,大大减小了调制信号频率,增加了上变频系数,传输距离可达160 km,而功率代价变化不大。与提出的其他高倍频技术相比,由于系统仅采用一个马赫曾德尔调制器,提出的方案系统结构更为简单,且此方案色散影响较小,传输距离更长。

A novel scheme was proposed to generate sextupling-frequency and octupling-frequency optical millimeter wave by using external modulator technique. Based on the nonlinear transmission characteristics of one Mach-Zehnder modulator（MZM）, the third-order or fourth-order sideband could be enhanced by adjusting the bias voltage and the modulation voltage of MZM, and thus generated successfully sextupling-frequency or octupling-frequency optical millimeter wave. Walk-off effect could be prevented by only modulating the signal on one of the third-order or fourth-order sidebands. Numerical results demonstrate that the proposed scheme generate 60 GHz millimeter wave with only 10 GHz and 7.5 GHz frequency modulated signal, which greatly reduces the frequency of the modulation signal, increases the up-conversion coefficient, and reaches the transmission distance to 160 km without increasing the power penalty distinctly. Compared with other multiple frequency techniques, the proposed system has distinct advantages of simple configuration, low dispersion effect, long transmission distance due to only using one Mach-Zehnder modulator.