The Investigation On 40Gb/s/? WDM-PON System And Colorless ONU

With the rapid development of the Information Society,the types of data services are enriched.End-end services such as IPTV,video on demand,high-definition TV and other multimedia data services become so popular,that IP data traffic grows fast,network bandwidth need to be improved urgently.Being likened to the route of "last kilometer" to users,access network plays a vital role on the performance of the entire network.As current growing data traffic put forward higher requirements on access network bandwidth,capacity,it is necessary to study on the large-capacity high-speed next generation access network.WDM PON with its large capacity,wide coverage,transparent transmission and good compatibility is considered to be one of the best options for broadband access and in recent years,it has received widespread attention and in-depth study.40Gb/s/? WDM PON system is one of the research emphasis at present.This paper focuses on 40Gb/s/? WDM PON system solutions including the research on order modulation scheme,colorless ONU and parallel receiving technology.The main research contents are as follows:1.Analysis and comparison of the 40Gb/s WDM PON system uplink and downlink transmission scheme.Compare coherent PM-DQPSK,4PAM,three-level double binary,DQPSK modulation format from transmission performance,complexity and cost and other aspects.Proposed tunable lasers based DQPSK uplink transmission scheme and OLT emitting uplink optical carrier based amplitude modulated three-level duobinary uplink transmission scheme.Analysis and simulation results show that compared with non-coherent receiver,coherent receiver's sensitivity has obvious advantages,and that compared with phase modulation formats,amplitude modulation eye diagram deteriorate significantly,while for phase modulation formats such as PM-DQPSK,the electrical domain equalization algorithms is mature and can better compensate the fiber channel damage.So downstream coherent PM-DQPSK,upstream self-coherent DQPSK is more in line with the requirements of system performance and cost.2.Adaptive tunable laser wavelength tuning methods are studied and an uplink optical reflected wavelength tuning method is proposed.Based on the tunable laser,to improve the transmission capacity of the system,a wavelength shift channel-reuse WDM PON scheme is designed.The uplink optical reflected wavelength tuning method and wavelength shift channel-reuse WDM PON system performance are tested through experiment.The experimental results verify the validity of the adaptive wavelength tuning method,and system sensitivity shows that the wavelength shift between uplink and downlink could eliminate the impact of reflected uplink optical and Rayleigh scattering noise.3.To achieve 40Gb/s WDM PON system clock synchronization,receiver clock synchronization algorithm is studied.Through analysis,paper found that improved Gardner algorithm can achieve clock synchronization for multi-modulation.Using improved Gardner algorithm,paper simulated three-level amplitude modulation double binary clock synchronization.To reduce the cost of the electronics in receiver,the parallel clock synchronization algorithm is studied.By serial to parallel conversion,receiver lowers the processing speed requirements for the electronics,thus reduced the system cost.