在分析相位整形不归零(PSNRZ)码基本原理的基础上，提出了一种利用马赫-曾德(MZ)调制器对信号相位进行预调制的方法，该方法能够方便有效地控制信号初始啁啾的形式和大小。文章指出调制深度可以更加直观地反映PSNRZ码的啁啾大小，并推导了调制深度与啁啾系数及链路残余色散之间的关系。最后，在40 Gbit/s通信系统中对PSNRZ码的性能进行了仿真分析，结果表明：PSNRZ码可将系统的色散容限提高到180 ps/nm，极大地降低了色散对通信系统的影响。

On the basis of analyzing the fundamental principle of the PSNRZ code, this paper presents a signal phase pre-modulation method using the MZ modulator, which can easily and effectively regulate the format and value of the signal initial chirp. It points out that modulation depth can more visually reflect the chirp value of the PSNRZ code and derives the relationship between the modulation depth and the link residual dispersion. Finally, it simulates and analyzes the performances of the code in 40 Gbit/s communication systems, which indicates that PSNRZ code can increase the system dispersion tolerance to 180 ps/nm, thus greatly reducing the effects of dispersion on the communication systems.