Three Operation Modes for Tb/s All-Optical Switching With Intersubband Transitions in InGaAs/AlAs/AlAsSb Quantum Wells

We report on ultra-fast intersubband transitions in strained coupled double InGaAs/AlAs/AlAsSb quantum wells in terms of modeling, fabrication, and characterization of the structures. Our experimental results demonstrate the capability of the studied structures to perform Tb/s all-optical switching in the telecommunication wavelength range employing exclusively intersubband transitions. The coupled double quantum wells embedded into a ridge-waveguide can be explored as an inline single-wavelength all-optical switch at 1430 or 1730 nm, with response times of 400 fs and 2 ps, respectively. These structures can also be operated in a dual-wavelength mode, which allows a straightforward separation of signal pulses at 1730 nm from control pulses at 1430 nm by relaxed spectral filtering at the output of the device.