Since the 1990s the IAC has participated in the development of the first generation of experimental terminals for optical communications between satellites, housing the ground terminal test systems. The first of these terminals, called SILEX, has been used in the first European optical inter-satellite link (ARTEMIS, located in geostationary orbit, and SPOT IV in low orbit). Since 2001 the IAC has participated in optical link experiments with many satellites of the most important spatial agencies in the world: ARTEMIS, SMART-1, N-FIRE, TERRASAR-X, OICETS, LADEE, ISS ... These experiments have brought the optical terminals for use to geostationary orbits, to a state of sufficient maturity to transfer future developments to private industry. The developments of these technologies have a wide impact both in the study and observation of our planet and in space communications. In addition to the undoubted advantage of increased bandwidth, which allows to increase the flow of information and eliminate restrictive regulations in the use of radio frequencies, optical communications have other not insignificant advantages: confidentiality in transmissions and reduction of weight, volume and energy consumption of communications equipment of satellites that extend their life considerably. Currently, the IAC participates in the design of optical terminals for communications with deep space missions, in what constitutes the next frontier in this field of technology.