Date Added: Dec 2009
For 40 Gb/s optical communication systems, high-gain and high-bandwidth optical receivers are required, which inevitably require optical component modules and electrical component modules. The electrical component modules include a 40 Gb/s transimpedance amplifier and a post amplifier. A preamplifier is typically used as the input stage of the receiver in order to convert the small current from the photodiode into a voltage signal for amplification by the subsequent post amplifier. This stage is one of the key circuits in the optical link since it largely sets the sensitivity and maximum bit rate of the receiver. Transimpedance feedback amplifiers are commonly used as preamplifiers with low-input impedance and flat-gain characteristics.