In this paper a transimpedance amplifier in 0.18mm CMOS technology for optical communication networks is proposed. In this design an RGC preamplifier is used as input. The RGC structure is applied to input in order to increase trans conductance and reduce input impedance. This structure neutralizes the effect of the photodiode parasitic capacitors at input of transimpedance amplifier due to low input impedance. The circuit uses capacitive degeneration and broadband matching network techniques and is designed to have bandwidth of 20 GHz, transimpedance gain of 60dBW and input-referred noise current with spectral density of 12 pA/sqrtHz in the ampli?er frequency band. Also results including input referred noise and transimpedance gain was confirmed after layout implementation in cadence, where post layout simulation was performed considering parasitic capacitors.