Fiberoptic transmission systems are based on the transmission and reception of intensity-modulated optical signals. Within these networks, optical amplifiers are deployed to compensate for fiber propagation and optical splitting losses~1. Both high-speed digital and CATV transmission are used placing significant demands on the fidelity of the transmission network. Optical amplification of intensity-modulated signals also imparts intensity noise which degrades the signal-to-noise ratio at the amplifier output terminals. The improtance of intensity noise is illustrated in Figure 1 by the figures of merit describing signal or transmission quality that are based on intensity measurements. Figure 1 shows how Q, bit-error rate (BER), relative intensity noise (RIN), and received signal-to-noise ratio (SNR) all depend on measurable intensity noise.
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