星上微波信号光学调制偏置点优化理论及仿真研究

Theoretical and simulated research on bias points optimization of optical modulation of microwave signals on board satellite

摘要: 研究了基于双电极马赫曾德尔干涉仪(DE-MZM)的星上微波信号光学调制方法,获得了单频段微波信号输入时的调制器输出光场表达式,推导了载噪比、射频增益、噪声系数及无杂散动态范围四个参数的解析表达式,建立了星上微波光子链路传输方程。利用OptiSystem仿真软件,搭建了单频段微波信号输入时的星上微波光子链路仿真系统,对链路性能进行了仿真研究。研究结果表明,调制器直流偏置点在正交点时,射频信号增益最高;直流偏置点在低偏置点时,载噪比、噪声系数和无杂散动态范围三个性能指标最优。

Abstract: Optical modulation theory of DE-MZM on board satellite was studied, output optics field expression of modulator with single input microwave signal was obtained. The analytical expression of four key parameters including carrier to noise ratio(CNR), RF gain, noise figure(NF), spurious-free dynamic range(SFDR) were deduced. The inter-satellite links transmission equation of microwave photonics was built. Using simulation software of OptiSystem, simulated model of microwave photonics links on board satellite was constructed and simulating research was performed. The simulated results show when the bias point is set to orthogonal bias point, RF gain is optimal. CNR, NF and SFDF are synchronously optimized when the modulator is low biased.