DIRECTLY MODULATED CATV TRANSMISSION-SYSTEMS USING HALF-SPLIT-BAND AND WAVELENGTH-DIVISION-MULTIPLEXING TECHNIQUES

We present a directly modulated NTSC AM-VSB 80-channel fiber optical C ATV long-distance (over 80 km) transmission systems by using 1550-mn d igital disstributed-feedback laser diodes, half-split-band, wavelength division multiplexing and erbium-doped fiber amplifier-repeated techn iques. Good performances of carrier-to-noise ratio (greater than or eq ual to 50 dB), composite second-order (greater than or equal to 68 dB) , and composite triple beat (greater than or equal to 63 dB) are obtai ned after 80-km standard single-mode fiber transmission. The proposed directly modulated transmission systems are simpler and lower cost tha n conventional externally modulated transmission systems.