Seven types of GaAs ICs (integrated circuits) have been successfully developed specifically for use in 2.4-Gb/s optical transmission systems. These ICs are a laser driver, a 4:1 multiplexer, a 1:4 demultiplexer, a preamplifier, a gain controllable amplifier, a main amplifier, and a decision circuit. The ICs were fabricated using 0.8- mu m-gate self-aligned MESFETs. They were observed to continue to operate properly even at clock frequencies higher than 2.4 GHz.<>