Some additional results in optical CATV system developing

In multi-channel TV transmission via optical fibers laser nonlinearity problems can be partly overcome if light intensity is modulated by one or several frequency modulated microwave subcarriers. It turns out that in this design the linearity-problem is transferred from the laser to subcarrier FM modulator and demodulator. The basic theory and the experimental verification of the SCM-FM-CATV system was published by the authors and others. In the so-called group modulation method several sizes AM-VSB EM systems are applied together. In this solution the optimal linearity of frequency modulators and the laser modulator can be insured. In the present paper we deal with some additional problems and the ways how to overcome them.