GaAs f.e.t. transimpedance front-end design for a wideband optical receiver

A GaAs f.e.t. transimpedance front-end amplifier was built and operated as part of a regenerator at 274 Mb/s. The noise characteristics were optimised for operation with a Ge photodiode at 1.32 ¿m, but were measured at 0.82 ¿m to compare Si and Ge photodiodes. The amplifier input capacitance was 3.2 pF with the Si p-i-n diode and 4.6 pF with the Ge diode. At 0.82 ¿m, we measured a sensitivity for 10¿9 error rate of about ¿35 dBm with the Si diode and ¿32 dBm with the Ge diode. We predict a sensitivity of ¿34 dBm at 1.32 ¿m.