Semiconductor microcavity solitons

Spatial solitons in nonlinear optical resonators are structures, self localized in a balance of diffraction and nonlinear effects. Due to their bistability they can carry information and are thus interesting for schemes of parallel optical information processing. Various types of spatial cavity solitons exist: bright-, dark-, phase solitons, a special form are vortices (which are tristable) which illustrate vividly the relation of optics to fluids. For technical applications speed is important. We have therefore shown the existence and the manipulation (such as switching solitons on and off) of bright and dark solitons in semiconductor GaAs/GaAlAs quantum-well microcavities. In analogy to 1D diffraction- free discrete solitons we have numerically found that in photonic crystal microresonators the soliton size can be decreased down to /spl sim/1/spl lambda/, increasing the possible information density two orders of magnitude over normal solitons with diffraction.