1 GBIT/S COHERENT OPTICAL COMMUNICATION-SYSTEM USING A 1-W OPTICAL POWER-AMPLIFIER

An experimental 1 Gbit/s, coherent optical communication system that uses a 1 W semiconductor optical power amplifier is reported. The system is intended for use in free-space crosslink applications, operates at a wavelength of 972 nm and uses a frequency-shift-key (FSK) modulated semiconductor laser master oscillator, heterodyne detection receiver, and delay-line discriminator demodulator. Communication link sensitivities of 30 detected photons per bit at a 10(-6) bit error rate have been obtained. This link performance can support gigabit per second rates across geosynchronous distances.