Multiple Quantum Well Heterostructures Showing Optical Nonlinearities at Low Intensity and Fast Recovery

Abstract

This paper focuses on photogenerated carrier nonlinearities in InGaAs/InAlAs quantum wells (QWs) that use low optical power, display a relatively fast recovery time (280 ps down to 35 ps), and excellent optical properties in terms of the sharpness of the absorption edge. A guided-wave, all-optical switching device is demonstrated as an application, at a wavelength which is of interest to telecommunication systems (1.55 μm) and requires low control energy (<0.3 pJ/pulse). A key issue here is that the controlled introduction of defects in the QW heterostructures allows the time response to be fastened significantly without being detrimental to the performance of the device in terms of on-off contrast and switching energy. The preparation procedure is compatible with metalorganic-based growth techniques widespread in optoelectronics at 1.55 μm.