Abstract
AMI encoding of FSK data was used at the transmitter of a 622 Mbit/s optical transmission system which used a Fabry-Perot etalon to demodulate the signal. An optical preamplifier was used prior to the etalon, giving a 6.2 dB improvement in sensitivity of −31.2 dBm at 10−9 BER. The amplifier also contributed noise which was not completely filtered out by the etalon. Improved amplifiers and higher resolution filters should make high sensitivity receivers in FDM network applications possible.