Noise properties in cascaded erbium-doped fiber amplifiers used in subcarrier multiplexed analog video distribution systems are experimentally examined. The noise dependency on signal wavelength is measured for a 4 stage EDFA cascade, and it is shown that an optical narrow bandpass filter is not necessary after each fiber amplifier for signal wavelength of 1.5511.560µm and that optical bandpass filters are necessary for shorter wavelength than 1.551µm to avoid the noise degradation by spontaneous-spontaneous beat noise. Finally, the attainable distribution loss is estimated for AM and FM video distribution systems.

An optical receiver for hybrid SCM video distribution systems that distribute AM, QAM (quadrature amplitude modulation) and FM TV signals simultaneously is investigated. We propose a novel receiver configuration called the Frequency Division type Receiver (FDR) with consists of a photo detector, filter, and multiple preamplifiers. The receiver is compared with existing receivers in terms of optical sensitivity, distortion characteristics, and configuration simplicity. We clarify that the newly developed FDR type receiver is most suitable for hybrid SCM video distribution systems.

This paper describes the impact of EDFAs on AM/FM FDM subcarrier multiplexing (SCM) all-fiber video distribution (AFVD) systems. As AM/FM hybrid system using EDFAs which can simultaneously distribute 11 AM-TV channels and 50 FM-TV channels is proposed and discussed. 4-stage amplifier-branch transmission experiments are introduced. The construction and performance of a newly designed 50 channel FM tuner are also presented.

Measurement results of two cascaded EDFAs (initial amplifier and boost amplifier) are reported for AM-FDM video distribution systems. A CNR of 55.5 dB and an output of 13.35 dBm (21.6mW) are measured. Distortion is measured by the two-tone method. On the basis of the measured distortion values, composite second-order distortion (CSO), composite triple beat distortion (CTB) and cross-modulation (XM) in a 40-channel transmission are estimated to be less than 56.9 dB, 66.3 dB and 74.6 dB, respectively. CNR values are strongly dependent on the erbium fiber length. They are degraded by light reflected from the input and output ports of the erbium fiber.