ESTIMATED PERFORMANCE OF 2.488 GB S CPFSK OPTICAL NONREPEATED TRANSMISSION-SYSTEM EMPLOYING HIGH-OUTPUT POWER EDFA BOOSTERS

The configuration of a practical non-repeatered coherent optical trans mission system and its performance are reported. The practicability of combining continuous-phase frequency-shift keying (CPFSK) with erbium -doped fiber amplifier (EDFA) boosters is verified by laboratory and f ield experiments. The system consists of a highly stable CPFSK transmi tter, a high-output power EDFA booster with automatic level control (A LC), and a highly sensitive heterodyne-polarization-diversity receiver with cold start automatic frequency control (AFC). A system gain of 6 0.8 dB is achieved at a BER at 10(-11); the EDFA's optical output powe r is +18 dBm and the receiver sensitivity is -42.8 dBm. The stimulated Brillouin scattering (SBS) effect is examined to estimate the depende nce of error rate characteristics on the bit sequence length. No power penalty is observed for a pseudo-random bit sequence (PRBS) of more t han 2(5) - 1 or STM-16 patterns containing a 30 byte block of consecut ive identical digits. The power penalty of 1.3 dB caused by the 310 km non-dispersion shifted transmission fiber is successfully compensated by installing a chromatic dispersion compensator in each orthogonal p olarization branch. During a four month field experiment, error-free o peration is observed over a 30 day period and the long term error rate is under 6 x 10(-16).