Performance evaluation of heterojunction bipolar transistors designed for high optical gain

This paper evaluates the performance of thin base Npn heterojunction bipolar transistors designed for high optical gain in the base while biased in the active regime. Pisces/Blaze simulations indicate that injected carrier concentrations exceeding 10¹⁹ cm^-3 can be achieved resulting in an estimated optical gain ~3000 cm^-1. Furthermore, a very large increase in differential base electron concentration with emitter current yields a high modulation depth with no insertion loss but low f_T. Estimated performance of this device in a microwave fiber optic link application is given