2.5 Gbit/s polycrystalline germanium-on-silicon photodetector operating from 1.3 to 1.55 mu m

We report on a fast polycrystalline germanium-on-silicon heterojunction photodetector for the near-infrared. The device exhibits a pulse response faster than 200 ps, allowing operation at 2.5 Gbit/s as testified by open eye diagrams. This polycrystalline device, with responsivities of 16 and 5 mA/W at 1.3 and 1.55 mum, respectively, and dark currents of 1 mA/cm(2), is entirely integrable on standard silicon electronics and is an appealing low-cost candidate for fiber-to-the-home communication networks. (C) 2003 American Institute of Physics.