Ultrafast all-optical switching using intersubband transitions in InGaAs/AlAs/AlAsSb quantum wells

Abstract

Ultrafast all-optical switch based on intersubband transitions in InGaAs/AlAs/AlAsSb quantum well is described. Because of very fast intra-band relaxation in conduction band, we can obtain very fast response of around 1ps. The operation principles and characteristics as an absorption saturation type device are described. Also described is the operation as an all-optical phase modulator. With Mach-Zehnder interferometer configuration, error free all-optical demultiplexing operation from 160-Gb/s to 40-Gb/s was achieved.