Zhu Zihang, Zhao Shanghong, Li Yongjun, Chu Xingchun, Hou Rui, Wang Xiang, Zhao Guhao
College of Information and Navigation, Xi’an 710077, China.
J Opt Soc Am A Opt Image Sci Vis. 2012 Dec 1;29(12):2525-31. doi: 10.1364/JOSAA.29.002525.
An exact analytical expression of the signal-to-noise ratio (SNR) for an intersatellite microwave photonics link with an optical preamplifier is derived considering the signal fade caused by the pointing errors of the transceiver, and an optimized model for laser output power and direct current (DC) bias phase shift of the Mach-Zehnder modulator is established. It is shown that, given the desired SNR and the root mean square (rms) random pointing jitter, an optimal DC bias phase shift exists that minimizes laser output power. The effects of the optical preamplifier parameters on the minimum laser output power and optimal DC bias phase shift are also examined. Numerical results show that the preamplifier noise figure determines the minimum laser output power needed to achieve the desired SNR but affects the optimal DC bias phase shift little. For a SNR of 20 dB, doubling the preamplifier noise figure results in a 6.36 dB increase in minimum laser output power for rms pointing jitter of 0.4 μrad.
考虑到收发器指向误差引起的信号衰落，推导了具有光前置放大器的星间微波光子链路信噪比（SNR）的精确解析表达式，并建立了马赫-曾德尔调制器激光输出功率和直流（DC）偏置相移的优化模型。结果表明，在给定所需信噪比和均方根（rms）随机指向抖动的情况下，存在一个使激光输出功率最小的最佳直流偏置相移。还研究了光前置放大器参数对最小激光输出功率和最佳直流偏置相移的影响。数值结果表明，前置放大器噪声系数决定了实现所需信噪比所需的最小激光输出功率，但对最佳直流偏置相移影响很小。对于20 dB的信噪比，当均方根指向抖动为0.4 μrad时，将前置放大器噪声系数加倍会导致最小激光输出功率增加6.36 dB。
