Effects of relative intensity noise on a multiwavelength OOCDMA communication system

Abstract

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.