带前置光放大的星间微波光子链路性能优化  

Optimization of optically pre-amplified inter-satellite microwave photonic links

作　　者：朱子行[1] 赵尚弘[1] 李勇军[1] 楚兴春[1] 张辉[2] 王翔[1] 赵顾颢[1] 

机构地区：[1]空军工程大学信息与导航学院,陕西西安710077 [2]空军工程大学,陕西西安710051

出　　处：《光电子．激光》2013年第3期500-507,共8页Journal of Optoelectronics·Laser

基　　金：国家"863"计划(2007AA01Z294);国家自然基金(61108068)资助项目

摘　　要：考虑发射机和接收机对准误差引起的信号衰落,推导出带前置光放大的星间微波光子链路输出信噪比(SNR)的解析表达式,并建立了基于平均SNR原则的链路优化模型。在给定SNR要求及对准误差条件下,对Mach-Zehnder调制器(MZM)直流偏置相移进行了优化,使所需激光器(LD)输出功率最小,并进一步分析了前置放大器参数对最小LD输出功率和最优直流偏置相移的影响。数值仿真结果表明,与增益相比,前置放大器噪声系数决定了指定SNR所需的最小LD输出功率。当对准误差角标准差为0.4μrad时,噪声系数加倍会使SNR达到15.56dB时所需的最小LD输出功率增加6.73dB。然而,前置放大器噪声系数对最优的直流偏置相移几乎无影响,噪声系数加倍后最优直流偏置相移的变化不会超过0.003π。The analytical expression of output signal-to-noise ratio （SNR） for inter-satellite microwave photonic links with an optical preamplifier is derived considering the signal fade caused by both transmitter＇s and receiver＇s pointing errors, and an optimized model for the average SNR is established. With the desired SNR and the pointing errors of transmitter and receiver,the direct current （DC） bias phase shift of Mach-Zehnder modulator （MZM） can be optimized so as to minimize the output power of laser diode （LD）,and the effects of the optical pre-amplifier parameters on the minimum output power of LD and optimal I）C bias phase shift are also examined. According to the numerical results,the preamplifier noise figure determines the minimum output power of LD needed to achieve the desired SNR. The required minimum output power of LD to maintain the SNR of 15.56 dB increases by 6.73 dB for an RMS pointing jitter of 0. 4 μrad when doubling the preamplifier noise figure. In contrast, the preamplifier noise figure has little influence on the optimal IX; bias phase shift, doubling the pre-amplifier noise fig ure,resulting in no more than 0. 003π increase in the optimum DC bias phase shift.

关 键 词：星间微波光子链路 前置光放大器 信噪比(SNR) 对准误差 

分 类 号：TN927.2[电子电信—通信与信息系统]