| All-optical switch is the key device to achieve the fast, transparent and none-block optical information switching of the all-optical communication network, also the basic device for optical computation and interconnection. The demand for optical switch with high performance becomes more and more urgent with the development of the optics fiber communication technologies and researchers all of the world have done many study of it in recent years. Ultrafast all-optical switch can be implemented by the characteristic of the pecosecond electron spin relaxation and strong optical nonlinearity of exciton absorption saturation of semiconductor quantum wells. It is studied in this article of the spin relaxation mechanism, exciton absorption saturation mechanism including phase space filling, Coulomb screening and collision broadening of the InGaAs/InP multiple-quantum-wells. A five level model was introduced to simulate the carrier density evolution of the pump-probe configuration and the subsequent absorptive and refractive index change and the circular polarization dichroism, the performance of the optical switch based on it was also calculated. Samples with 60 periods InGaAs quantum wells was designed and prepared using MOCVD,. Femtosecond laser pulse experiment using pump-probe configuration was carried out to implement the all-optical switch operation.The physics and numerical calculation of band-gap renormalization of the quantum wells was studied, the influence of the combined effects of PSF, CS and BGR on the dynamical shift of the exciton resonance was investigated. Some improvement scheme to eliminate the limitations of the slow carrier recombination speed on the switch was introduced, including the asymmetry Fabry-Perot cavity design, low-temperature-grown of material with Be doped and the multiple-quantum-wells with photon crystal structure optical switch based on the optical Stark effect.
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