A review is made of the present state of laser communications. The basic characteristics of lasercom are discussed, and the advantages and shortcomings are delineated. Potential application scenarios are given. A functional block diagram showing the major blocks is discussed, and each is described in terms of present performance parameters. Performance numbers are given in terms of range and bit error rate achieved. Discussion of the various available laser transmitters is given including the advantage and disadvantage of each. CO2 being a gas discharge device has potential lifetime problems and requires heterodyne detection - an added complexity. Nd:YAG requires either discharge lamp pumping or diode pumping. Diode pumping involves matching the diode emission line to a fairly narrow Nd:YAG pump band. There is an unresolved question of diode emission line shifting with age. A summary of the various shortcomings in the technology include, for example, the required heavy optical bench, lack of demonstration of 10-year required life, solid state detector response time, and photomultiplier tube lifetime.
"Laser Space Communication Technology Status", Proc. SPIE 0295, Control and Communication Technology in Laser Systems, (21 December 1981); doi: 10.1117/12.932402; https://doi.org/10.1117/12.932402