9314185 LiKamWa The speed of opto-electronic devices fabricated using MQWs are governed by the rate of carrier removal from the MQW region. We have previously shown that, by applying an electric field across the MQW, carrier sweep-out significantly improves on the recovery of an all-optical directional coupler switch. In most devices, carrier sweep-out is achieved through vertical transport across the quantum wells and in these cases, the carrier escape mechanisms are a combination of thermionic emission, tunneling, scattering and recombination. Significant carrier re-trapping can also take place in adjacent wells and this slow down the recovery rate of the devices. In this novel approach, we propose to sweep the photo-generated carriers away from the switching region by lateral sweep-out in a horizontal electric field. The rate of carrier removal in this case would then be dependent on the guided spot size, the electric field and the carrier drift velocities. The device recovery rate would also be a second order exponential of the form y=e -12/A, which has a more complete recovery in the long time regime, compared to the exponential recovery normally associated with thermionic emission times. Lateral carrier sweep-out should also be applicable to a wide variety of other MQW opto-electronic devices. ***
