Extraordinary optical gain from silicon implanted with erbium

Here we report on measurements of optical gain at 1.5 mu m in crystalline silicon. Gain is achieved by the incorporation of the rare earth erbium in silicon. A method was developed to enable the gain measurement in short silicon waveguides. Crucially, gain values obtained are significantly greater than previously supposed. We have measured a lower limit for the optical cross section for Er3+ of 5x10(-19) cm(2), 30 times higher than previously anticipated. Given these higher values, this system now offers a realistic route to the production of electrically pumped silicon optical amplifier and laser devices using standard silicon process technology. (C) 2007 American Institute of Physics.