Influence of reflected light on erbium-doped fiber amplifiers foroptical AM video signal transmission systems

Investigates experimentally the influence of reflected light on an erbium-doped fiber amplifier for use in optical AM frequency-division multiplexing (FDM) video distribution systems when reflection points exist before and after the amplifier. It is found that amplifier distortion is not affected by reflected light but that the signal gain and the noise figure of the fiber amplifier degrade with increased reflectivity. Gain was decreased by 3 dB when reflectivity after the amplifier was -12 dB. It was theoretically and experimentally clarified that the noise figure degradation was related to the internal reflection of the erbium-doped fiber, in addition to the reflection before and after the fiber amplifier. This internal reflection is caused by input signal light scattered within the erbium-doped fiber