通道内幅度噪声和通道间幅度不匹配是限制时间波长交织光模数转换系统(TWIPADC)性能的主要因素。提出了一种基于自适应干扰对消的TWIPADC幅度校正方法。该方法采用自适应干扰对消原理实时消除光源抖动和光时分复用模块引入的通道内幅度噪声,同时采用基于标定的方案对波分复用(WDM)模块等引入的通道间幅度不匹配进行校正。给出了基于所提幅度校正方案的TWIPADC系统结构,通过建立相应的数学模型,理论分析了所提幅度校正方案的原理和流程。仿真结果表明:基于自适应对消理论,可以有效实时消除TWIPADC中光源以及OTDM模块引入的幅度噪声;所提幅度校正方案可以将16通道、32GS/s TWIPADC系统的信纳比提升30dB以上。
In-channel amplitude noise and inter-channel amplitude mismatch are main factors limiting the performance of time-wavelength interleaved photonic analog-to-digital conversion(TWIPADC)system. An amplitude correction method based on adaptive noise cancellation principle for TWIPADC is proposed.In the scheme,the in-channel amplitude noise introduced by unstability of the laser source and optical time division multiplexing(OTDM)module is eliminated in real time by using the adaptive interference cancellation principle,while the inter-channel amplitude mismatch introduced by the wavelength division multiplexing module is corrected by adopting a calibration procedure.The structure of TWIPADC system based on the proposed correction scheme is presented.The proposed amplitude correction principle and procedure are analyzed theoretically by building the corresponding mathematical model.The simulation results show that the amplitude noise of TWIPADC caused by optical source and OTDM module can be eliminated in real time effectively by the proposed adaptive cancellation scheme.The signal-to-noise-and-distortion ratio of a 32GS/s TWIPADC system with 16-channel can be improved more than 30 dB by using the proposed amplitude correction method.