50 GHz operation of waveguide integrated photodiode at 1.55 mu m

The development of high speed optical communication networks operating at bit rates above 40 Gbit/s necessitates the availability of accordingly fast photodetectors for a wavelength of 1.55 mu m. Evanescently coupled waveguide integrated photodiodes with an optimised metallisation scheme are presented. A 6 mu m wide and 20 mu m long photodiode exhibits a transit-time limited bandwidth of 44 GHz and an internal quantum efficiency of 90%.