Consideration on the Expression of Amplification Function of PTT with Positive Feedback Circuit Based on Approximated Characteristic Equations of LED and PD

Abstract

In 1989, B.J. Van Zeghbroeck et al., who was working for IBM Research Center at that time, announced the notion of PTT (Photon Transport Transistor) as an optical coupling device of light emitting diode (LED) and light receiving diode (Photo Diode, PD), where the carrier of the base layer is light (Photon) only. Later, it was theoretically shown that PTT has an amplification function in a positive feedback circuit and works as an extremely low-noise transistor element. In this paper, based on the characteristics of the electronic circuit including the LED and PD, we discuss the expression of the amplification function of the PTT positive feedback circuit. First, we theoretically formulate the fundamental equations for the circuit based on Kirchhoff’s Law and V-I characteristics of LED and PD. Second, we perform the actual circuit operation experiments of PTT positive feedback circuit. Lastly, we analyze the expression of amplification function and its operational behavior based on the measured values in the experiments, using approximated characteristic equations of LED and PD.