Technical Study On40Gb/s RZ-DQPSK Transponder Module

The wide scale move to40Gb/s transport in communications networks is an importantdevelopment for the communications industry, presenting exciting challenges for suppliersof the required technology. Early40Gb/s DWDM deployments were diven by the need toconnect40Gb/s router interfaces across core networks. For first generation40Gb/stransport systems, the network infrastructure was determined by the state of the arttransport products of the day.40Gb/s is get more and more extensive application around the world as one of thetechnologies that can effectly solve the pressure of bandwidth brought by mass business.Globally, most operators commonly used the technique, in order to provide moremetropolitan area and long distance network bandwidth. Large bandwithd, many businessload demand and operators face cost pressure, drive metropolitan area network structurechange, also drive the40Gb/s OTN application.When evolving the network from10Gb/s to40Gb/s, and in the future to100Gb/s, theselected solution must continue to meet the objective of delivering an Adaptive All OpticalIntelligent Network. To be more precise, for the higher rate solution to be volumedeployable, the following criteria must be met:(1)have similar deployment and operationalconditions as the current system, despite Chromatic Dispersion(CD), Polarization ModeDispersion(PMD) and Optical Signal-to-Noise Ratio(OSNR) constraints.(2)Be scalable,i.e.,suporrt50-GHz spacing.(3)Maintain complete agility required to meetever-changingservice requirements(ROADM flexibility).(4)Be cheaper than today’sequivalent capacity solution(i.e.,40Gb/s must be cheaper than4×10Gb/s).The key issues for pgrading transmission network speed is discussed based on thediscussion of the necessity of network speed upgrade and network acceleratedimplementation, including the modulation meanssignal receiving scheme, OSNRtolerance,PMD tolerance and so on. Secondly this paper analyzes one of the key parts of40Gb/s DWDM communication system—40Gb/s RZ-DQPSK transponder module, and provide the general structure design, the control scheme of emission and receiving part andthe high-speed PCB design signal integrity, power integrity, EMI/EMC int the existingproblems and solving schemes, makes clear the module design basic idea, the maintechnical methods and puts forward the feasible design scheme. Finally, the experimentalresults show that the module various performance indeicators have reached theinternational shandard, thansmission rate get promoted, it can meet the current and futurewithin five years business development needs.