Very low power nonlinear directional coupling in a p-i (MQW)-n vertical coupler using an electrooptic feedback

An optically controlled 1*2 optical switch based on a vertically arranged directional coupler in which the guiding regions are GaAs/GaAlAs multiple quantum wells is discussed. The device can be switched electrically in a very efficient way (5-V driving voltage for a 330- mu m-long sample) as well as optically. When connected to a constant-current source, the system shows high optical nonlinearities and can be all-optically switched with very low incident optical power on the order of 0.1 mW.<
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