Research Journal of Engineering and Technology

Optical communication is an intensely high-speed growing technology, provoked by an ever-increasing need for expansion of internet all over the world. In this modern world, the concept of mixed line rate (MLR) in optical wavelength division multiplexed (WDM) networks has come forward as cost as well as power-efficient way out. In this paper we discuss the performance of single-line-rate (SLR) and MLR optical networks individually. We perform SLR and MLR analysis using various modulation formats at 10, 20 and 40Gbps and calculate the quality factor (Q-factor). Our focus is on selection of channel spacing, launch power, bit rate and link length. For data rates greater than 10Gbps, dispersion and nonlinearity are quite common. Thus in order to achieve efficient transmission, a pre-amplifier and a single-mode fiber (SMF) followed by a dispersion compensating fiber (DCF) is used. The results of our simulation indicate that for high transmission capacities, certain modulation formats show weak response while others show a good transmission reach. Q-factor and hence quality of transmission (QoT) can be improved by using shorter links with bit rate of up to 40Gbps or longer links with bit rate of 10Gbps and by increasing the channel spacing.