Lightweight high-data-rate laser communications terminal for low-earth-orbit satellite constellations

An optical terminal is described that supports bi-directional communications among a constellation of low-Earth-orbit satellites. The concept uses AlGaAs semiconductor diode master oscillator/power amplifier laser transmitters, a silicon charge-coupled device array for acquisition and fine tracking, and a silicon avalanche photodiode for 1-Gbps communications over a 4000-km range. The 19-lb laser terminal consumes 31 watts of peak spacecraft power.