Controlling microwave signals by means of slow and fast light effects in SOA-EA structures

We present a novel scheme for the control of microwave signals in the optical domain. We propose the use of alternating amplifying and absorbing sections to implement phase control by using fast and slow light effects in semiconductors. The potential benefits from the proposed semiconductor optical amplifier and electroabsorber structures are the high tuning speed, the continuous scan of the phase delay that brings antenna angular continuing scanning, the small size, the capability of integration, the low insertion losses, and the low bias voltage. We have obtained phase changes of almost 60deg around 10 GHz using commercially available components that were not optimized for this purpose. These results indicate a potential for several microwave photonic applications including the change of the direction of the radiation pattern of photonic phase-array antennas or the implementation of fast tunable microwave photonic filters.