Group delay measurements on photonic crystal resonators

The authors have investigated the group delay of light propagating through photonic crystal resonators fabricated in GaAs membranes. The group delay was measured by detecting the phase shift of a microwave signal which was modulated onto the light. The group delay was found to increase linearly with the quality factor of the resonator. A maximum group delay of 132ps was observed for a resonator with a quality factor of 82 000.