This paper presents a simulation based demonstration of comparison between different modulation techniques for higher bit rate transmission under the effect of 2^nd order polarization mode dispersion (PMD). 2^nd order PMD is more dominant at higher bit rate, therefore it thresholds the transmission of higher bit rate to some limit. In this paper different modulation techniques have been compared on the ground of different signal parameters while varying the 2^nd order PMD coefficient value from minimum to maximum. To compensate 2^nd order PMD a post compensation technique is practiced in the simulation set up however it doesn’t compensate the 2nd order PMD completely but up to some extent so that signal could be retrieved at receiver properly after travelling through a long fiber span. The signal strength is measured by some parameters eye diagrams, Q-factor and BER values. The more opening of eye shows the better signal quality, also the higher value of Q-factor shows that signal is retrieved at the receiver properly.