Optical gain in silicon

Luca Dal Negro, Lorenzo Pavesi, Georg Pucker +2 more

Manon A. Lourenco, R. Gwilliam, Kevin Peter Homewood

Here we report on measurements of optical gain at 1.5μm 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 5×10−19cm2, 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.

Joseph H. Simmons, Kelly S. Potter

Gerald M. Miller, Ryan M. Briggs, Harry A. Atwater

We use a rate equation approach to model the conditions for optical gain in nanocluster sensitized erbium in a slot waveguide geometry. We determine the viability of achieving net gain for the range of reported values of the carrier absorption cross section for silicon nanoclusters. After accounting for the local density of optical states modification of the emission rates, we find that gain is impossible in continuous wave pumping due to carrier absorption, regardless of the carrier absorption cross section. We, therefore, propose a pulsed electrical operation scheme which mitigates carrier absorption by taking advantage of the short lifetime of silicon nanoclusters compared to erbium. We show that pulsed excitation of a 10 nm layer achieves a modal gain of 0.9 dB/cm during each pulse. Furthermore this gain can be increased to 2 dB/cm by pumping a 50 nm layer.

Pasquale Nardone, Paul Mandel

Petr P Vasil'ev, Ian H. White