1047-nm master oscillator power amplifier free-space optical communications laser transmitter

We report on the performance of a 1047-nm laser diode master oscillator (MO) diode pumped Nd:YLF power amplifier (PA) laser transmitter in a 50-Mbps quaternary pulse position modulation (Q-PPM) free-space optical direct detection communications experiment. The transmitter produced greater than 1 W of 1047-nm average optical power. At optical transmitter powers up to 0.2 W, we achieved nearly the same communications performance (/spl sim/210 photons/b at 10/sup -6/ bit-error rate) using the 1047-nm MOPA transmitter as with the 50 mW laser diode alone. We relied on an external-cavity grating feedback scheme for the 1047-nm laser diode MO to achieve this communications performance.