抄録
Recently several new WDM/SCM optical transmission systems have been developed, to enable a higher transmission capacity of access networks such as CATV. Analog transmission performance of optical amplifiers and optical filters is important for these systems. Yet, there have been few studies that addressed this issue. In this paper, the required performance of optical devices and a system design method are investigated. In our study, we focused on the technical issues essential for 10, 000-channel WDM/SCM (32 WDM×310 ch SCM) systems using cost-effective direct modulation schemes. First, the mechanisms of sub-carrier level variation and distortion generation caused by FM-AM conversion on optical filters were examined both theoretically and experimentally. The required bandwidth of optical filters suitable for these systems was calculated. We then estimated the optical distribution number depending on the optical signal power input into EDFAs. We found that a configuration using three cascaded EDFAs enables developing 10, 000-channel WDM/SCM systems with 8, 000 distributions.
