Analysis of multiwavelength OOCDMA system with laser phase noise, modal noise, MUI, and receiver noises

Abstract

It has been shown that the multiwavelength scheme exhibits better system performance in optical code‐division multiple‐access (CDMA) networks, particularly when the traffic load is heavy. This scheme supports a large number of subscribers and simultaneous users without using very large bandwidth or the need for complicated and expensive optical processing. The performance of the multiwavelength optical orthogonal CDMA system has been analyzed so far considering multiuser interface (MUI) alone. In this paper, the effects due to laser phase noise, modal noise, and receiver noises (APD noise and thermal noise) are also presented assuming a multimode fiber‐optic channel and a direct‐detection receiver. The analysis has been carried out by taking three wavelengths, i.e., 825, 826.1, and 827.2 nm, and the influence of each of the above noises on the error performance is studied. The results of the analysis reveal that, in the presence of MUI and receiver noises, if the signal power at the receiver is less, the effect of the laser phase noise on error probability is more significant compared to modal noise, whereas if the power is large, the contribution of laser phase noise is negligible. For the given received laser power, when the effect due to modal noise on error probability is higher, the effect due to laser phase noise is lower and vice versa. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 23: 299–304, 1999.