FM-FDM OPTICAL CATV TRANSMISSION EXPERIMENT AND SYSTEM-DESIGN FOR MUSE HDTV SIGNALS

We have developed FM-FDM optical transmission equipment for 34-channel MUSE HDTV signals to realize optical CATV systems. This equipment uses an LD with 1.3 urn wavelength, a single-mode optical fiber, and an APD. A good picture is received after a 42 km transmission. A part of the multiplexed signals is distorted near or below the threshold of an LD. When the number of transmission channels is small and the total optical modulation depth is large, this nonlinearity governs the power ratio of an FM signal to one distortion component—the DU ratio. However, when the number of transmission channels is large, the DU ratio is determined by the effective optical modulation depth rather than the total optical modulation depth. Furthermore, we clarified the method of system design for an optical trunk line CATV system. If no restriction of the transmission bandwidth of optical devices exists, approximately 30 km transmission of 100-channel MUSE HDTV signals is available with a received CN ratio of 17.5 dB. © 1990 IEEE