基于周期极化铌酸锂波导的软件同步光采样

随着大于40 Gb/s高速光通信系统的出现, 为了保证光信号传输质量, 需要对光信号进行监测。对于带宽超过传统光电探测器和示波器可测量带宽的高比特率数据光信号, 光采样技术是进行时域测量的重要手段。采用固定频差的方法可以用百兆速率的采样脉冲对高速光信号进行采样, 降低了对采样后电数据处理系统带宽的要求。在对基于周期极化铌酸锂(PPLN)波导中和频效应的采样过程进行建模仿真的基础上, 实现了对Optsim获得的光传输线内10 Gb/s的非归零码(NRZ)和归零码(RZ)信号的采样。采用软件同步算法对采样数据进行处理, 获得信号的眼图, 这一方法可使采样系统对硬件的要求降到最低。与理想与门获得的采样结果进行比较, 对PPLN波导的光采样特性和采样质量进行了分析。

Software-Synchronized Optical Sampling Based on PPLN Waveguide

With the emergence of high speed optical communication system above 40 Gb/s, to ensure the quality of the transmitted optical signal, the optical signal in the transmission line should be monitored. The optical sampling technique is an important tool to perform time-resolved measurements of optical data signals at high bit rates with a bandwidth that cannot be reached by conventional photodetectors and oscilloscopes. The method with a fixed offset frequency can be used to sample the high speed optical signals with the sampling pulses of several hundred MHz. It relaxes the requirements of the bandwidth of electrical data processing system after the sampling. Based on the modeling and simulation of optical sampling process utilizing the sum-frequency generation in periodically poled lithium niobate (PPLN), the optical sampling of 10 Gb/s nonreture-to-zero (NRZ) and retrun-to-zero (RZ) signals in the transmission line obtained by Optsim is realized. The sampling results are processed by software-synchronized algorithm and the eye diagram of the signals is constructed. This method requires the least amount of hardware components. Compared with the sampling results of ideal AND gate, the sampling characteristics of PPLN waveguide and the quality of the sampling are analyzed by the obtained eye diagrams.