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.