数值模拟了一种利用高非线性光纤(HNLF)中的交叉相位调制(XPM)效应实现归零(RZ)码到非归零(NRZ)码的转换方案，讨论了RZ信号的占空比对转换后NRZ码性能的影响。转换后NRZ码的性能受输入RZ信号占空比的影响，当RZ信号占空比在30%~50%范围内可实现较好地转换。同时，实验实现了码率为10 Gb/s、占空比为33%的 RZ码到NRZ码的转换，对比了连续探测光的原始谱和展宽谱，给出了转换前后信号的典型眼图和误码率(BER)特性。结果显示，在误码率为10-9时，由RZ码转换到NRZ码引入的功率代价不到1 dB。进一步的实验验证了这种方案在大于160 Gb/s或更高码率下的可行性。

All-optical RZ to NRZ format conversion based on cross-phase modulation in the high-nonlinearity fiber is numerically simulated. Performances of converted NRZ signals from RZ data streams with different duty cycles are analyzed and compared. Results indicate that the duty cycle of RZ data does affect the converted NRZ signal, with a rational value between 30% and 50%. Meanwhile, RZ to NRZ format conversion is experimentally demonstrated at 10 Gb/s data rate with 33% duty cycle. Signal spectrum before and after HNLF, typical eye diagrams and bit-error-rate (BER) are measured. Less than power penalty 1 dB is obtained in bit error rate 10-9 after the format conversion. Further experimental results confirm the feasibility in 160 Gb/s high-speed systems.