盲辨识补偿的微波光子链路线性化技术  

Blind Identification and Compensation for Linearization of Microwave Photonic Links

作　　者：梅理 马少春 徐珍珠 韩守保 崇毓华 Mei Li;Ma Shaochun;Xu Zhenzhu;Han Shoubao;Chong Yuhua(The 38th Research Institute of China Electronics Technology Group Corporation,Hefei 230000,Anhui,China)

机构地区：[1]中国电子科技集团公司第三十八研究所,安徽合肥230000

出　　处：《光学学报》2024年第13期38-43,共6页Acta Optica Sinica

基　　金：安徽省重点研究与开发计划(2022a05020027,202104a05020052)。

摘　　要：针对微波光子链路非线性失真的盲辨识数字补偿问题,本文基于频谱功率门限对光链路输出信号进行非线性失真分量盲分离,并提出二次非线性拟合的数字补偿方法提升强非线性的微波光子链路交调失真抑制。通过高速示波器采集微波光子链路的输出信号并进行离线数字补偿处理,使用非线性阶数为5、记忆深度为16的记忆多项式模型对光链路非线性特性进行拟合和数字补偿,可实现2.6~16.8 GHz频段光链路的三阶交调抑制度提升20 dB以上。Objective In recent years, microwave photonic technology has caught extensive attention in electronic information equipment due to its low transmission loss, ultra-wideband, and high amplitude-phase consistency. Since Mach-Zehnder(MZ) modulators have inherent nonlinear characteristics, the electro-optic modulation of radio frequency(RF) signals will induce nonlinear distortions. For applications such as optical beamforming, optical analog-to-digital conversion, and optical frequency conversion which integrate electro-optic modulation into RF analog transceivers, the nonlinear distortion caused by electro-optic modulation will reduce the spurious-free dynamic range(SFDR) of RF transceivers. This in turn limits the application and advancement of microwave photonic technology. Thus, we address the nonlinear distortion in microwave photonic links with blind identification and digital compensation methods. By adopting these methods, the SFDR of microwave photonic links can be improved without modifying the original microwave photonic systems.Methods By converting the output of microwave photonic link into digital signals by the high-speed analog-to-digital converter, digital signal processing techniques that employ blind identification compensation can be utilized to suppress the link's nonlinear distortion(Fig. 2). The digital signal is first converted to an intermediate frequency(IF) signal via digital down-conversion, and then a memory polynomial model is leveraged to fit the nonlinear intermodulation distortions within the signal. This fitted distortion is subtracted from the original IF signal to achieve nonlinear distortion suppression. We propose employing a spectrum reduction algorithm based on time-frequency transformation to blindly identify the high power signal and distortions within the IF signal. The processing enables the parameter extraction for the memory polynomial model. The IF signal is first transformed into the frequency domain using the fast Fourier transform(FFT). By setting a power threshold i

关 键 词：微波光子学 数字线性化 交调失真 盲辨识补偿 

分 类 号：TN911.7[电子电信—通信与信息系统]