Ge-on-Si p-i-n Photodiodes With a 3-dB Bandwidth of 49 GHz

Fast Ge-on-Si p-i-n photodiodes are fabricated and their frequency response is measured up to 67 GHz at a wavelength of 1550 nm. At a bias voltage of -2 V, a 3-dB bandwidth (BW) of 49 GHz is achieved. This is to the best of the authors' knowledge the highest BW ever published for Ge photodiodes.