星上双频段多通道微波光子链路传输性能的优化研究  

Performance optimization of the microwave photonic link on board with dual-frequency bands and multi-channel

作　　者：李勇军[1] 李轩[1] 缪新萍[1] 朱子行[1] 

机构地区：[1]空军工程大学信息与导航学院,陕西西安710077

出　　处：《光电子．激光》2015年第9期1685-1691,共7页Journal of Optoelectronics·Laser

基　　金：国家自然科学基金(61231012);陕西省自然科学基础研究计划(2015JM6360)资助项目

摘　　要：利用星上微波光子技术,将多个频段微波信号调制到光域,可解决数据在星上的高速处理和星间远距离传输等问题。当多频段微波信号进行光学调制时,交调失真是影响星上多频段微波信号光域传输性能的重要因素。研究了星上双频段、每个频段内2信道的微波信号光学调制方法,分别推导了Ku、Ka波段微波信号的输出信号噪声失真比(SNDR)和无杂散动态范围(SFDR)表达式,分析了各次谐波和各阶交调失真分量对链路性能的影响,获得了保证链路输出SNDR最优的最佳直流偏置相位和调制系数。利用OptiSystem软件建立了仿真模型,并进行了仿真验证。研究结果表明,Ku频段中非线性交调分量包括自频段三阶交调(IMD3)分量、频段间IMD3分量和频段间二阶交调(IMD2)分量;Ka频段中非线性交调分量包括自频段IMD3分量、Ku频段IMD2分量、Ku频段二次谐波(HD2)分量以及频段间IMD3分量。对于Ku频段信号,当调制系数和直流偏置相位分别为0.17和0.535π时,SNDR取得最优值21.50dB;对于Ka频段信号,调制系数和直流偏置相位分别为0.22和0.525π时,SNDR取得最优值15.32dB。Multiple frequency microwave signals can be modulated into optical field simultaneously with microwave photonic technology on board satellite. Therefore data may be processed at high speed on- board and transmitted over long distances between two satellites. When multi-frequency band microwave signals are modulated, the inter-modulation distortion is one of the important factors which affect the op- tical transmission performance of multiple frequency bands microwave signals. The Optical modulating method of on board dual-frequency bands microwave signals with two channels in each frequency band is researched. Several orders of harmonies and inter-modulation distortion terms are analyzed. Expressions of output signal to noise distortion ratio （SNDR） are deduced. Optimized DC bias phase and modulation index are calculated, which guarantee the optimized output SNDR. Simulated models are built up based on simulated software of OptiSystem. Research results show that nonlinear inter-modulation products of Ku include the third-order inter-modulation distortion （IMD3） of Ku,IMD3 and the second-order inter- modulation distortion （IMD2） between two frequency bands ; Nonlinear inter-modulation products of Ka include IMD3 of Ka,IMD2 of Ku,the second harmonic distortion （HD2） of Ku and IMD3 between two frequency bands. Simulated results show that when modulation index is 0. 17,DC bias phase is 0. 535n, and optimized SNDR of Ku frequency band is 21.50 dB. When modulation index is 0.22,DC bias phase is 0. 525n,and optimized SNDR of Ka frequency band is 15.32 dB.

关 键 词：星上处理 微波光子 多频段微波信号 信号噪声失真比 

分 类 号：TN927.2[电子电信—通信与信息系统]