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The effects of relative intensity noise (RIN) on the multiwavelength optical orthogonal code-division multiple-access (OOCDMA) communication system is investigated with two-, three-, four-, and six-wavelength cases using an erbium-doped fiber laser, a graded-index multimode (GI–MM) fiber channel, and a direct-detection (DD) receiver assuming chip synchronization between user codewords, performing Gaussian approximation analysis. It reveals that RIN affects the error performance of the system significantly, for example, with w=3, Ps=-50 dB, RIN=-120 dB/Hz, s=10,000, and M=56, Pe is 9.09×10-9 compared to 1.72×10-14 without RIN, showing more than four orders of increase in magnitude. When Ps=-65 dB, Pe increases with an increase in the number of wavelengths w with RIN and without RIN for a specified modal parameter s. On increased power, say -50 dB, Pe decreases with an increase in w without RIN, while the variation with RIN is neither increasing nor decreasing uniformly for large values of s. This result in system error performance not only depends on the received laser power and the number of wavelengths, but also on the presence of RIN and the modal parameter. ©2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 24: 307–311, 2000. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The concept of a multiwavelength was recently introduced in order to support a large number of simultaneous users in optical code-division multiple-access (CDMA) networks without the need for complicated optical signal processing. A number of multiwavelength optical orthogonal codes (MWOOC) have been developed, and these codes show better performance under heavy traffic load conditions. In this paper, a complete analysis of the multiwavelength OOCDMA communication system is presented, including the effects of avalanche photodiode (APD) noise, thermal noise, and multiple-user interference for a direct-detection receiver. The results of the analysis are compared with the performance of an optical orthogonal CDMA system that uses only one wavelength, i.e., single-wavelength optical orthogonal codes (SWOOC). Typically, for 825, 826.1, and 827.2 nm, with -60 dB laser power and 50 simultaneous users, Pe is 4.17×10-15 compared to 1.77×10-5 at 825 nm in a SWOOC system. In the presence of various noises, the MWOOC system exhibits improved error performance over the SWOOC system. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 22: 182–188, 1999 [ABSTRACT FROM AUTHOR]

This letter analyzes the performance of M-ary orthogonal signaling in an FO-CDMA communication system employing optical orthogonal codes. The BER probability is evaluated by assuming Gaussian statistics for the receiver output. The numerical results illustrate that M-ary orthogonal signaling in an FO-CDMA system is a viable option to achieve a high-capacity communication network, but with additional encoder/decoder complexity. © 1997 John Wiley & Sons, Inc. Microwave Opt Technol Lett 16: 390–393, 1997. [ABSTRACT FROM AUTHOR]