Power Monitoring Method Of Optical Fiber Dispersion

Internet network that appeared at the end of the 20th century, indicates the human society enters into a brand-new era-Information Age. In this era, traditional communication technology has been difficult to meet requirement of transmission capacity that increase constantly. In optical communication, the distance without relay is restricted by loss and chromatic dispersion. The fiber loss can be compensated through the optical amplifier, especially through the Erbium-Doped Fiber Amplifier (EDFA). At present an important way to improve transmission capacity is to improve the transmission rate of the single wavelength. Now, the transmission rate of 10 Gbit/s has already begun commercialization. But with transmission rate's improvement and longer transmission distance, chromatic dispersion restriction to system are more serious. So chromatic dispersion monitoring on line and compensation have become more and more important. In this text the theory of the chromatic dispersion is deduced firstly and two chromatic dispersion monitoring methods are carried on emulational research at the VPI Transmissionmaker softwave platform. In chapter three and chapter four, the theory of the chromatic dispersion monitoring by intensity modulation and phase modulation are introduced and a concrete analysis of several systematic parameter, such as fiber loss, optical amplifiers, chirp of modulation, modulation coefficient, linewidth of laser and fiber nonlinearity, are made. Finally, a good result is received in a DWDM system by comprehensive optimization. From the emulation, we can make a conclusion that every parameters in the transmission system have a different effect on the power of the pilot tone. Some factors'influences on chromatic dispersion monitoring are analyzed by reasoning and digital emulation in this text and are optimized in two different DWDM real-time chromatic dispersion monitoring systems. The result shows not only the monitoring range can be enhanced but the range can be changed by adjusting the frequency of pilot tone. And the application of the two methods can improve the capacity of optic-fiber communication system and increase optic-fiber transmission distance. There are very great application prospects in ASON.