DWDM Accurate Wavelength Transmitter Applied In EPON

In recent years, EPON(Ethernet Passive Optical Network) ,as a new access network technology, has drawn more and more attention from government and communication industry because it may be the best solution to "the last kilometer problem ".With rapid growth of market demand for broadband,especially FTTH rapid development,EPON ,as a new access network technology,would have a bright prospect. After simple comparision between TDMA (Time Division Multiple Address) and WDMA(Wavelength Division Multiple Address),the thesis points out that WDMA instead of TDMA can avoid many difficult technology problems. But in WDMA, specific and stable wavelength transmitter is essential. The thesis aims at how to design the transmitter module.The main parts are as follows:Points out technology problems in TDMA and advantages in WDMA.Explains operation mechanism of external cavity laser; Getting equivalent model for external cavity laser; Based on equivalent model,we can conclude some relation between threshold,output efficiency and couple efficiency,reflectivity of fiber grating; Taking external cavity laser as optical amplifier with delay, we can draw a form for side mode suppress ratio; Getting linewidth form for external cavity laser from semiconductor laser linewidth and then discussed it; From rate equation, we can get photon lifetime and resonance frequency which is related with parameters of external cavity.Present a type of dual-loop drive solution for laser on the base of IC.The dual-loop can adjust bias current and modulation current throught direct measure monitor photon current, Complete laser drive circuit design,PCB(printed circuit board) design and circuit test.Present a type of temperature control solution on the base of IC.The solution can enhance efficiency and decrease periphery elements because of combining linear drive and PWM(Pulse Width Modulate) drive;Complete laser temperature control circuit design,PCB design and circuit test.The transmitter ,which is composed of above drive circuit,temperature control circuit and laser,operates well in EPON system.