Design and analysis of low noise transimpedance amplifiers for 10 Gbs optical receivers

High-speed optical systems are becoming increasingly important due to the progress of multimedia communications, which requires ever increasing data-transmission capacity. SONET based systems at 10 Gb/s are under commercial development, and it is likely that systems based on higher SONET hierarchies will soon be required for further broadband communications networks.This thesis describes a low-noise and low-power Si-bipolar transimpedance preamplifier for the front-end of an optical-fibre receiver using a 0.5 mum 25 GHz self-aligned double poly silicon bipolar process. Design specifications are met through trade-offs between input noise current, speed, transimpedance gain, power dissipation, impedance matching, and supply voltage. This was achieved by (1) using inductors to enhance the bandwidth, (2) using a tuned noise-matching network at the input to improve the signal-to-noise ratio (SNR), (3) and using frequency compensation techniques to improve stability and to further enhance the bandwidth of the preamplifier.In this thesis, the design of the amplifier is preceded by an analysis of four different circuit topologies, with focus on three main design parameters: bandwidth, input-referred noise, and power dissipation. This is followed by a discussion of the specific bipolar transimpedance amplifier (TIA) designed and fabricated, and the integration of an optoelectronic device model with the preamplifier for the purpose of testing. Design, simulation, layout and test data of the preamplifier are presented in detail. The performance of the TIA is finally discussed based on measurements