LOW-NOISE 8 GHZ PIN FET OPTICAL RECEIVER

An ultrawide-bandwidth, low-noise optical receiver has been designed for use in both multigigabit direct-detection or coherent heterodyne systems at 1. 3 and 1. 55 mu m wavelengths. The receiver consists of a low-capacitance InGaAs PIN photodiode connected to a high-impedance three-stage GaAs FET preamplifier. Inductive peaking at the front end is used to reduce the receiver noise at high frequencies. The receiver has an equivalent input rms noise current of less than 12 pA/ ROOT Hz from 4 to 7 GHz. The measured 3 db bandwidth of 8 GHz is claimed to be the widest receiver bandwidth reported to date.