Dynamic group velocity control in a mechanically tunable photonic-crystal coupled-resonator optical waveguide

We describe a tunable slow light device based on a photonic-crystal with a mechanically adjustable coupled-resonator optical waveguide structure. The lateral energy confinement is implemented along a lattice shear defect with the group velocity actively controlled by shifting the shear along the defect interface over a distance of one crystal period. The group velocity tuning range can be anywhere from arbitrarily small (determined by the waveguide structure) to near the value expected in bulk media. We present the theory and a demonstration (via simulation) of a device configuration that is realistic to fabricate and achieves a tunable range of group velocity spanning at least three orders of magnitude. The conditions for stopping the light are also discussed for different configurations.