High-speed monolithic InP/InGaAs pin-photodiode array with small pitch

Monolithic arrays of four InP/InGaAs pin photodiodes for wavelength division multiplexing applications have been fabricated on semi-insulating InP substrate. The diodes have a diameter of 30 mu m on a 60 mu m pitch. Deep trenches are used to isolate the individual diodes from each other. A crosstalk below -30 dB is achieved for frequencies up to about 3.3 GHz. Pulse measurements at the individual diodes show a falltime of 33 ps corresponding to a 3 dB bandwidth in excess of 10 GHz.