Required quality for multichannel digital modulation signals in the transmission system employing optical super wideband FM technique

Summary form only given. Summary form only given. For multichannel video transmission, an analog SCM has been generally adopted. However, it requires a high carrier-to-noise ratio (CNR) and is sensitive to optical multiple reflections. A super wideband FM technique decreases minimum optical received power because of its FM gain and increases the tolerance against optical multiple reflections. Therefore, this technique promises to realize multichannel video transmission on conventional optical telephony networks. In this paper we examined the required DUR (ratio of the demodulated 64-QAM signal power to the total power of the undesired signals in the 64-QAM signalband) for each factor that affects the BER of 64-QAM signals on an analog/digital hybrid transmission system employing the optical super wideband FM technique. Our developed AM-40 channels/64 QAM-30 carriers transmission equipment, which satisfied the required DUR for each factor, achieved error free characteristics (<10/sup -9/) for 64-QAM signals on optical networks with a loss budget of 30 dB.