LARGE-SIGNAL CHARACTERISTICS OF INP-BASED HETEROJUNCTION BIPOLAR-TRANSISTORS AND OPTOELECTRONIC CASCODE TRANSIMPEDANCE AMPLIFIERS

A large-signal model for InP/InGaAs-based single HBT's incorporating s oft-breakdown effects to the LIBRA Gummel-Poon (GP) model is developed and its validity is established from DC to microwave frequencies and over a wide range of input excitation levels. The large-signal charact eristics of a cascode InP-based transimpedance optoelectronic preampli fier employing such devices are studied, Gain compression for the prea mplifier was found to take place at an input power level of -20 dBm, I nput power excitation varying from -65 to -5 dBm results in a degradat ion of the amplifier transimpedance gain of the order of 3 dB Omega, E xperimental and theoretical characteristics are presented for the InP- based HBT's and transimpedance amplifier, Self-biasing effects are sug gested as possible origin of the transimpedance variations with input power.