Millimeter wave generation and uni-traveling carrier photodiode design based on its nonlinearity

Nonlinear mechanism of photodetector in the communication band of 1550 nm was researched in this article. Then nonlinear frequency doubling mechanism was used to generate millimeter wave signals that can be used in millimeter wave communication systems. In the article, the layer structure of the photodetector was optimized to further improve the power of millimeter wave signals. Different from the fundamental frequency output power, the frequency doubling output signal exhibits completely different characteristics at low input optical power and high input optical power. Therefore, the structure design of the photodetector was optimized for different input optical power application scenarios. Finally, the influence of the incident optical field distribution on the nonlinear output of the photodetector was studied. The results showed that when the photodetector did not reach saturation, the Gaussian distribution situation could produce a larger nonlinear signal power than uniform distributed optical field.