Distortion and noise properties of a praseodymium-doped fluoride fiber amplifier in 1.3 /spl mu/m AM-SCM video transmission systems

The distortion and noise of a praseodymium-doped fluoride fiber amplifier (PDFA) are measured in two 40-channel AM-SCM video transmission systems. While it is already known that with direct modulation a PDFA leads to increased composite second-order distortion (CSO) and cross-modulation distortion (XM), this letter introduces an external modulation scheme that completely eliminates both problems. One PDFA is examined and found to yield low distortion and high CNR, but this is offset by a low-frequency noise. This noise is significant and the resulting picture quality is "annoying" in subjective tests.<
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