All-optical polarisation switching at 1.5 /spl mu/m in In/sub 1-x/Ga/sub x/As/sub y/(P/sub 1-y/)-InGaAsP multiple quantum wells

Summary form only given. All-optical polarisation switches based on the excitation of spin polarised electrons in GaAs multiple quantum wells (MQWs) have been demonstrated previously with recovery times in the range 20 to 80 ps at wavelengths around 850 nm. In this work, we have studied the well width dependence of spin-dependent optical nonlinearities and spin relaxation times in InGaAsP MQWs and demonstrated all-optical polarisation switching with a recovery time as short as 5.5 ps at wavelengths compatible with all-optical soliton communication systems.