Repeater IC's for a high-speed optical submarine transmission system are integrated on five monolithic chips using a Si shallow junction bipolar process with 7 GHz fT. To achieve high reliability, a two-level metallization system using Cu-doped Al and Au//Pt/Ti with TiN diffusion barriers is employed. The gain (s21) and bandwidth of the equalizing amplifier IC are 65 dB and 300 MHz, respectively. The timing amplifier IC phase deviation is kept within 10°. The decision IC sensitivity is less than 6 mV. These results fully satisfy performance requirements for repeater IC's.