Raman silicon nanocavity laser with efficient light emission from the edge of an adjacent waveguide

A Raman nanocavity laser can emit light into free space and into a properly designed waveguide adjacent to the cavity by mode coupling. In common device designs, the emission from the edge of this waveguide is relatively weak. However, a Raman silicon nanocavity laser with strong emission from the waveguide edge would be advantageous for certain applications. Here we investigate the increase in the edge emission that can be achieved by adding photonic mirrors to the waveguides adjacent to the nanocavity. We experimentally compare devices with and without photonic mirrors: the edge emission for devices with mirrors is 4.3 times stronger on average. This increase is analyzed using coupled-mode theory. The results indicate that the control of the round-trip phase shift (between the nanocavity and the mirror) and an increase of the quality factors of the nanocavity are important for further enhancement.