Methods, devices, and systems are described for free space optical communication. An example device can comprise a laser, a modulator configured to cause the laser to output an optical signal comprising a data signal and a beacon signal, a defocuser optically coupled to the laser and configured to receive the optical signal and control a beam divergence of the optical signal, an optical interface configured to receive the optical signal from the defocuser and output the optical signal into free space, and a controller configured to cause the defocuser to adjust the beam divergence based on an operational mode of the laser.