In this paper, an ultrabroadband optical access system for a future multimedia infrastructure, Gigabit-to-the-home (GTTH), is described. GTTH is based on a fiber-to-the-Home (FTTH) architecture and offers a very large downlink capacity of 2.5 Gbps. Because of this large downlink capacity, various broadband communication services and digital broadcasting services with hundreds of video programs can be simultaneously provided. GTTH also has high flexibility due to its multiple-interface architecture based on a bit multiplexing/demultiplexing scheme, which enables hybrid integration of multiple systems regardless of their signal formats, protocols, and transfer modes. A laboratory model of GTTH was developed. The optical network unit was achieved with small size, low power consumption and high receiver sensitivity by using a one-chip receiver IC, a high-speed CMOS demultiplexer, and a super lattice avalanche photo diode, which are newly developed for GTTH. The system demonstrates the service integration capability by simultaneously providing an ATM-based broadband communication service with the transmission capacity of 156 Mbps and multichannel broadcasting services with 300 video programs with MPEG2 format.