Ultrafast all-optical switching using near-infrared intersubband transitions in InGaAs/AlAsSb quantum well structures

Summary form only given. The intersubband transition (ISB-T) in quantum wells is attractive due to its ultrafast relaxation, large transition dipole moment, and widely tunable transition wavelength. Various proposals and feasibility studies of ultrafast optoelectronic devices utilizing the ISB-T, such as all-optical switch or modulator, have been reported. Recently ISB-T at communication wavelengths, from 1.3 /spl mu/m to 1.55 /spl mu/m, was reported for InGaAs-AlAsSb quantum wells. However, the experimental study of intersubband relaxation dynamics, which is very important for ultrafast operation of ISB-T based optoelectronic devices has not yet been reported at the wavelength shorter than 2.5 /spl mu/m. We show in this paper the first observation of picosecond all-optical switching based on the ISB-T at the near-infrared wavelengths down to sub-2 /spl mu/m range in InGaAs-AlAsSb quantum well lattice-matched on InP substrate.