多频段多路信号同步调制时，星间微波光子链路性能与单路信号调制时相比有很大不同。基于Ku和Ka频段4路信号同步调制的星间微波光子链路模型，实现了卫星接收射频信号在光域上的放大、传输和分束等处理，利用贝塞尔函数展开分析了输出端非线性失真分量，推导了单边带、双边带和推挽调制方式下输出信号失真比(SDR)和信号噪声失真比(SNDR)。结果表明，非线性失真对单边带调制的影响小于双边带调制；单边带和双边带调制时最优输出SNDR值相同，对应的双边带调制时调制系数小于单边带调制；推挽调制方式时低偏置相位不能优化输出SNDR值。综合考虑输出信号质量和功耗因素，多频段信号同步调制时星间微波光子链路应选取双边带调制方式。

The performance of intersatellite microwave photonic link under synchronous modulation of multiple-frequency-band signals is different to the situation of single channel signal modulation. The link with synchronous modulation of four-channel signals of Ku and Ka bands is modeled. The radio-frequency signals received by satellite are optically processed such as amplification, transmission and distribution. The nonlinear components are analyzed with Bessel expansion, the signal-to-noise and distortion ratios (SNDRs) under single sideband (SSB), double-sideband (DSB) and push-pull modulation are derived. The link performances with different modulation are contrasted. The results show that, nonlinear distortion has a more serious effect on SSB modulation than DSB modulation. The optimal SNDR of SSB modulation is equal to that of DSB modulation and the corresponding modulation index of SSB is higher than that of DSB. Low bias of push-pull modulation cannot optimize the SNDR. Taking signal quality and power into consideration, the intersatellite microwave photonic link under synchronous modulation of multiple-frequency-band signals should choose the DSB modulation.