The Effect of Illumination Uniformity on the Saturation Characteristics of Photodiode

The saturation characteristics of modified uni-traveling-carrier photodiode (MUTC-PD) is optimized by improving the illumination uniformity. The saturation photocurrent of the device at 20 GHz increases from 15 mA to 60 mA under 5 V reverse bias, at the cost of a decrease in optical coupling efficiency by about 25%. The experimental results are in fair agreement with simulations of electric field variation inside the PD under different illumination uniformity.