LARGE SIGNAL POWER PENALTY ANALYSIS OF FM-AM CONVERSION IN DISPERSIVE OPTICAL FIBRES FOR PCM SYSTEMS INCLUDING HIGHER ORDER DISPERSION

摘要

In this paper, by using large signal analysis for dispersive optical fiber, power penalty analysis for the FM-AM conversion with respect to binary intensity modulated PCM systems including second order dispersion term is discussed. The modified expression for power penalty has been derived and it's impact on laser line width and bit rate has been investigated. For power penalty less than 0.5 dB, the plots between bit rale and transmission distance are plotted above and below modulation limit. It is seen that the transmission distance increases with decrease, in linewidth over significant bit rates. The transmission distance with first order dispersion term for 300 MHz. line width is approximately 800 km,. With proper first order dispersion compensation i.e. with second order dispersion only, the transmission distance can be enhanced to 10~8 km for this linewidth. The line width requirements for systems with different bit rales and transmission distances are also calculated and discussed,. Further, it is seen that by including the second order dispersion term, the bit rate and transmission distance decreases decreases. For higher linewidths, this decrease is very less and as the linewidth decreases, the decrease increases. For 300 MHz line width, the decrease in transmission distance is just 30 km and for 30 MHz line width, the decrease is approximately 600 km over significant bit rates.