Linearity analysis of uni-traveling carrier photodiode for MM W applications

This paper proposes a method of linearity analysis of uni-traveling carrier photodiode (UTC-PD) by using an electrical circuit model of the device. Based on this circuit, third order inter-modulation products are investigated by employing two tone input signals. The resulting fundamental, inter-modulation distortion products and the third order intercept point (IP3) agrees well with reported data. The effect of device mounting chip and package parasitic effects on IP3 is investigated in detail. It is shown that the linearity of the device is improved by decreasing the carrier transit time in the absorption layer. It is also found that IP3 decreases with increasing fundamental frequency as experimentally reported.