Investigation On 50Gbps TDM-PON Downsream Transmission Scheme And Digital Signal Processing Key Technology

From the long-term development of the network,with the increasing and sustainable development of new services like cloud computing,cloud storage,interactive ultra-high definition video,and with the increase of users,the demand of business and individual users for traffic is increasing.Therefore,the demand for network access bandwidth has maintained a high growth rate,and put forward higher requirements.As the most promising FTTx implementation technology in the world,PON technology has become the most mainstream solution of FTTx.With the increase of deployment scale,construction costs continue to decrease,making PON technology more competitive and widely recognized in the world.From the current development and application of PON,in order to meet the needs of high capacity and high speed,the next generation optical access technology after 10G capacity PON has become an urgent need.As an important solution of next generation large capacity optical access network,TDM-PON has great advantages in cost,actual deployment and technology maturity.Therefore,high-speed TDM-PON is one of the important solutions for next generation high-capacity optical access network.This paper mainly focuses on the design of 50Gbps TDM-PON reliable and low-cost downstream transmission scheme and key DSP technology.The main research work is as follows:The common fiber transmission impairments in high-speed optical access network is theoretically analyzed,and the factors restricting the high-speed optical communication system are researched.We comprehensively research and compare different modulation formats at 50Gbps rate,such as dispersion and noise tolerance,receiver sensitivity,spectrum efficiency,complexity and cost of high frequency spectral efficiency modulation format generation such as MPAM,Nyquist MPAM,duobinary and 16QAM.A downlink transmission scheme of intensity modulation direct detection 50Gbps TDM-PON based on MZM is proposed.MZM modulator has high integration.The received intensity signal based on intensity modulation directly detection only carry valid information in amplitude.Frequency offset and phase do not carry valid information.Carrier frequency offset and carrier phase recovery are not needed,which reduces the cost of the system and the performance requirements of the transmitter and receiver lasers.Direct detection technology is used to reduce the complexity of equalization algorithm for receiver DSP.Three adaptive equalization DSP algorithms are studied and analyzed to compensate transmission impairments.The 50Gbps TDM-PON downstream transmission scheme mentioned above is verified by off-line experiments using actual commercial devices.