Design And Implemention Of A Novel Structure Of WDMA-EPON

While the backbone networks and local area networks spread their bandwidth fastly, the development of the access networks which link the two networks is much slower, and this is the well known"first mile problem". But since the twelve first century, new optical access network technology that EPON (Ethernet Passive Optical Network) get extensive attention from government and communication industry and hopefully resolve the problem. EPON usually use tree topology structure and broadcast/select method in downstream, and have well satisfied vastness consumer requirement currently, but due to use TDMA (Time Division Multiple Address) method in upstream, transmitter and receiver in upstream must use burst mode, and unfortunately it bring a series of technology problems.Along with the development and maturity of WDM (Wavelength Division Multiple) technology, using WDMA(Wavelength Division Multiple Access) method in upstream can well resolve the problems due to use TDMA and greatly increase upstream bandwidth. But restricting the application of WDM in access network is mainly because the number of ONU(Optical Network User) is much more than the number of wavelength that we can use and the high cost of optical device. This thesis aimed at how to resolve the two problem, and the main research content and result is as follows.(1) After deeply researching current all kinds of WDM-PON, we put forward a novel structure that combine WDMA and CSMA/CD(Carrier Sense Multiple Access) in upstream which can well resolve the problem that the number of ONU is much more than the number of wavelength that we can use, design a simple collision detection method and verify the feasibility of the structure.(2) We design and implement the upstream accurate wavelength optical transmitter that use self-fabricate low cost external cavity laser based on narrow band filter. We analyze the inside function mechanism of external cavity laser based on narrow band filter and high frequency modulation characteristic, and give detailed circuit scheme for laser drive circuit and temperature compensation.(3) We research and develop component integration technology of simply structure DTF(Dielectrics Thin—Film)demultiplexer and PIN-TIA detector array to fabricate low cost DWDM multi-channels receiving array module. We designed the whole structure of receiving array module, analyzed the function mechanism of DTF demultiplexer and give detailed circuit scheme for multi-channels receiving array module.(4) At last, We tested the external cavity laser, transmitting module and receiving array module in upstream, and give a conclusion and discussion of the whole thesis and presented some advise of the further research.