  We present an experimental and theoretical study of a system consisting of
two spatially separated self-assembled InGaAs quantum dots strongly coupled to
a single optical nanocavity mode. Due to their different size and compositional
profiles, the two quantum dots exhibit markedly different DC Stark shifts. This
allows us to tune them into mutual resonance with each other and a photonic
crystal nanocavity mode as a bias voltage is varied. Photoluminescence
measurements show a characteristic triple peak during the double anticrossing,
which is a clear signature of a coherently coupled system of three quantum
states. We fit the entire set of emission spectra of the coupled system to
theory and are able to investigate the coupling between the two quantum dots
via the cavity mode, and the coupling between the two quantum dots when they
are detuned from the cavity mode. We suggest that the resulting quantum
V-system may be advantageous since dephasing due to incoherent losses from the
cavity mode can be avoided.
