光DPSK调制系统眼图交叉点控制技术

Eye diagram crossing-point control technology in optical DPSK modulation system

针对光相位调制过程中光调制器受外界影响及输入信号不稳定等因素引起的眼图交叉点上下浮动现象,采用自适应控制方案实现眼图交叉点电压实时控制,通过过零点电平中数控直流电平的改变实现调制信号交叉点的校正,解决眼图交叉点漂移。实验结果表明:输出眼图交叉百分比有明显改善,偏移误差减小,眼图张开效果较好,能有效稳定输出信号。最后验证了方案设计的可行性。

For the optical phase modulation process,the phenomenon of eye diagram cross-point floating occurs because of the optical modulator affected by external influences and the instability of the input signal.The real-time control of the eye crossing-point voltage through the zero-crossing level has realized by an adaptive control scheme.And with the digital control DC level of the zero level circuit changed,the correction of the crossing point of the modulated signals and fluctuation of the eye crossing point has solved.It is verified by experiments that the output percentage of the crossing-point of the eye diagram is obviously improved and the offset error was reduced,the opening effect of eye diagram is better and the output signal is effectively stabilized.Finally,the feasibility of the scheme design is verified.