Design optimization of a modified Uni-Traveling- carrier photodiode for high optical power operation

We systematically investigated the design optimization of an InGaAs/InP modified Uni-Traveling-Carrier Photodiode (MUTC-PD) under high optical power input conditions. Based on internally fabricated experimental devices for a baseline design, we first achieved an excellent match between our experimental and simulation results under low optical power density of 1.4 mW/μm2, demonstrating the accuracy of our simulation model. Based on this model we showed that as optical power injection increases, the intrinsic bandwidth of the MUTC-PD degradation is the primary limitation on its high-speed response. We quantitatively analyzed the fundamental carrier transport physics and key design parameters affecting intrinsic bandwidth degradation under these conditions. In particular cliff layer doping concentration was found to be a very sensitive parameter affecting the MUTC-PD Optical Electrical (OE) intrinsic bandwidth. Based on detailed simulated results, we realized an optimized device design that is capable of achieving a 3 dB bandwidth of approximately 230 GHz at 10 mW/μm2 input optical power density for the first time. •We studied the performance of a 5-μm-diameter MUTC-PD and comparing with experimental results on fabricated devices.•We investigated key epitaxial structural parameters on MUTC-PD performance to alleviate the space charge effect.•An optimized MUTC-PD design was obtained that can achieve over a 230GHz 3dB bandwidth at 10mW/μm2 optical power density.•A small variation in cliff layer doping has a strong impact on MUTC-PD carrier transport under high optical power injection.