As the bit rate of the optical transmission system gets higher and higher, 40 Gb/s to 100 Gb/s, the modeling of proposed modulation techniques is very important so as to avoid costly practical demonstration. A Polarity Multiplexed-QPSK transmission system is modelled in MATLAB and simulated with Additive White Gaussian Noise (AWGN) added through the channel with Chromatic Dispersion (CD). Output is filtered and performance is measured and presented in this article.