偏振模色散补偿系统中新型调制格式的研究

Study of Polarization Mode Dispersion Compensation using New Modulation Formats

研究了不同调制格式应用于偏振模色散补偿系统的性能。从理论上和数值上分析了不同调制格式的偏振度(DOP)和偏振模色散(PMD)的关系,结果表明,不同的调制格式对应不同的频谱结构,因此对应不同的DOP灵敏度。另外,以DOP做反馈信号,比较了不同调制格式的PMD补偿性能,数值模拟结果表明,调制格式的信号谱宽越窄,PMD补偿效果越好。此外,差分相移键控(DPSK)的补偿效果要比传统开关键控(OOK)好;CSRZ由于具有更窄频谱结构和载波抑制特性,因此补偿效果要比RZ好;CSRZ-DPSK结合了CSRZ载波抑制特性和DPSK的特殊频谱特性,具有最好的PMD补偿效果。

The polarization dispersion compensation performance of different modulation formats is studied. Firstly, the relationship between the signal＇s degree of polarization （DOP） and polarization mode dispersion （PMD） of different modulation formats is analyzed theoretically and numerically. The results show that DOP sensitivity is different among the different modulation formats, because the change in data modulation format will often result in a change of optical spectrum. Secondly, the PMD compensation performance with DOP as feedback signal of the mentioned modulation formats is studied via simulation. It is shown that the modulation formats with smaller bandwidth have better PMD compensation performance. It is also shown that PMD compensation performance of DPSK is better than that of OOK, and that CSRZ, because of its specific spectrum characteristics, obtains better PMD compensation performance than that of RZ. CSRZ-DPSK combines the carrier-suppressed characteristic of CSRZ formats and specific spectrum characteristic of DPSK formats, thereby it has the best PMD compensation performance.