Coherent control of quantum-well excitons in a resonant semiconductor microcavity for high-speed all-optical switching

Coherent control of excitons in quantum wells embedded in a resonant planar semiconductor microcavity versus in quantum wells without the cavity at high repetition rates is investigated theoretically to determine the practical constraints for application in high bit-rate optical switching, It is shown that pi-shifted pulse pairs are optimal to coherently populate and depopulate the QW on the 100-fs timescale, For the cavity-free case, the small optical nonlinearity will require devices incorporating similar to 100 quantum wells; the resonant enhancement of the confined mode for the case of the cavity leads to an effective increase in the optical nonlinearity and thus a reduction of the required number of quantum wells to similar to 10. In addition, switch architectures that avoid interferometers, and thus will have superior temperature and mechanical stability, based on the microcavity are proposed, We believe that although room-temperature operation of a 100-Gb/s switch based on this principle may be difficult, operation at liquid-nitrogen temperature should be feasible.