ANALYSIS OF THE TRANSISTOR-RELATED NOISE IN INTEGRATED P-I-N-HBT OPTICAL RECEIVER FRONT-ENDS

The equivalent-input-noise-current-spectral density for a monolithical ly-integrated optical receiver front-end employing InP/InGaAs heteroju nction bipolar transistors and a p-i-n photodiode has been computed fr om a small-signal model. Particular attention has been paid to the con tributions to the noise from the HBT in the first stage of the amplifi er. It is shown that with transistors designed for 1-10 Gb/s receivers the base current shot noise dominates in the frequency range 10 MHz t o 1 GHz, and both the base resistance thermal noise and the collector current shot noise are important at higher frequencies. Device feature s which determine the extent of these noise sources are identified, an d ways to improve the noise performance are discussed.