Performance analysis of coherently detected orthogonal wavelength division multiplexing scheme

In this paper, a highly spectrally efficient scheme orthogonal wavelength division multiplexing with coherent detection (Co-OWDM) is analyzed. We study the effect of channel spacing on inter-channel crosstalk induced power penalty and on decision threshold Q-factor; effect of number of channels on Q-factor is also discussed. Results obtained with coherent detection are compared with direct detection technique. We also analyzed Co-OWDM with quadrature phase shift keying (QPSK) technique, passive micro-optics based 90° optic is used for coherent detection in this technique. QPSK based Co-OWDM system performance is analyzed in terms of bit error rate (BER) and quality factor.