Research In 40Gbps DWDM NRZ Transponder

With the development of the high-speed internet,video service and large-capacity private line service,the demand of the network capacity is guadually increasing,which makes the network toward larger capacity, higher speedsand more long-rang, and the 40Gbps transmission business is put on the agenda to become the focus of concern of the industry. At the same time dense wavelength division multiplexing (DWDM) technology, greatly improves the transmission capacity of optical fiber transmission system to improve utilization of the optical fiber. The use of the DWDM makes the trasmission capacity expansion of dozens or even hunreds of times, while taking the full use of the huge potential bandwidth of the optical fiber; allows the customers to tansfer any protocal and format of the signal freely which greatly improves the network scalability and competitiveness, DWDM system can make the network offer new serivces quickly by simply increasing the wavelength, and give a broad development prospects of the optical fiber communication.This research is intent to develop the 40Gbps tunable transponder module. The 40Gbps DWDM NRZ transponder is based on the short way 40Gbps NRZ transponder, but adds the function of wavelength tunable and modifies the design of transmit unit. This paper introduces the background, significance, trend, innovation and related protocols at the beginning. The third chapter introduces the topic of the 40Gbps transponder module works as well as the overall diagram. The forth chapter foucses on the issues inculding the key technologies and the main circuit:modulation coding techniques, multiplexer/demultiplexer techniques, the temperature control of the laser, and the drive circuit of the driver, the bias voltage control design of LiNbO3 modulator ensures the modulator operating normally by a feedback of an added dither signal and the PIN-TIA receiver circuit. The wavelength control circuit of tunable laser uses a wavelength locker circuit to ensure the wavelength tunable available and stabilization at the high and low temperature. The fifth chapter introduces the topic of the 40Gbps DWDM NRZ transponder module test platform. The sixth chaper of this issue is the main topic of this summary of actual as well as the prospects for the next step.The detailed design of this research ensures the success of the module. Each of the performance meets the requirement which offers a contribution to the development of the 40Gbps optical modules.