Analytical Modeling of Speed Response of Heterojunction Bipolar Phototransistors

This paper describes a new comprehensive analytical charge-control model, which includes all the significant delays associated with heterojunction bipolar phototransistors (HPTs). A minimum number of approximations and assumptions have been made throughout its development. The model is accurate and predictive and provides an excellent insight into the operation of the HPT since the equations developed are based on fundamental charge control of the device operation. Realistic switching results up to 40 Gb/s, which are applicable to optical fiber communications systems, have been obtained, which emphasize the value of the model in the device optimization process