Broadband communication using satellites requires use of the Ka band. Services of this type are now emerging all over the world, some with capacities in excess of 100 Gbps. However, as radio bandwidth resources become exhausted, high-speed optical communication can be used instead to achieve ultra-broadband communications. The National Institute of Information and Communications Technology (NICT) in Japan researches and develops the next generation of space communication technology. A hybrid satellite communication system using radio and optical frequencies is being studied. Here, the research and development activities of NICT are introduced, along with the concept of the hybrid high-throughput satellite communication system with an optical feeder link. Examples of link budget analyses for 10-Gbps laser communication links are given for satellite links between the ground and geostationary Earth orbit.