Abstract

ICs for 10-Gbit/s fiber-optic transmission systems have been actively developed. Several experiments on monolithic ICs^1-3 have been reported recently, but only a few optical receivers using monolithic ICs have been reported. We previously reported a 10-Gbit/s front-end module⁴ and a 3R transmission experiment,⁵ both using hybrid ICs, Monolithic ICs are important, especially for practical use where compact size is required. We have developed preamplifier, postamplifier, automatic gain control (AGC) amplifier, laser driver, and decision circuit ICs using AlGaAs/GaAs heterojunction bipolar transistor (HBT) technology. A 10-Gbit/s optical receiver has been fabricated utilizing the developed AGC amplifier and decision circuit ICs. In this paper, the system performance is described, ICs with low collector capacitance C_BC are important for achieving high-speed wide bandwidth characteristics. To reduce the collector capacitance C_BC, undoped GaAs is adapted to a collector layer. With this technology, HBTs with 2.5 x 5-µm² emitter showed that capacitance C_BC is 27 fF. This capacitance is low enough to build 10-Gbit/s performance ICs.

© 1992 Optical Society of America