Wideband low-noise HEMT preamplifier for high-speed optical transmission

This paper describes a broadband low-noise preamplifier suitable for 40 Gb? s optical communication systems. To reduce the noise to the absolute minimum, a high impedance front-end, followed by an equalizer, has been designed. The circuit, based on 0.2 μm gate length HEMT technology, was characterized both in terms of bandwidth and noise performance. Measured results demonstrate the great interest of using low-cost wideband HEMT amplifier hybrid coupled to p-i-n photodiodes for OEIC receivers. Despite differences between simulated and measured results due to hard failures during the fabrication, the amplifier achieves a 40 dB trans-impedance gain over 35 GHz of bandwidth.