State-of-the-art 60 GHz, 3.6 k-ohm transimpedance amplifier for 40 Gb/s and beyond

A 3.6 k/spl Omega/ InP HBT transimpedance amplifier (TIA) has been demonstrated with a bandwidth of 60 GHz. Gain flatness of /spl plusmn/2 dB and DC power of 271 mW has also been obtained. This TIA benchmarks the best gain-bandwidth product (GBP) of 1.9 THz, the highest transimpedance-bandwidth product (TZ-BWP) of 216 /spl Omega/-THz, and the highest TZ-BWP per DC power efficiency of +797 /spl Omega/-GHz/mW obtained for a 40 Gb/s transimpedance amplifier. These results are discussed in context with prior state-of-the-art 40 Gb/s TIAs implemented with various technologies and circuit topologies. 40 Gb/s photo-receiver requirements, TIA technology and topology trades, and future directions are reviewed.

Introduction

At 40 Gb/s, photo-receiver performance is dependent on several factors: (1) photo diode optical and electical performance such as responsivity, carrier transit time limit, and RC electrical parasitics, (2) transimpedance amplifier semiconductor performance such as gain, noise, overload, and bandwidth, and (3) integration parasitics such as.series input inductance and stray capacitance. While the photo diode technology sets the physical limit on sensitivity and bandwidth performance in a receiver, the choice of TIA technology and design approach strongly determines overall receiver performance.