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.