Research On Multi-services Converged WDM-PON System With Centralized Lightwave

With the advent of the digital age, users not only ask Internet for higher transmission bit rate and larger capacity, but also require multi-services more and more strongly. In this context, developing multi-services based on huge bandwidth capacity WDM-PON system, is becoming a hot spot of optical access research.Currently, the researches on providing multi-services in OLT give some schemes such as using TDM technique, adding extra optical sources, or using optical sub-carrier multiplexing technique, these schemes need either precision timing devices,or extra light sources, would be very complicated when they are constructed and would cost a lot, and would waste part of the bandwidth in some cases; the researches on loading upstream in ONU most concentrate in schemes of using local optical sources or local amplifier, but these schemes also need high construction cost.This paper proposed a novel WDM-PON scheme, which used an orthogonal modulation format to carry multiple services in OLT and used the cost effective re-modulation technology in ONU to centralize the lightwave.This scheme employed 10Gb/s downstream DPSK signal and 1Gb/s downstream FSK signal to carry point-to-point data service and broadcast service respectively. At ONU, the scheme separated part of downstream signal as carrier to be modulated by upstream OOK signal. Finally, we did 20km transmission simulation between OLT and ONU and analyzed the performance by software simulation.The scheme this paper proposed realized a design that has no local optical sources in client, which agreed with the concept of colorless ONU, the scheme could not only save the cost of system construction, but ease the work of system maintenance and upgrade as well.What was more, thanks to the orthogonal modulation and re-modulation technology used in physical layer, there could be two kinds of downstream services and one kind of upstream service between OLT and ONU in just one single wavelength window, that meant this scheme could realize multi-services by fewer optical sources and devices. By analysis, the feasibility of this scheme was proved and a few of technique indicators related was given. The conclusion of this paper would benefit the construction of centralized lightwave multi-services WDM-PON greatly in the future.