INP-INGAAS UNI-TRAVELING-CARRIER PHOTODIODE WITH IMPROVED 3-DB BANDWIDTH OF OVER 150 GHZ

Uni-traveling-carrier photodiodes (UTC-PD's) with ultrafast response a nd high-saturation output are reported. It is experimentally demonstra ted that the photoresponse of UTC-PD's is improved by incorporating a step-like potential profile in the photoabsorption layer. The fabricat ed device shows a peak electrical 3-dB bandwidth of 152 GHz at a low r everse bias voltage of -1.5 V. The output voltage can be increased to as high as 1.9 V at higher reverse bias voltages with the 3-dB bandwid th staying at over three-quarters of the maximum value. To our knowled ge, the obtained response is the fastest among those reported for 1.55 -mu m wavelength photodiodes.