中心博士生王鑫的工作——Power-Independent Microwave Instantaneous Frequency Measurement Based on Combination of Brillouin Gain and Loss Spectra（基于布里渊增益损耗谱的功率无关微波瞬时频率测量）的相关成果近期被IEEE Photonics Journal期刊接收发表，该工作得到了国家重点研发计划（2019YFB2203700）、国家自然科学基金（61822508）的部分资助。光子辅助微波瞬时测频(IFM)具有测频范围宽、处理速度快等优点，是一种很有前途的未知射频信号检测技术。到目前为止，还没有一种能从本质上测量功率波动严重的未知射频信号时频信息的光子辅助IFM系统。此外，测量精度和频率调制识别也不如传统的电子方法。本文提出了一种基于布里渊增益谱(BGS)和布里渊损耗谱(BLS)相结合的IFM方案，该方案不依赖射频功率，测量效率高。将BGS与BLS相结合构建幅值比较函数(ACF)，可通过单次测量减小21.27 dB范围内射频信号功率波动的影响。当在泵浦光波上调制一个具有微波梳状信号频域单调功率的适当频率区间时，未知信号的IFM精度可达1 MHz左右。系统经过初始校准后，能够识别单音信号、线性调频信号、非线性调频信号和Costas信号的时频变化。该方案将有助于促进IFM在频谱侦察与接收领域的应用。
摘要:Photonics-assisted microwave instantaneous frequency measurement (IFM) is considered as a promising technique for detecting an unknown radio-frequency (RF) signal, which has advantages of broad frequency measurement range and fast processing speed. Up to date, there is no photonics-assisted IFM system that can essentially measure an unknown RF signal time-frequency information with power fluctuating seriously. Moreover, the measurement accuracy and frequency modulation recognition are not as good as those of traditional electronic methods. Here, we propose an IFM scheme based on the combination of Brillouin gain spectrum (BGS) and Brillouin loss spectrum (BLS), which is RF-power-independent with high measurement efficiency. The combination of BGS and BLS to construct the amplitude comparison function (ACF) can reduce the influence of RF signal power fluctuation within 21.27 dB by single-shot measuring. When an appropriate frequency interval with frequency domain monotonous power of microwave comb signal is modulated on the pump lightwave, the IFM accuracy of the unknown signal reaches about 1 MHz. After the initial calibration of the system, it can recognize the time-frequency variation of single tone signal, linear frequency modulated signal (LFM), nonlinear frequency modulated signal (NLFM), and Costas signal. This scheme will help to promote the application of the IFM in the field of spectrum reconnaissance and reception.