Fig. 6
From: Modelling and optimization of Ge/GaAs uni-travelling carrier photodiodes

Small signal optoelectronic frequency response. Both simulations measured at a photocurrent with optical output and wavelength (λ) for input light source is 1550nm. (a) Frequency response simulation versus device size for Ge/GaAs UTC-PDs at a bias voltage of -2V. (b) Frequency response simulation for a 2 µm Ge/GaAs UTC-PD under different bias conditions.