Performance Analysis And Application Of Novel10Gb/s Tunable Optical Transmitter Module

In recent years, the research and development of various devices and technologiesrelated to Dense Wavelength Division Multiplexing (DWDM) has been the mostimportant research direction of optical fiber communication. DWDM10Gigabit SmallForm Factor Pluggable (XFP) module is one of these hot spots. According to estimationby ICCSZ, the tunable XFP module will replace the current fixed-wavelength DWDMXFP module gradually. The critical technology of the tunable XFP is the tunable opticaltransmitter module, while there are little adequate manufacturers. In this thesis,preliminary study of the tunable optical transmitter module is performed before massproduction.Firstly, the theoretical reseach about the Digital Supermode Distributed BraggReflector (DS-DBR) laser and Mach-Zehnder (MZ) modulator is studied. The principleof tunable laser wavelength selection and MZ modulator modulation is analyzedsystematically. Mathematical model of the MZ modulator is established. Simulation ofnegative chirp and zero chirp MZ modulator is conducted to provide reference for thefollowing module performance test.Secondly, a simple automatic test system is designed and built up to test theperformance of laser and modulator. The current or voltage output of correspondinginstument is control by Visual Studio2005, meanwhile test data from test instrumentsare read and saved to Excel for analysis. Laser threshold current, output frequency andpower stability of all channals, extinction ratio and half-wave voltage parameters of themodulator are tested.Finally, the actual application of the module is simulated. The transmitter moduleis welded to a specially designed PCB and a10Gb/s high speed modulation voltagegenerated by PPG is connected to the two modulation arms of MZ via two coaxial cableconnectors. Then back to back eye diagram of the transmitter module, dispersionpenalty of75km long distance singnal transmission and Optical Signal Noise Ratio(OSNR) penalty of different transmission distance are tested. Eye diagram test showsthat extinction ratio is greater than12dB and template margin is greater than15%.Power penalty is less than3dB over75km transmission. OSNR penalty is less than1dB over dispersion range of-300ps/nm to1400ps/nm.All test results show that the module has good performance, and meet therequirements of the tunable DWDM XFP. This automatic test system can completenumerous tests accurately and quickly, and provides great reference value to the massproduction stage.