دانلود رایگان مقاله خصوصیات 40 گیگابیت در ثانیه در مسافت طولانی سیستم انتقال چند کانال

Abstract

When updating the 10 Gbps optical transmission system to 40 Gbps, the main limits are chromatic dispersion, nonlinear effect, especially the interactions of dispersion and intra-channel nonlinearity. To optimize the performance of standard WDM in a 40 Gbps four-channel transmission system, numerical simulations are carried out to compare three different dispersion compensation techniques (without compensation; periodic dispersion compensation at the front end; and dispensation compensation all at the end of the system by means of highly dispersed pulses) for chromatic dispersion on a terrestrial 40 Gbps system. Both the loss and dispersion of the transmission fiber are periodically compensated, since two dispersive elements are placed at the input and the output ends of a compensation period. Due to the interplay between dispersion, nonlinearity and signal power, and the effect of dispersion on the pulse evolution, the pulse compress can be optimized and the system performance can be improved to compare with the system with either pre- or post-dispersion compensation. On comparing pre- and post-compensation methods, it is found that the latter is superior to the former. Further performance optimization includes how to properly match the EDFA power and length of the fiber.

4. Conclusion

Chromatic dispersion is a critical issue which can severely influence system performance at 40 Gb/s, and such a compensation tenability should accommodate multiple WDM channels. Since dispersion compensation is the technique used in fiber optic communication system designed to cope with the dispersion introduced by the optical fiber [18,19], the paper focuses on reporting a detailed investigation of 40 Gb/s WDM transmission experiments using periodic dispersion compensation and dispersion slope compensation. Pre-compensation decreases the signal power faster, and the signal experiences normal dispersion while signal power is higher; whereas in post-compensation, the signal power falls more slowly and the signal experiences anomalous dispersion while the signal power is higher. Pre-compensation has also been shown to result in pulse compression due to self-phase modulation (SPM), rather than the more detrimental pulse broadening effect that occurs in post-compensation. Optimally adjusting the compensation ratio of each channel will further improve the transmitted distances.