INVESTIGATION ON TRANSMISSION CHARACTERISTICS OF 40 GB/s OPTICAL NETWORKS BASED ON DUOBINARY MODULATION

摘要

A novel method to generate optical duobinary (ODB) modulation format and its transmission characteristics in 40 Gb/s optical networks, compared with conventional modulation formats such as return-to-zero (RZ), non-RZ, and carrier-suppressed RZ in cascaded optical networks, is proposed and analyzed in this article. The transmission performances of these four modulation formats in terms of the capability of resisting the nonlinear effect of a fiber is investigated theoretically, for instance, self-phase modulation, cross-phase modulation, and four-wave mixing. The chromatic dispersion tolerance of the four modulation formats mentioned above is also compared. The simulation results clearly show that the ODB modulation format has wider chromatic dispersion tolerance relative to the other formats. Moreover, after long-haul transmission, the duobinary format signal has the lower bit-error-rate and higher receiving sensitivity compared with conventional format signals.