Outcoupling of light generated in a monolithic silicon photonic crystal nanocavity through a lateral waveguide

We report the design, fabrication and optical investigation of silicon nanocavity light sources based on silicon on insulator photonic crystal nanocavities. The planar geometry of the two-dimensional photonic crystal allows light to be efficiently out-coupled into a planar photonic circuit and our results demonstrate enhanced light transmission from a defect nano-cavity into a W1 photonic crystal waveguide. When compared to the sample without the cavity, we observe an 11-fold enhancement of the luminescence emitted from the cleaved facets of the waveguide measured at the cavity wavelength. The emission exhibits a characteristically strong spatial dependence, confirming that it indeed arises from light generated in the cavity and out-coupled via the waveguide. The obtained cavity mode frequency and spatial dependence are in excellent agreement with finite-difference time-domain simulations and their dependence on the photonic crystal structural properties.