Tunable higher-order sideband spectra in a waveguide-coupled photonic crystal molecule beyond the weak-excitation approximation

We investigate light transmission obtained from a hybrid optical system composed of a pair of directly coupled photonic crystal cavities called a photonic crystal molecule, a single semiconductor quantum dot, and a waveguide beyond the weak-excitation approximation. We take account of nonlinear terms in the Heisenberg-Langevin equations and give an effective method to deal with such a problem. It is shown, owing to the presence of nonlinear terms, that the efficient generation of high-order sidebands with large amplitudes can be realized with experimentally achievable system parameters. The results obtained here may be useful for gaining further insight into the properties of solid-state cavity quantum electrodynamics (CQED) system and find applications in harnessing the CQED nonlinearity to manipulate photons in a photonic crystal platform.