Towards an Er-doped Si Nanocrystal Sensitized Waveguide Laser – the Thin Line between Gain and Loss

Important progress is being made in the development of a Si based waveguide laser operating at 1.5 μm. The gain medium responsible for the recent progress is Er-doped Si nanocrystal co-doped SiO2, a composite material that can potentially be fabricated using a VLSI compatible process. The material combines the broad absorption spectrum of Si nanocrystals with the efficient narrow linewidth emission of Er ions. This combination promises to enable the fabrication of a broadband pumped integrated optical amplifier or laser in a Si based materials system. In this paper we systematically discuss the applicability of Si nanocrystals to serve as sensitizers for Er, relating the available data to key sensitizer requirements.