Sb-based coupled quantum wells for efficient broadband intersubband all-optical switches

We optimized a cTQW structure for both switching energy and response time using InGaAs/AlAs/AlAsSb material system. In such a structure, we expect switching energy to be in the range of a few 100s to a few 10s of fJ (few 10s of nW) depending on the growth optimization. We estimated the LO-phonon assisted relaxation time to be about 500 fsec (switching speeds exceeding 1THz) with multi-wavelength applicability. This low energy and high speed QW structure is ideal for realizing highly efficient gate switch for futuristic all-optical communication networks with bit rates exceeding few 100 Gb/s.