A MEMS-based optical, wireless communication system (10) that is comprised of a receiving and transmitting optical unit (12) that is further comprised of a transmitting subsystem (14) and a receiving subsystem (60), both of which are controlled by a microcontroller (16) and firmware (96). The system (10) is designed to allow a first unit (12) to transmit through free space a modulated laser beam (39) that is received by a second unit (12) located within line-of-sight of the first unit (12). Conversely, the second unit (12) can likewise transmit a modulated laser beam (39) that is received by the first unit (12) or other line-of-sight units (12). The system (10) features a MEMS mirror assembly (34) that operates in combination with a quad sensor (100). The combination allows fast, precise tracking and compensates for atmospheric disturbances associated with optical communication namely, building sway, wind and scintillations caused by changes in the refraction index of the atmosphere.