Thermally induced non-linearity in a CROW photonic crystal

Abstract

Photonic crystals are materials that interact with light similarly to the way electrons interact with regular ionic crystals. Their unique control over the propagation of light can be used in the fabrication of a wide range of optic devices. We study an InGaP coupled resonator optical wave guide (CROW) photonic crystal. The membrane contains three resonant cavities that exhibit non-linear behaviour, which can be attributed to both the Kerr effect and local heating of the material. The CROW is of interest as the cavities can function as an optic switch through their non-linearity. A brief overshoot of the steady state intensity is observed for off-non switches. This overshoot is used to demonstrate that the thermally induced non-linearity in the CROW is signiffcant. The thermalisation time of a cavity is estimated to be roughly 4 microseconds, based on the decay of the overshoot.