Wide-bandwidth photoreceiver GaAs preamplifier ICs using current-mode design techniques

The use of current-mode preamplifiers in optical communications systems has been shown to offer significant bandwidth advantages over traditional voltage-mode designs. High input-impedance common-source preamplifiers typically have a limited bandwidth of the transistor f_T. Low input-impedance common-gate preamplifiers allow this limit to be increased to better than f_T/4. A front-end stage based on GaAs current mirrors increases the bandwidth to approximately one-third of the transistor f_T