设计了基于调制相移法的色散测量样机,提高了色散测量的精度,降低了色散测量成本。设计了基于幅相检测芯片AD8302的双鉴相电路,实现了相位差的准确测量。应用最小二乘法对接收的数据进行拟合,得到了可靠的色散系数曲线。整体采用模块化的设计思想,使用基于芯片F2812的数字信号处理,实现了对各模块插板的控制,完成了数据的采集和处理,并在实验室虚拟仪器工程工作台(LabVIEW)开发平台完成界面设计。对样机的性能进行了实验验证,结果表明,对于不同长度的G.652光纤,在波长1550 nm处,累积色散测量的不确定度小于10 ps/nm。

A dispersion measurement prototype is designed based on the modulation phase shift method, which improves the accuracy and reduces the cost of dispersion measurement. In addition, the dual phase discrimination circuit is designed based on the amplitude and phase detection chip AD8302 and the accurate measurement of phase difference is realized. The least square method is used to fit the received data and a reliable dispersion coefficient curve is obtained. The modular design is adopted as a whole. The digital signal processing based on chip F2812 is also used to accomplish the control to the board of each module as well as the collection and processing of data. The interface is designed on the LabVIEW development platform. The performance of the prototype is verified by experiments and the results show that the uncertainty of the cumulative dispersion measurement at wavelength of 1550 nm is less than 10 ps/nm for the G.652 fibers with different lengths.